From The Graduate School of Arts and Sciences At Harvard University: “Streamlining the Search for Black Holes”

From The Graduate School of Arts and Sciences

At

Harvard University

3.9.23
Paul Massari
Photos by David Salafia and Shanika Galaudage

Horizons scholar Floor Broekgaarden brings data science to the study of stars.

M.Weiss/NASA/CXC//Harvard-Smithsonian Center for Astrophysics

Floor Broekgaarden was rifling through her dad’s library in the basement of her childhood home in the Netherlands. A particular volume caught her eye: A Brief History of Time by the late theoretical physicist Stephen Hawking. Curious, the 14-year-old took it with her and spent months trying to understand Hawking’s ideas about space, time, and special relativity. She became particularly interested in one cosmic phenomenon: black holes.

“They seemed like these extreme and mysterious objects in our universe,” she says. “I was fascinated.”

Floor Broekgaarden is a PhD candidate in astronomy.

Broekgaarden brings that childhood fascination with the cosmos to her research as a PhD student in astronomy at Harvard’s Graduate School of Arts and Sciences. In her 2023 Harvard Horizons project Gravitational Wave Paleontology: A New Frontier to Explore the Lives of Stars to the Edge of Our Observable Universe, she merges astrophysics and big data in her quest to provide new insights into the death—and life—of stars.

Smaller and More Challenging

Daniel Holz, a professor at the University of Chicago who sits on Broekgaarden’s dissertation committee, says that the study of black holes advances understanding of fundamental physics and the origins of the cosmos. “They provide extreme tests of the Theory of General Relativity,” he says. “They also teach us about the birth and evolution of the first stars, the age and composition of the universe, and a host of other important topics in astronomy.”

Most of the black holes identified and studied by astronomers so far are supermassive. Scientists are not sure how they form. One possibility is that when one particularly massive star collapses on itself, it accretes gas and other stars or black holes to grow to a size that can reach to millions or even billions of times its original mass. Because supermassive black holes are so immense, astronomers can infer their existence from the way that a galaxy’s stars revolve around them or from light that is produced when it accretes gas.

Broekgaarden studies stellar-mass black holes, which result from the collapse of a single star. Because they are millions of times less massive than a supermassive black hole, stellar-mass black holes are far more difficult to identify. “We’ve inferred the existence of many supermassive black holes by now,” Broekgaarden says. “Stellar-mass black holes are much more challenging to observe because they’re so small.”

The size of stellar-mass black holes belies their importance as celestial phenomena, not only because they might eventually come together in supermassive black holes, but also because they are critical for a much richer understanding of the cosmos. The stars that form stellar-mass black holes play a crucial role in enriching our universe with heavy elements like sodium, but also oxygen and others that we see on Earth today.

Until now a stellar-mass black hole could be identified only when it sheered off material from a neighboring star. As the material flows toward the black hole, it emits x-ray light from which astronomers can infer the void’s existence. In terms of efficacy, though, this method is the astronomical equivalent of finding a needle in a haystack—multiplied by a power of 10.

In 2015, scientists discovered that when two stellar-mass black holes collide, they could be observed by the gravitational waves they emitted instead of light.

Gravitational waves. Credit: W.Benger-Zib. MPG Institute for Gravitational Physics (DE)

Using this approach, astronomers have identified five times as many stellar black holes in the past eight years as they had in the more than 40 years before. “We are in the midst of a golden age of black hole data,” says Holz. “Observations are improving day by day, and our catalogs of black holes continue to swell.” Instruments and methods are evolving so quickly that, within the next decade, scientists expect to detect perhaps a million stellar black holes a year.

Broekgaarden’s doctoral advisor at Harvard, Professor of Astronomy Edo Berger, says that scientists can use the black holes being found through gravitational waves to decipher how they formed and evolved from their original starting point as massive stars. “In a way, this is akin to studying the fossil record to understand the behavior of animals that are now extinct, and how they lived and evolved,” he explains. “Hence ‘gravitational wave paleontology.’”

Floor Broekgaarden presenting on stage as part of the International Gravitational Wave meeting “GWPAW” in Melbourne, Australia, December 2022. This slide presents the rapid increase in gravitational-wave detections over the coming years.

A Cosmic Game of Battleship

The discovery also raised a question—one that Broekgaarden hopes to answer in her research: How is it that two stellar black holes come together and merge? It’s not unusual to find massive stars in pairs, but usually when one becomes a supernova and explodes, the other tends to drift away from, not toward, its partner. “My question is really, ‘What makes some of these stars so special?’” the Horizons scholar says. “What processes in their lives—how they were formed and how they died—makes it so that maybe one in a million of these pairs stay together, merge as black holes, and form these gravitational waves?”

A greater understanding of how massive stars live and die requires the development of computer simulations that model the universe from the Big Bang to today—an unimaginably complex task rife with uncertainties. That’s where Broekgaarden’s work comes in. A data scientist as well as an astrophysicist, the PhD student for the first time used new statistical techniques to incorporate different classes of uncertainty and look at them simultaneously. “The theoretical framework and algorithms that Floor developed provide the translation from the observed black hole properties—measured through gravitational waves—to the original stars that formed them and the full evolutionary path of that process,” says Berger.

Broekgaarden’s algorithm also addresses the key bottlenecks in complex modeling: cost and time. Modeling billions and billions of stars from the Big Bang until today is very computationally expensive and can take years to complete. Broekgaarden developed an algorithm that works a bit like the old board game Battleship where the object is to locate your opponent’s vessel in as few guesses as possible.

“Like the game, my algorithm begins with random guesses and then, once it scores a ‘hit’ and finds a pair of black holes that collide, [it] adapts and revolves the simulation around that area to look for more,” she explains. “Using this method, we can speed up simulations by more than a factor of 100. So, instead of you know, waiting 300 days—almost a year—you now have to wait only three days. It’s a huge difference.”

Holz says that Broekgaarden’s work is at the very cutting edge of human understanding of how the universe makes its black holes. “This is one of the most exciting and important topics in astrophysics, and Floor is lighting the black hole path.”

Broekgaarden says she has high hopes for her research—and her Horizons project: to advance understanding of how elements—and the universe itself—evolved.

“Massive stars drive the processes that are the basis of the cosmos,” she says. “As we study them, I think we’ll find a lot of surprises along the way. We’ve already had a few so far!”

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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The Graduate School of Arts and Sciences (GSAS) is the largest of the twelve graduate schools of Harvard University. Formed in 1872, GSAS is responsible for most of Harvard’s graduate degree programs in the humanities, social sciences, and natural sciences. The school offers Master of Arts (AM), Master of Science (SM), and Doctor of Philosophy (PhD) degrees in approximately 58 disciplines.

Academic programs offered by the Harvard Graduate School of Arts and Sciences have consistently ranked at the top of graduate programs in the United States. The School’s graduates include a diverse set of prominent public figures and academics. The vast majority of Harvard’s Nobel Prize-winning alumni earned a degree at GSAS. In addition to scholars and scientists, GSAS graduates have become U.S. Cabinet Secretaries, Supreme Court Justices, foreign heads of state, and heads of government.

GSAS was formally created as the Graduate Department of Harvard University in 1872 and was renamed the Graduate School of Harvard University in 1890. Women were not allowed to enroll in GSAS until 1962.

The Graduate School of Arts and Sciences forms part of the Faculty of Arts and Sciences (FAS), along with Harvard College, the Harvard John A. Paulson School of Engineering and Applied Sciences, and the Harvard Division of Continuing Education. The dean of the Graduate School of Arts and Sciences, who reports to the dean of the Faculty of Arts and Sciences, is charged with the responsibility of implementing and supervising the policies of the faculty in the area of graduate education. In the administration of academic policy, the dean is guided by the Administrative Board and the Committee on Graduate Education. The dean is assisted by an administrative dean of GSAS, who has day-to-day responsibility for the operations of the school, a dean for admissions and financial aid, and a dean for student affairs. While the GSAS office oversees the processing of applications, financial aid and fellowships, thesis guidelines, and graduate student affairs, the individual departments in FAS retain considerable autonomy in the administration of their respective graduate programs.

The Faculty of Arts and Sciences oversees GSAS and is responsible for setting the conditions of admission, for providing courses of instruction for students, for directing their studies and examining them in their fields of study, for establishing and maintaining the requirements for its degrees and for making recommendations for those degrees to Harvard’s Governing Boards, for laying down regulations for the governance of the school, and for supervising all its affairs. The dean of GSAS is responsible for implementing and supervising the policies of the faculty in the area of graduate education.

In addition to its own master’s and PhD programs, GSAS nominally oversees the PhD programs in Harvard’s professional schools: Harvard Business School, Harvard Divinity School, the Harvard Graduate School of Education, Harvard Medical School, the Harvard T. H. Chan School of Public Health, the Harvard Graduate School of Design, and the John F. Kennedy School of Government.

Harvard University is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s bestknown landmark.

Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

The Massachusetts colonial legislature, the General Court, authorized Harvard University’s founding. In its early years, Harvard College primarily trained Congregational and Unitarian clergy, although it has never been formally affiliated with any denomination. Its curriculum and student body were gradually secularized during the 18th century, and by the 19th century, Harvard University (US) had emerged as the central cultural establishment among the Boston elite. Following the American Civil War, President Charles William Eliot’s long tenure (1869–1909) transformed the college and affiliated professional schools into a modern research university; Harvard became a founding member of the Association of American Universities in 1900. James B. Conant led the university through the Great Depression and World War II; he liberalized admissions after the war.

The university is composed of ten academic faculties plus the Radcliffe Institute for Advanced Study. Arts and Sciences offers study in a wide range of academic disciplines for undergraduates and for graduates, while the other faculties offer only graduate degrees, mostly professional. Harvard has three main campuses: the 209-acre (85 ha) Cambridge campus centered on Harvard Yard; an adjoining campus immediately across the Charles River in the Allston neighborhood of Boston; and the medical campus in Boston’s Longwood Medical Area. Harvard University’s endowment is valued at $41.9 billion, making it the largest of any academic institution. Endowment income helps enable the undergraduate college to admit students regardless of financial need and provide generous financial aid with no loans The Harvard Library is the world’s largest academic library system, comprising 79 individual libraries holding about 20.4 million items.

Harvard University has more alumni, faculty, and researchers who have won Nobel Prizes (161) and Fields Medals (18) than any other university in the world and more alumni who have been members of the U.S. Congress, MacArthur Fellows, Rhodes Scholars (375), and Marshall Scholars (255) than any other university in the United States. Its alumni also include eight U.S. presidents and 188 living billionaires, the most of any university. Fourteen Turing Award laureates have been Harvard affiliates. Students and alumni have also won 10 Academy Awards, 48 Pulitzer Prizes, and 108 Olympic medals (46 gold), and they have founded many notable companies.

Colonial

Harvard University was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America’s first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge (UK) who had left the school £779 and his library of some 400 volumes. The charter creating the Harvard Corporation was granted in 1650.

A 1643 publication gave the school’s purpose as “to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust.” It trained many Puritan ministers in its early years and offered a classic curriculum based on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. Harvard University has never affiliated with any particular denomination, though many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches.

Increase Mather served as president from 1681 to 1701. In 1708, John Leverett became the first president who was not also a clergyman, marking a turning of the college away from Puritanism and toward intellectual independence.

19th century

In the 19th century, Enlightenment ideas of reason and free will were widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties. When Hollis Professor of Divinity David Tappan died in 1803 and President Joseph Willard died a year later, a struggle broke out over their replacements. Henry Ware was elected to the Hollis chair in 1805, and the liberal Samuel Webber was appointed to the presidency two years later, signaling the shift from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.

Charles William Eliot, president 1869–1909, eliminated the favored position of Christianity from the curriculum while opening it to student self-direction. Though Eliot was the crucial figure in the secularization of American higher education, he was motivated not by a desire to secularize education but by Transcendentalist Unitarian convictions influenced by William Ellery Channing and Ralph Waldo Emerson.

20th century

In the 20th century, Harvard University’s reputation grew as a burgeoning endowment and prominent professors expanded the university’s scope. Rapid enrollment growth continued as new graduate schools were begun and the undergraduate college expanded. Radcliffe College, established in 1879 as the female counterpart of Harvard College, became one of the most prominent schools for women in the United States. Harvard University (US) became a founding member of the Association of American Universities in 1900.

The student body in the early decades of the century was predominantly “old-stock, high-status Protestants, especially Episcopalians, Congregationalists, and Presbyterians.” A 1923 proposal by President A. Lawrence Lowell that Jews be limited to 15% of undergraduates was rejected, but Lowell did ban blacks from freshman dormitories.

President James B. Conant reinvigorated creative scholarship to guarantee Harvard University’s preeminence among research institutions. He saw higher education as a vehicle of opportunity for the talented rather than an entitlement for the wealthy, so Conant devised programs to identify, recruit, and support talented youth. In 1943, he asked the faculty to make a definitive statement about what general education ought to be, at the secondary as well as at the college level. The resulting Report, published in 1945, was one of the most influential manifestos in 20th century American education.

Between 1945 and 1960, admissions were opened up to bring in a more diverse group of students. No longer drawing mostly from select New England prep schools, the undergraduate college became accessible to striving middle class students from public schools; many more Jews and Catholics were admitted, but few blacks, Hispanics, or Asians. Throughout the rest of the 20th century, Harvard became more diverse.

Harvard University’s graduate schools began admitting women in small numbers in the late 19th century. During World War II, students at Radcliffe College (which since 1879 had been paying Harvard University professors to repeat their lectures for women) began attending Harvard University classes alongside men. Women were first admitted to the medical school in 1945. Since 1971, Harvard University has controlled essentially all aspects of undergraduate admission, instruction, and housing for Radcliffe women. In 1999, Radcliffe was formally merged into Harvard University.

21st century

Drew Gilpin Faust, previously the dean of the Radcliffe Institute for Advanced Study, became Harvard University’s first woman president on July 1, 2007. She was succeeded by Lawrence Bacow on July 1, 2018.

From The Niels Bohr Institute [Niels Bohr Institutet] (DK): “Intergalactic gas brings supermassive black holes at the heart of galaxies to life”

From The Niels Bohr Institute [Niels Bohr Institutet] (DK)

at

University of Copenhagen [Københavns Universitet] [UCPH] (DK)

3.9.23
Sandra I. Raimundo
Assistent Professor at DARK Cosmology Centre
Niels Bohr Institute
University of Copenhagen,
sandra.raimundo@nbi.ku.dk
+45 35 33 16 59

Marianne Vestergaard
Professor at DARK Cosmology Centre
Niels Bohr Institute
University of Copenhagen
mvester@nbi.ku.dk
+45 35 32 59 09

Kristian Bjørn-Hansen
Journalist and press contact
The Faculty of Natural and Life Sciences
University of Copenhagen
kbh@science.ku.dk
+45 93 51 60 02

Black holes-Black holes become active and grow by consuming gas captured from other galaxies. This is the finding of a new study from University of Copenhagen researchers, and shows a clear connection between the evolution of supermassive black holes and galactic interaction.

The colliding spiral galaxies NGC 2207 and IC 2163. Image: NASA and The Hubble Heritage Team.

In the outer regions of the Milky Way, our blue planet rotates in its orbit around the Sun, the massive center of our Solar System. 26,000 light-years away, a supermassive black hole known as Sagittarius A* is at the center of our galaxy. It is a sleeping giant with a mass 4.3 million times greater than our sun.

Black holes are immense forces in the Universe. They can grow into supermassive giants — and can even be many thousands of times more massive than Sagittarius A* — by consuming large amounts of mass. But the mechanisms by which they grow have been a mystery to researchers.

SGR A*, the supermassive black hole at the center of the Milky Way. Credit: NASA’s Chandra X-Ray Observatory.

Sgr A* from The European Southern Observatory [La Observatorio Europeo Austral][Observatoire européen austral][Europäische Südsternwarte](EU)(CL) Very Large Telescope (CL)(EU).

This is the first image of Sagittarius A* – [SGR A*] the supermassive black hole at the center of the Milky Way. Credit: The Event Horizon Telescope Collaboration.

Researchers from DARK at the Niels Bohr Institute, along with a colleague in the US, have now succeeded in demonstrating one effective way that activates black holes and feeds their insatiable appetites: This happens as they devour intergalactic gas transported from one galaxy to another ­– in connection with a galactic collision or as one galaxy passes close to another.

“Our observational data demonstrates that gas from galactic interactions can be transported through a galaxy and down to the black hole at the center of it. This will cause it to be activated. We see a direct connection between gas outside galaxies and the chance of active supermassive black holes,” explains Sandra Raimundo, from DARK at the Niels Bohr Institute, who is the leading scientist of the study.

Understanding how gas reaches black holes has long been an unanswered question. The researchers in this study [Nature Astronomy (below)] demonstrated one of these mechanisms.

The result is based on observations of 3,000 selected galaxies and marks the first time that researchers have obtained observational data as evidence for this mechanism that explains how black holes grow large.

“For a supermassive black hole to grow, gas must fall into it, which increases its mass. This is known as “accretion”. When this happens, we consider a black hole to be active. We can observe this because as the gas heats up, it releases huge amounts of energy in the form of electromagnetic radiation, before plummeting into the black hole. This is something that we can measure from Earth,” explains Sandra Raimundo.

Gas out of step with galaxy

The new results are interesting to the researchers because they show that a larger proportion of galaxies have active black holes when gas is moving in the opposite direction of a galaxy’s rotation, known as ‘misaligned gas’.

“These observations provide us with a clear link between interacting galaxies, ‘misaligned gas’ and active black holes, where gases are able to reach the centre of the galaxy and cause black holes to grow,” says Sandra Raimundo.

The study data also showed examples of active black holes where no misaligned gas was present in the galaxy, but where the supermassive black hole was still active. Therefore, the mechanism is not the only explanation for how supermassive black holes grow, but the data shows that it does play a significant role.

How the mechanism works is something that the researchers look forward to investigating in further research. For now, they only have theories and simulation data to explain what is happening. One thing that may play a role is that misaligned gas is unstable and out of orbit.

“Although misaligned gas comes with its own energy from rotation, its collision with opposing motions in the galaxy can cause the gas to lose that energy. In this way, the gas will be left to the gravity of the galactic core and could accelerate its fall towards the black hole at the center,” explains Sandra Raimundo, lead author of the study.

Among other things, the research may help uncover yet another mystery, as supermassive black holes at the center of galaxies are thought to play a crucial role in regulating whether a galaxy generates new stars when they are active.

“In order to study how black holes and star formation in galaxies are connected, we first need to understand how black holes develop, when and how they become active. This study gets us a lot closer to such an understanding,” comments Marianne Vestergaard, one of the co-authors on the study, and she highlights:

“The exciting thing about these observations is that it is the first time it is possible to identify gas that has been captured from other galaxies and trace it all the way down to the center, where the black hole consumes it.”

When galaxies come into close contact, gas can travel between them and feed the galaxies’ central black holes. Here’s a galactic interaction, arp273, nicknamed the “Rose Galaxies” Image: NASA, ESA, and The Hubble Heritage Team.

It may happen here in a distant future

The supermassive black hole at the center of our own Milky Way is almost completely dormant and ingests very little gas. It is however possible that the misaligned gas mechanism will one day carry gas through our Milky Way and awaken the now calm Sagittarius A* at its center.

One way this could happen is from interaction with our neighboring galaxy, Andromeda which is heading our way and could collide with the Milky Way or pass close by in some 4.5 billion years.

Andromeda Galaxy (Messier 31). Credit: Adam Evans, University of Virginia.

Milky Way merger with Andromeda. Credit: NAOJ.

Milkdromeda with Andromeda on the left-Earth’s night sky in 3.75 billion years. No one will be here on Earth to see it. Maybe humans will have escaped the Sun’s becoming a Red Giant and observe it from a new home. Credit: The National Aeronautics and Space Agency.

It is possible that gas from Andromeda could then find its way into the black hole at the center of the Milky Way.

For now perhaps we should be grateful for the low activity at the center of our galaxy, as high activity black holes can emit powerful radiation and high energy particles that, if they could reach us, could be harmful to life on our fragile blue planet.

Nature Astronomy

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.

The Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

During the 1920s, and 1930s, the Institute was the centre of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK).

Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University , The Australian National University (AU), and University of California-Berkeley , amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

From “Quanta Magazine” : “Researchers Argue Black Holes Will Eventually Destroy All Quantum States”

From “Quanta Magazine”

3.7.23
Thomas Lewton

New calculations suggest that the event horizons around black holes will ‘decohere’ quantum possibilities — even those that are far away.

Black holes effectively observe elementary particles, an effect that echoes John Wheeler’s ideas about the “participatory universe.” Kristina Armitage/Quanta Magazine

At Princeton University in the early 1970s, the celebrated theoretical physicist John Wheeler could be spotted in seminars or impromptu hallway discussions drawing a big “U.”

John Wheeler’s “participatory universe” suggests that observers make the universe real. Samuel Velasco/Quanta Magazine; adapted from John Wheeler.

The letter’s left tip represented the beginning of the universe, where everything was uncertain and all quantum possibilities were happening at the same time. The letter’s right tip, sometimes adorned with an eye, depicted an observer looking back in time, thus bringing the left side of the U into existence.

In this “participatory universe,” as Wheeler called it, the cosmos expanded and cooled around the U, forming structures and eventually creating observers, like humans and measuring apparatus. By looking back to the early universe, these observers somehow made it real.

“He would say things like ‘No phenomenon is a true phenomenon until it’s an observed phenomenon,’” said Robert M. Wald, a theoretical physicist at the University of Chicago who was Wheeler’s doctoral student at the time.

Now, by studying how quantum theory behaves on the horizon of a black hole, Wald and his collaborators have calculated a new effect that is suggestive of Wheeler’s participatory universe. The mere presence of a black hole, they’ve found, is enough to turn a particle’s hazy “superposition” — the state of being in multiple potential states — into a well-defined reality. “It evokes the idea that these black hole horizons are watching,” said co-author Gautam Satishchandran, a theoretical physicist at Princeton.

“What we have found might be a quantum mechanical realization of [the participatory universe], but where space-time itself plays the role of the observer,” said Daine Danielson, the third author, also at Chicago.

Theorists are now debating what to read into these watchful black holes. “This seems to be telling us something deep about the way gravity influences measurement in quantum mechanics,” said Sam Gralla, a theoretical astrophysicist at the University of Arizona. But whether this will prove useful for researchers inching toward a complete theory of quantum gravity is still anyone’s guess.

The effect is one of many uncovered in the past decade by physicists studying what happens when quantum theory is combined with gravity at low energies. For example, theorists have had great success thinking about Hawking radiation, which causes black holes to slowly evaporate. “Subtle effects that we hadn’t really noticed before give us constraints from which we can glean clues about how to go up toward quantum gravity,” said Alex Lupsasca, a theoretical physicist at Vanderbilt University who was not involved in the new research.

These observant black holes seem to produce an effect that’s “very arresting,” Lupsasca said, “because it feels like somehow it’s deep.”

Black Holes and Superpositions

To understand how a black hole could observe the universe, start small. Consider the classic double-slit experiment, in which quantum particles are fired toward two slits in a barrier. Those that pass through are then detected by a screen on the other side.

At first, each traveling particle seems to appear at random on the screen. But as more particles pass through the slits, a pattern of light and dark stripes emerges. This pattern suggests that each particle behaves like waves that pass through both slits at once. The bands result from the peaks and troughs of the waves either adding together or canceling one another out — a phenomenon called interference.

Now add a detector to measure which of the two slits the particle passes through. The pattern of light and dark stripes will disappear. The act of observation changes the state of the particle — its wavelike nature disappears entirely. Physicists say that the information gained by the detection apparatus “decoheres” the quantum possibilities into a definite reality.

Importantly, your detector doesn’t have to be close to the slits to figure out which path the particle took. A charged particle, for example, emits a long-range electric field that might have slightly different strengths depending on whether it went through the right-hand or left-hand slit. Measuring this field from far away will still allow you to gather information about which path the particle took and will thus cause decoherence.

From left: Robert Wald, Gautam Satishchandran and Daine Danielson.
Daine Danielson (left); Sheri Lynn / Sara Kauss Photography (center); courtesy of Daine Daneilson (right)

In 2021, Wald, Satishchandran and Danielson were exploring a paradox brought about when hypothetical observers gather information in this way. They imagined an experimenter called Alice who creates a particle in a superposition. At a later time, she looks for an interference pattern. The particle will only exhibit interference if it hasn’t become too entangled with any outside system while Alice observes it.

Then along comes Bob, who is attempting to measure the particle’s position from far away by measuring the particle’s long-range fields. According to the rules of causality, Bob shouldn’t be able to influence the outcome of Alice’s experiment, since the experiment should be over by the time the signals from Bob get to Alice. However, by the rules of quantum mechanics, if Bob does successfully measure the particle, it will become entangled with him, and Alice won’t see an interference pattern.

The trio rigorously calculated that the amount of decoherence due to Bob’s actions is always less than the decoherence that Alice would naturally cause by the radiation she emits (which also becomes entangled with the particle). So Bob could never decohere Alice’s experiment because she would already have decohered it herself. Although an earlier version of this paradox was resolved in 2018 [Physical Review D] with a back-of-the-envelope calculation by Wald and a different team of researchers, Danielson took it one step further.

He posed a thought experiment to his collaborators: “Why can’t I put [Bob’s] detector behind a black hole?” In such a setup, a particle in a superposition outside the event horizon will emanate fields that cross over the horizon and get detected by Bob on the other side, within the black hole. The detector gains information about the particle, but as the event horizon is a “one-way ticket,” no information can cross back over, Danielson said. “Bob cannot influence Alice from inside of the black hole, so the same decoherence must occur without Bob,” the team wrote in an email to Quanta. The black hole itself must decohere the superposition.

“In the more poetic language of the participatory universe, it is as if the horizon watches superpositions,” Danielson said.

Using this insight, they set about working on an exact calculation of how quantum superpositions are affected by the black hole’s space-time. In a paper published in January, they landed on a simple formula that describes the rate at which radiation crosses over the event horizon and so causes decoherence to occur. “That there was an effect at all was, to me, very surprising,” Wald said.

Hair on the Horizon

The idea that event horizons gather information and cause decoherence isn’t new. In 2016, Stephen Hawking, Malcolm Perry and Andrew Strominger described how particles crossing over the event horizon could be accompanied by very low-energy radiation that records information about these particles. This insight was suggested as a solution to the black hole information paradox, a profound consequence of Hawking’s earlier discovery that black holes emit radiation.

The problem was that Hawking radiation drains energy from black holes, causing them to completely evaporate over time. This process would appear to destroy any information that has fallen into the black hole. But in doing so, it would contradict a fundamental feature of quantum mechanics: that information in the universe can’t be created or destroyed.

The low-energy radiation proposed by the trio would get around this by allowing some information to be distributed in a halo around the black hole and escape. The researchers called the information-rich halo “soft hair.”

Wald, Satishchandran and Danielson were not investigating the black hole information paradox. But their work makes use of soft hair. Specifically, they showed that soft hair is created not only when particles fall across a horizon, but when particles outside a black hole merely move to a different location. Any quantum superposition outside will become entangled with soft hair on the horizon, giving rise to the decoherence effect they identified. In this way the superposition is recorded as a kind of “memory” on the horizon.

The calculation is a “concrete realization of soft hair,” said Daniel Carney, a theoretical physicist at The DOE’s Lawrence Berkeley National Laboratory. “It’s a cool paper. It could be a very useful construction for trying to make that idea work in detail.”

But to Carney and several other theorists working at the forefront of quantum gravity research, this decoherence effect isn’t all that surprising. The long-range nature of the electromagnetic force and gravity means that “it’s hard to keep anything isolated from the rest of the universe,” said Daniel Harlow, a theoretical physicist at the Massachusetts Institute of Technology.

Total Decoherence

The authors argue that there is something uniquely “insidious” about this kind of decoherence. Usually, physicists can control decoherence by shielding their experiment from the outside environment. A vacuum, for example, removes the influence of nearby gas molecules. But nothing can shield gravity, so there’s no way to insulate an experiment from gravity’s long-range influence. “Eventually, every superposition will be completely decohered,” Satishchandran said. “There’s no way of getting around it.”

The authors therefore regard black hole horizons as taking a more active role in decoherence than was previously known. “The geometry of the universe itself, as opposed to the matter within it, is responsible for the decoherence,” they wrote in an email to Quanta.

Carney disputes this interpretation, saying that the new decoherence effect can also be understood as a consequence of electromagnetic or gravitational fields, in combination with rules set by causality. And unlike Hawking radiation, where the black hole horizon changes over time, in this case the horizon “has no dynamics whatsoever,” Carney said. “The horizon doesn’t do anything, per se; I would not use that language.”

To not violate causality, superpositions outside the black hole must be decohered at the maximum possible rate that a hypothetical observer inside the black hole could be collecting information about them. “It seems to be pointing toward some new principle about gravity, measurement and quantum mechanics,” Gralla said. “You don’t expect that to happen more than 100 years after gravity and quantum mechanics were formulated.”

Merrill Sherman/Quanta Magazine

Intriguingly, this kind of decoherence will occur anywhere there is a horizon that only allows information to travel in one direction, creating the potential for causality paradoxes. The edge of the known universe, called the cosmological horizon, is another example. Or consider the “Rindler horizon,” which forms behind an observer who continuously accelerates and approaches the speed of light, so that light rays can no longer catch up with them. All of these “Killing horizons” (named after the late 19th- early 20th-century German mathematician Wilhelm Killing) cause quantum superpositions to decohere. “These horizons are really watching you in exactly the same way,” Satishchandran said.

Exactly what it means for the edge of the known universe to watch everything inside the universe isn’t entirely clear. “We don’t understand the cosmological horizon,” Lupsasca said. “It’s super fascinating, but way harder than black holes.”

In any case, by posing thought experiments like this, where gravity and quantum theory collide, physicists hope to learn about the behavior of a unified theory. “This is likely giving us some more clues about quantum gravity,” Wald said. For example, the new effect may help theorists understand how entanglement is related to space-time.

“These effects have to be part of the final story of quantum gravity,” Lupsasca said. “Now, are they going to be a crucial clue along the way to gleaning insight into that theory? It’s worth investigating.”

The Participatory Universe

As scientists continue to learn about decoherence in all its forms, Wheeler’s concept of the participatory universe is becoming clearer, Danielson said. All particles in the universe, it seems, are in a subtle superposition until they are observed. Definiteness emerges through interactions. “That’s kind of what, I think, Wheeler had in mind,” Danielson said.

And the finding that black holes and other Killing horizons observe everything, all the time, “whether you like it or not,” is “more evocative” of the participatory universe than the other types of decoherence are, the authors said.

Not everyone is ready to buy Wheeler’s philosophy on a grand scale. “The idea that the universe observes itself? That sounds a little Jedi for me,” said Lupsasca, who nevertheless agrees that “everything is observing itself all the time through interactions.”

“Poetically, you could think of it that way,” Carney said. “Personally, I’d just say that the presence of the horizon means that the fields living around it are going to get stuck on the horizon in a really interesting way.”

When Wheeler first drew the “big U” when Wald was a student in the 1970s, Wald didn’t think much of it. “Wheeler’s idea struck me as not that solidly grounded,” he said.

And now? “A lot of the stuff he did was enthusiasm and some vague ideas which later turned out to be really on the mark,” Wald said, noting that Wheeler anticipated Hawking radiation long before the effect was calculated.

“He saw himself as holding out a lamp light to illuminate possible paths for other people to follow.”

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Please help promote STEM in your local schools.

Stem Education Coalition

Formerly known as Simons Science News, Quanta Magazine is an editorially independent online publication launched by the Simons Foundation to enhance public understanding of science. Why Quanta? Albert Einstein called photons “quanta of light.” Our goal is to “illuminate science.” At Quanta Magazine, scientific accuracy is every bit as important as telling a good story. All of our articles are meticulously researched, reported, edited, copy-edited and fact-checked.

From The Harvard-Smithsonian Center for Astrophysics Via “The Gazette” At Harvard University: “Nothing that is not there and the nothing that is”

From The Harvard-Smithsonian Center for Astrophysics

Via

“The Gazette”

At

Harvard University

2.24.23
Liz Mineo, Harvard Staff Writer

Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via The Event Horizon Telescope Collaboration released on 10 April 2019 via National Science Foundation.

This is the first image of Sagittarius A* – [SGR A*] the supermassive black hole at the center of the Milky Way. Credit: The Event Horizon Telescope Collaboration.

Wondering is a series of random questions answered by experts. For this entry, we asked the astrophysicist Avi Loeb, founding director of Harvard’s Black Hole Initiative, to help us picture the scariest void in the universe.

A black hole is a region in space where gravity is so strong that not even light can escape. It is an extreme structure of space and time. One way black holes are formed is when a star consumes its nuclear fuel and collapses because there is no energy supply to support it against gravity. When that happens, once the matter crosses the horizon of the black hole, it cannot emit any light. In the only two images captured of a black hole [above], there is a ring of light around the black hole because when it is being formed, the matter is moving extremely fast, close to the speed of light, and there is a huge release of energy and radiation. We call them black holes because once the matter falls into a black hole and there is no more radiation, it becomes completely dark and invisible to us.

Avi Loeb. “I once gave a presentation about black holes to fourth-graders at my daughter’s school. A boy asked me what would happen to his body if he got inside a black hole. As I started to explain, the teacher stopped me, saying that the kids would have nightmares.” Jon Chase/Harvard Staff Photographer.

Is a black hole really a hole? We don’t know the answer. What we know is that near the center of the black hole there is a point called singularity, where the density of the matter becomes infinite, and gravity is very strong. Albert Einstein’s Theory of General Relativity is unable to predict what happens there. In principle, you can imagine an astronaut going into a black hole. As he moved closer to the singularity, his body would be ripped apart by gravity. “I once gave a presentation about black holes to fourth-graders at my daughter’s school. A boy asked me what would happen to his body if he got inside a black hole. As I started to explain, the teacher stopped me, saying that the kids would have nightmares.” Avi Loeb.

One of the most common misconceptions about black holes is that they are a portal to some other universe. We don’t know whether there is another universe. We don’t have any evidence for that. All we see is our own universe, and although we know the universe is expanding, we don’t know if there is another place that we can go to. If I had to guess, I would say that if you fall into a black hole, you end up inside a black hole. Since we don’t have a quantum theory of gravity, we can’t really calculate what exactly happens there.

The study of black holes is important for two reasons. One is environmental, which is what an astrophysicist cares about: Black holes have a huge impact on their environment because they’re very efficient at making energy out of matter, and the energy they release can affect the evolution of galaxies significantly. The second aspect is more fundamental. We don’t know what happens at the center of a black hole because Einstein’s theory is incomplete. Any theory that we develop to unify quantum mechanics, which describes the behavior of matter on a small scale, and gravity will unveil the secrets of the universe. If we understand what happens near the center of a black hole, we will also be able to figure out what happened before the Big Bang.

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.

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Please help promote STEM in your local schools.

Stem Education Coalition

Harvard University is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best-known landmark.

Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

The Massachusetts colonial legislature, the General Court, authorized Harvard University’s founding. In its early years, Harvard College primarily trained Congregational and Unitarian clergy, although it has never been formally affiliated with any denomination. Its curriculum and student body were gradually secularized during the 18th century, and by the 19th century, Harvard University (US) had emerged as the central cultural establishment among the Boston elite. Following the American Civil War, President Charles William Eliot’s long tenure (1869–1909) transformed the college and affiliated professional schools into a modern research university; Harvard became a founding member of the Association of American Universities in 1900. James B. Conant led the university through the Great Depression and World War II; he liberalized admissions after the war.

The university is composed of ten academic faculties plus the Radcliffe Institute for Advanced Study. Arts and Sciences offers study in a wide range of academic disciplines for undergraduates and for graduates, while the other faculties offer only graduate degrees, mostly professional. Harvard has three main campuses: the 209-acre (85 ha) Cambridge campus centered on Harvard Yard; an adjoining campus immediately across the Charles River in the Allston neighborhood of Boston; and the medical campus in Boston’s Longwood Medical Area. Harvard University’s endowment is valued at $41.9 billion, making it the largest of any academic institution. Endowment income helps enable the undergraduate college to admit students regardless of financial need and provide generous financial aid with no loans The Harvard Library is the world’s largest academic library system, comprising 79 individual libraries holding about 20.4 million items.

Harvard University has more alumni, faculty, and researchers who have won Nobel Prizes (161) and Fields Medals (18) than any other university in the world and more alumni who have been members of the U.S. Congress, MacArthur Fellows, Rhodes Scholars (375), and Marshall Scholars (255) than any other university in the United States. Its alumni also include eight U.S. presidents and 188 living billionaires, the most of any university. Fourteen Turing Award laureates have been Harvard affiliates. Students and alumni have also won 10 Academy Awards, 48 Pulitzer Prizes, and 108 Olympic medals (46 gold), and they have founded many notable companies.

Colonial

Harvard University was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America’s first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge(UK) who had left the school £779 and his library of some 400 volumes. The charter creating the Harvard Corporation was granted in 1650.

A 1643 publication gave the school’s purpose as “to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust.” It trained many Puritan ministers in its early years and offered a classic curriculum based on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. Harvard University has never affiliated with any particular denomination, though many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches.

Increase Mather served as president from 1681 to 1701. In 1708, John Leverett became the first president who was not also a clergyman, marking a turning of the college away from Puritanism and toward intellectual independence.

19th century

In the 19th century, Enlightenment ideas of reason and free will were widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties. When Hollis Professor of Divinity David Tappan died in 1803 and President Joseph Willard died a year later, a struggle broke out over their replacements. Henry Ware was elected to the Hollis chair in 1805, and the liberal Samuel Webber was appointed to the presidency two years later, signaling the shift from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.

Charles William Eliot, president 1869–1909, eliminated the favored position of Christianity from the curriculum while opening it to student self-direction. Though Eliot was the crucial figure in the secularization of American higher education, he was motivated not by a desire to secularize education but by Transcendentalist Unitarian convictions influenced by William Ellery Channing and Ralph Waldo Emerson.

20th century

In the 20th century, Harvard University’s reputation grew as a burgeoning endowment and prominent professors expanded the university’s scope. Rapid enrollment growth continued as new graduate schools were begun and the undergraduate college expanded. Radcliffe College, established in 1879 as the female counterpart of Harvard College, became one of the most prominent schools for women in the United States. Harvard University became a founding member of the Association of American Universities in 1900.

The student body in the early decades of the century was predominantly “old-stock, high-status Protestants, especially Episcopalians, Congregationalists, and Presbyterians.” A 1923 proposal by President A. Lawrence Lowell that Jews be limited to 15% of undergraduates was rejected, but Lowell did ban blacks from freshman dormitories.

President James B. Conant reinvigorated creative scholarship to guarantee Harvard University’s preeminence among research institutions. He saw higher education as a vehicle of opportunity for the talented rather than an entitlement for the wealthy, so Conant devised programs to identify, recruit, and support talented youth. In 1943, he asked the faculty to make a definitive statement about what general education ought to be, at the secondary as well as at the college level. The resulting Report, published in 1945, was one of the most influential manifestos in 20th century American education.

Between 1945 and 1960, admissions were opened up to bring in a more diverse group of students. No longer drawing mostly from select New England prep schools, the undergraduate college became accessible to striving middle class students from public schools; many more Jews and Catholics were admitted, but few blacks, Hispanics, or Asians. Throughout the rest of the 20th century, Harvard became more diverse.

Harvard University’s graduate schools began admitting women in small numbers in the late 19th century. During World War II, students at Radcliffe College (which since 1879 had been paying Harvard University professors to repeat their lectures for women) began attending Harvard University classes alongside men. Women were first admitted to the medical school in 1945. Since 1971, Harvard University has controlled essentially all aspects of undergraduate admission, instruction, and housing for Radcliffe women. In 1999, Radcliffe was formally merged into Harvard University.

21st century

Drew Gilpin Faust, previously the dean of the Radcliffe Institute for Advanced Study, became Harvard University’s first woman president on July 1, 2007. She was succeeded by Lawrence Bacow on July 1, 2018.

The Harvard-Smithsonian Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory, founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

Founded in 1973 and headquartered in Cambridge, Massachusetts, the CfA leads a broad program of research in astronomy, astrophysics, Earth and space sciences, as well as science education. The CfA either leads or participates in the development and operations of more than fifteen ground- and space-based astronomical research observatories across the electromagnetic spectrum, including the forthcoming Giant Magellan Telescope(CL) and the Chandra X-ray Observatory, one of NASA’s Great Observatories.

Giant Magellan Telescope(CL) 21 meters, to be at the Carnegie Institution for Science’s NSF NOIRLab NOAO Las Campanas Observatory(CL) some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.

National Aeronautics and Space Administration Chandra X-ray telescope.

Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in the world. Its projects have included Nobel Prize-winning advances in cosmology and high energy astrophysics, the discovery of many exoplanets, and the first image of a black hole. The CfA also serves a major role in the global astrophysics research community: the CfA’s Astrophysics Data System, for example, has been universally adopted as the world’s online database of astronomy and physics papers. Known for most of its history as the “Harvard-Smithsonian Center for Astrophysics”, the CfA rebranded in 2018 to its current name in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. The CfA’s current Director (since 2004) is Charles R. Alcock, who succeeds Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982).

The Center for Astrophysics | Harvard & Smithsonian is not formally an independent legal organization, but rather an institutional entity operated under a Memorandum of Understanding between Harvard University and the Smithsonian Institution. This collaboration was formalized on July 1, 1973, with the goal of coordinating the related research activities of the Harvard College Observatory (HCO) and the Smithsonian Astrophysical Observatory (SAO) under the leadership of a single Director, and housed within the same complex of buildings on the Harvard campus in Cambridge, Massachusetts. The CfA’s history is therefore also that of the two fully independent organizations that comprise it. With a combined lifetime of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA’s founding.

History of the Smithsonian Astrophysical Observatory (SAO)

Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1,1890. The Astrophysical Observatory’s initial, primary purpose was to “record the amount and character of the Sun’s heat”. Charles Greeley Abbot was named SAO’s first director, and the observatory operated solar telescopes to take daily measurements of the Sun’s intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the Solar constant, as well as to serendipitously discover Solar variability. It is likely that SAO’s early history as a solar observatory was part of the inspiration behind the Smithsonian’s “sunburst” logo, designed in 1965 by Crimilda Pontes.

In 1955, the scientific headquarters of SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). Fred Lawrence Whipple, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO’s move to Harvard’s campus also resulted in a rapid expansion of its research program. Following the launch of Sputnik (the world’s first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the United States Air Force on Project Space Track.

With the creation of National Aeronautics and Space Administration the following year and throughout the space race, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

History of Harvard College Observatory (HCO)

Partly in response to renewed public interest in astronomy following the 1835 return of Halley’s Comet, the Harvard College Observatory was founded in 1839, when the Harvard Corporation appointed William Cranch Bond as an “Astronomical Observer to the University”. For its first four years of operation, the observatory was situated at the Dana-Palmer House (where Bond also resided) near Harvard Yard, and consisted of little more than three small telescopes and an astronomical clock. In his 1840 book recounting the history of the college, then Harvard President Josiah Quincy III noted that “…there is wanted a reflecting telescope equatorially mounted…”. This telescope, the 15-inch “Great Refractor”, opened seven years later (in 1847) at the top of Observatory Hill in Cambridge (where it still exists today, housed in the oldest of the CfA’s complex of buildings). The telescope was the largest in the United States from 1847 until 1867. William Bond and pioneer photographer John Adams Whipple used the Great Refractor to produce the first clear Daguerrotypes of the Moon (winning them an award at the 1851 Great Exhibition in London). Bond and his son, George Phillips Bond (the second Director of HCO), used it to discover Saturn’s 8th moon, Hyperion (which was also independently discovered by William Lassell).

Under the directorship of Edward Charles Pickering from 1877 to 1919, the observatory became the world’s major producer of stellar spectra and magnitudes, established an observing station in Peru, and applied mass-production methods to the analysis of data. It was during this time that HCO became host to a series of major discoveries in astronomical history, powered by the Observatory’s so-called “Computers” (women hired by Pickering as skilled workers to process astronomical data). These “Computers” included Williamina Fleming; Annie Jump Cannon; Henrietta Swan Leavitt; Florence Cushman; and Antonia Maury, all widely recognized today as major figures in scientific history. Henrietta Swan Leavitt, for example, discovered the so-called period-luminosity relation for Classical Cepheid variable stars, establishing the first major “standard candle” with which to measure the distance to galaxies. Now called “Leavitt’s Law”, the discovery is regarded as one of the most foundational and important in the history of astronomy; astronomers like Edwin Hubble, for example, would later use Leavitt’s Law to establish that the Universe is expanding, the primary piece of evidence for the Big Bang model.

Upon Pickering’s retirement in 1921, the Directorship of HCO fell to Harlow Shapley (a major participant in the so-called “Great Debate” of 1920). This era of the observatory was made famous by the work of Cecelia Payne-Gaposchkin, who became the first woman to earn a Ph.D. in astronomy from Radcliffe College (a short walk from the Observatory). Payne-Gapochkin’s 1925 thesis proposed that stars were composed primarily of hydrogen and helium, an idea thought ridiculous at the time. Between Shapley’s tenure and the formation of the CfA, the observatory was directed by Donald H. Menzel and then Leo Goldberg, both of whom maintained widely recognized programs in solar and stellar astrophysics. Menzel played a major role in encouraging the Smithsonian Astrophysical Observatory to move to Cambridge and collaborate more closely with HCO.

Joint history as the Center for Astrophysics (CfA)

The collaborative foundation for what would ultimately give rise to the Center for Astrophysics began with SAO’s move to Cambridge in 1955. Fred Whipple, who was already chair of the Harvard Astronomy Department (housed within HCO since 1931), was named SAO’s new director at the start of this new era; an early test of the model for a unified Directorship across HCO and SAO. The following 18 years would see the two independent entities merge ever closer together, operating effectively (but informally) as one large research center.

This joint relationship was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field, then affiliated with University of California- Berkeley, was appointed as its first Director. That same year, a new astronomical journal, the CfA Preprint Series was created, and a CfA/SAO instrument flying aboard Skylab discovered coronal holes on the Sun. The founding of the CfA also coincided with the birth of X-ray astronomy as a new, major field that was largely dominated by CfA scientists in its early years. Riccardo Giacconi, regarded as the “father of X-ray astronomy”, founded the High Energy Astrophysics Division within the new CfA by moving most of his research group (then at American Sciences and Engineering) to SAO in 1973. That group would later go on to launch the Einstein Observatory (the first imaging X-ray telescope) in 1976, and ultimately lead the proposals and development of what would become the Chandra X-ray Observatory. Chandra, the second of NASA’s Great Observatories and still the most powerful X-ray telescope in history, continues operations today as part of the CfA’s Chandra X-ray Center. Giacconi would later win the 2002 Nobel Prize in Physics for his foundational work in X-ray astronomy.

Shortly after the launch of the Einstein Observatory, the CfA’s Steven Weinberg won the 1979 Nobel Prize in Physics for his work on electroweak unification. The following decade saw the start of the landmark CfA Redshift Survey (the first attempt to map the large scale structure of the Universe), as well as the release of the Field Report, a highly influential Astronomy & Astrophysics Decadal Survey chaired by the outgoing CfA Director George Field. He would be replaced in 1982 by Irwin Shapiro, who during his tenure as Director (1982 to 2004) oversaw the expansion of the CfA’s observing facilities around the world.

Harvard Smithsonian Center for Astrophysics Fred Lawrence Whipple Observatory located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganization] (EU)/National Aeronautics and Space Administration SOHO satellite. Launched in 1995.

National Aeronautics Space Agency NASA Kepler Space Telescope

CfA-led discoveries throughout this period include canonical work on Supernova 1987A, the “CfA2 Great Wall” (then the largest known coherent structure in the Universe), the best-yet evidence for supermassive black holes, and the first convincing evidence for an extrasolar planet.

The 1990s also saw the CfA unwittingly play a major role in the history of computer science and the internet: in 1990, SAO developed SAOImage, one of the world’s first X11-based applications made publicly available (its successor, DS9, remains the most widely used astronomical FITS image viewer worldwide). During this time, scientists at the CfA also began work on what would become the Astrophysics Data System (ADS), one of the world’s first online databases of research papers. By 1993, the ADS was running the first routine transatlantic queries between databases, a foundational aspect of the internet today.

The CfA Today

Research at the CfA

Charles Alcock, known for a number of major works related to massive compact halo objects, was named the third director of the CfA in 2004. Today Alcock overseas one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $100M. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 Ph.D. students, more than 100 postdoctoral researchers, and roughly 25 undergraduate majors in astronomy and astrophysics from Harvard College. SAO, meanwhile, hosts a long-running and highly rated REU Summer Intern program as well as many visiting graduate students. The CfA estimates that roughly 10% of the professional astrophysics community in the United States spent at least a portion of their career or education there.

The CfA is either a lead or major partner in the operations of the Fred Lawrence Whipple Observatory, the Submillimeter Array, MMT Observatory, the South Pole Telescope, VERITAS, and a number of other smaller ground-based telescopes. The CfA’s 2019-2024 Strategic Plan includes the construction of the Giant Magellan Telescope as a driving priority for the Center.

CFA Harvard Smithsonian Submillimeter Array on Mauna Kea, Hawai’i, Altitude 4,205 m (13,796 ft).

South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including The University of Chicago ; The University of California-Berkeley ; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; The University of Colorado- Boulder; McGill (CA) University, The University of Illinois, Urbana-Champaign; The University of California- Davis; Ludwig Maximilians Universität München(DE); DOE’s Argonne National Laboratory; and The National Institute for Standards and Technology.

Along with the Chandra X-ray Observatory, the CfA plays a central role in a number of space-based observing facilities, including the recently launched Parker Solar Probe, Kepler Space Telescope, the Solar Dynamics Observatory (SDO), and HINODE. The CfA, via the Smithsonian Astrophysical Observatory, recently played a major role in the Lynx X-ray Observatory, a NASA-Funded Large Mission Concept Study commissioned as part of the 2020 Decadal Survey on Astronomy and Astrophysics (“Astro2020”). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra.

NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker. The Johns Hopkins University Applied Physics Lab.

National Aeronautics and Space Administration Solar Dynamics Observatory.

Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構] (JP)/National Aeronautics and Space Administration HINODE spacecraft.

SAO is one of the 13 stakeholder institutes for the Event Horizon Telescope Board, and the CfA hosts its Array Operations Center. In 2019, the project revealed the first direct image of a black hole.

Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via The Event Horizon Telescope Collaboration released on 10 April 2019 via National Science Foundation.

The result is widely regarded as a triumph not only of observational radio astronomy, but of its intersection with theoretical astrophysics. Union of the observational and theoretical subfields of astrophysics has been a major focus of the CfA since its founding.

In 2018, the CfA rebranded, changing its official name to the “Center for Astrophysics | Harvard & Smithsonian” in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. Today, the CfA receives roughly 70% of its funding from NASA, 22% from Smithsonian federal funds, and 4% from the National Science Foundation. The remaining 4% comes from contributors including the United States Department of Energy, the Annenberg Foundation, as well as other gifts and endowments.

From The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE): “The dance of supermassive black holes”

From The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie](DE)

2.23.23

Contacts
Dr. Stefanie Komossa
Max Planck Institute for Radio Astronomy, Bonn
+49 228 525-386
skomossa@mpifr-bonn.mpg.de

Dr. Alex Kraus
Max Planck Institute for Radio Astronomy, Bonn
+49 2257 301-101
akraus@mpifr-bonn.mpg.de

Prof. Dr. Dirk Grupe
+1 859 572-6549
Northern Kentucky University
gruped1@nku.edu

Dr. Norbert Junkes
Press and Public Outreach
MPG Institute for Radio Astronomy, Bonn
+49 228 525-399
njunkes@mpifr-bonn.mpg.de

Large-scale observational campaign provides new insights into an assumed black hole binary at the centre of the active galaxy OJ 287. A long-term study with data from four telescopes, ranging from radio to high energy frequencies, has penetrated to the core of the much-discussed active galaxy OJ 287, revealing further details about its interior. The results of the international team, led by Stefanie Komossa of the MPG Institute for Radio Astronomy, strengthen the evidence for a binary black hole system and place the primary black hole back on the scale.

The left panel shows a deep ultraviolet image, centered on OJ 287. The image was taken with the spaceborne Swift-Telescope.

National Aeronautics and Space Administration Neil Gehrels Swift X-ray, and UV/Visible light Observatory.

The source of the ultraviolet light is the nucleus of the active galaxy OJ 287, which cannot be further resolved with this telescope. The right panel depicts an artist’s view of the nucleus, including the disk of matter, the jet, and the assumed pair of black holes. The secondary black hole is orbiting the more massive one. © S. Komossa et al.; NASA/JPL-Caltech.

Blazars are a special class of active galaxies characterized by high activity and extreme luminosity. The driving engines of these galaxies are black holes hidden inside their cores, millions to billions of times heavier than our Sun. Through the course of the history of the universe, these engines were fueled especially when galaxies collided. The subsequent merger of the galaxies created supermassive binary black holes. The study of such black-hole pairs reveals a lot about the evolution of galaxies and the growth of black holes.

Black hole on the scale

OJ 287 is one of the best candidates to host a compact supermassive binary black hole. One indication of this is the exceptional bursts of radiation produced by processes at the centre of the galaxy, which repeat every 11 to 12 years. Strictly speaking, each outburst consists of two peaks separated by roughly one year. These repeating outbursts are so remarkable that several different binary models have been proposed and discussed in the literature to explain them. The team led by Stefanie Komossa at the Max Planck Institute for Radio Astronomy has now revised the previously favored model by carrying out an unprecedented and systematic observational campaign. In the process, the researchers have also directly determined the mass of the primary black hole for the first time. At 100 million solar masses, it is probably about a hundred times smaller than previously thought. The new estimate of the black hole mass also seems to explain the entire history of OJ 287’s radiation outbursts, which have now been mapped in great detail.

Unveiling the invisible

The galaxy OJ 287 is too distant for telescopes to resolve the compact nucleus around the suspected black holes. However, since this region dominates the brightness of the whole galaxy, the radiation emerging from the core is both easily detectable on Earth and allows astronomers to reconstruct, with some limitations, the processes hidden inside the bright core. To do this, it helps to know the underlying processes. Matter from a disk surrounding the black hole that drifts inward loses gravitational energy in the form of optical and ultraviolet radiation. A jet launched from the surroundings of the central engine accelerates particles outwards. This often highly relativistic stream of matter emits intense radiation ranging from the radio to the X-rays and gamma-rays.

Two radio telescopes, the 100-metre Effelsberg radio telescope in Germany and the Submillimetre-Array in Hawaii, and two satellite observatories were used for the observations. Among the latter, Fermi covers gamma-ray frequencies, while the Neil-Gehrels-Swift Observatory [above] observes optical, UV and X-ray frequencies.

The MPG Institute for Radio Astronomy[MPG Institut für Radioastronomie](DE)Effelsberg Radio Telescope- a radio telescope in the Ahr Hills (part of the Eifel) in Bad Münstereifel(DE).

CFA Harvard Smithsonian Submillimeter Array on Mauna Kea, Hawai’i, Altitude 4205 m (13796 ft).

National Aeronautics and Space Administration Fermi Gamma-Ray Large Area Telescope.

National Aeronautics and Space Administration Fermi Gamma Ray Space Telescope.

“OJ 287 is an excellent laboratory for studying the physical processes that reign in one of the most extreme astrophysical environments: disks and jets of matter in the immediate vicinity of one or two supermassive black holes”, says Stefanie Komossa from the MPG Institute for Radio Astronomy, the leading author of the two studies presented here. “Therefore, we initiated the project Momo („Multiwavelength Observations and Modelling of OJ 287“). It consists of high-cadence observations of OJ 287 at more than 14 frequencies from the radio to the high energy regime lasting for years, plus dedicated follow-ups at multiple ground- and space-based facilities when the blazar is found at exceptional states.”

The outbursts of OJ 287 can be explained by the model of a binary black hole system, in particular by the motion of the second, lower-mass black hole orbiting the primary one. On its inclined orbit, it disturbs either the jet or the disk of matter, thus causing OJ 287’s periodic bursts. Measurements with the 100-metre Effelsberg radio telescope attribute the most recent burst directly to the jet. It is like looking into a glaring spotlight that outshines everything behind it.

Strong evidence for two supermassive black holes in the core

The state-of-the-art model describing the processes in the centre of OJ 287 assumed a primary black hole ten billion times heavier than the Sun. According to this model, the next outburst would have been due in October 2022. The actual data did not confirm this prediction. Instead, thanks to the dense coverage of the Momo campaign, the astronomers discovered this outburst much earlier, between 2016 and 2017. The previously favored model was therefore falsified. The researchers then reassessed the mass of the primary black hole. It turns out to be a hundred times lighter than previously thought. As a result, the orbit of the secondary black hole around the primary black hole should wobble much less. This behavior has direct implications for the predicted outbursts, which are now consistent with both historical and recent measurements. “This result is very important, as the mass is a key parameter in the models that study the evolution of this binary system: How far are the black holes separated, how quickly will they merge, how strong is their gravitational wave signal?” says Dirk Grupe of the Northern Kentucky University, a co-author of both studies.

Gravitational waves and a photograph?

The Momo results make the authors optimistic that future space-based observatories will be able to detect gravitational waves from this or similar binary systems. It may even be possible to spatially resolve the two black holes in OJ 287 with a large network of radio telescopes, such as the Event Horizon Telescope known from the media or the Square Kilometre Array still under construction. This would be the first direct detection of a close system of two supermassive black holes in the centre of a galaxy.

MNRAS
The Astrophysical Journal

Fig. 1.

Multifrequency radio light curves of OJ 287 between 2015 December and 2022 June obtained with the Effelsberg telescope in the course of the MOMO program. Note that some receivers and/or frequencies have slightly changed in the course of the monitoring. See Table 1 for details in the science paper.

Fig. 2.

SMA radio light curve of OJ 287 between 2015 October and 2022
June (filled circles: 1.3 mm band, open green circles: 1.1 mm band, open blue
circles: 870 μm band).

For further images see the science paper.

Astronomical Notes
See the science paper for instructive material with images.

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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MPIFR campus

Effelsberg Radio Telescope- a radio telescope in the Ahr Hills (part of the Eifel) in Bad Münstereifel(DE)

The MPG Institute for Radio Astronomy [MPG Institut für Radioastronomie] (DE) is located in Bonn, Germany. It is one of 80 institutes in the MPG Society.

By combining the already existing radio astronomy faculty of the University of Bonn led by Otto Hachenberg with the new MPG institute the MPG Institute for Radio Astronomy was formed. In 1972 the 100-m radio telescope in Effelsberg was opened. The institute building was enlarged in 1983 and 2002.

The institute was founded in 1966 by the MPG Society as the “MPG Institut für Radioastronomie (MPIfR) (DE)”.

The foundation of the institute was closely linked to plans in the German astronomical community to construct a competitive large radio telescope in (then) West Germany. In 1964, Professors Friedrich Becker, Wolfgang Priester and Otto Hachenberg of the Astronomische Institute der Universität Bonn submitted a proposal to the Stiftung Volkswagenwerk for the construction of a large fully steerable radio telescope.

In the same year the Stiftung Volkswagenwerk approved the funding of the telescope project but with the condition that an organization should be found, which would guarantee the operations. It was clear that the operation of such a large instrument was well beyond the possibilities of a single university institute.

Already in 1965 the MPG Society decided in principle to found the MPG Institut für Radioastronomie. Eventually, after a series of discussions, the institute was officially founded in 1966.

MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

According to its primary goal, the MPG Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) MPG Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

The MPG Institutes focus on excellence in research. The MPG Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the MPG institutes fifth worldwide in terms of research published in Nature journals (after Harvard University, The Massachusetts Institute of Technology, Stanford University and The National Institutes of Health). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by The Chinese Academy of Sciences [中国科学院](CN), The Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the MPG Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

The MPG Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.

History

The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.

The MPG Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the MPG Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and The DOE’s Argonne National Laboratory.

The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.

MPG Institutes and research groups

The MPG Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
The MPG Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.

Internally, MPG Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.

In addition, there are several associated institutes:
International Max Planck Research Schools
Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:

• Cologne Graduate School of Ageing Research, Cologne
• International Max Planck Research School for Intelligent Systems, at the Max Planck Institute for Intelligent Systems located in Tübingen and Stuttgart
• International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
• International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
• International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPI for Astronomy
• International Max Planck Research School for Astrophysics, Garching at the MPI for Astrophysics
• International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
• International Max Planck Research School for Computer Science, Saarbrücken
• International Max Planck Research School for Earth System Modeling, Hamburg
• International Max Planck Research School for Elementary Particle Physics, Munich, at the MPI for Physics
• International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the Max Planck Institute for Terrestrial Microbiology
• International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
• International Max Planck Research School “From Molecules to Organisms”, Tübingen at the Max Planck Institute for Developmental Biology
• International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
• International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPI for Gravitational Physics
• International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the Max Planck Institute for Heart and Lung Research
• International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
• International Max Planck Research School for Language Sciences, Nijmegen
• International Max Planck Research School for Neurosciences, Göttingen
• International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
• International Max Planck Research School for Marine Microbiology (MarMic), joint program of the Max Planck Institute for Marine Microbiology in Bremen, the University of Bremen, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
• International Max Planck Research School for Maritime Affairs, Hamburg
• International Max Planck Research School for Molecular and Cellular Biology, Freiburg
• International Max Planck Research School for Molecular and Cellular Life Sciences, Munich
• International Max Planck Research School for Molecular Biology, Göttingen
• International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
• International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster and the Max Planck Institute for Molecular Biomedicine
• International Max Planck Research School on Multiscale Bio-Systems, Potsdam
• International Max Planck Research School for Organismal Biology, at the University of Konstanz and the Max Planck Institute for Ornithology
• International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion
• International Max Planck Research School for Science and Technology of Nano-Systems, Halle at Max Planck Institute of Microstructure Physics
• International Max Planck Research School for Solar System Science at the University of Göttingen hosted by MPI for Solar System Research
• International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPI for Radio Astronomy (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
• International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
• International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at Max Planck Institute for Iron Research GmbH
• International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

Max Planck Schools

• Max Planck School of Cognition
• Max Planck School Matter to Life
• Max Planck School of Photonics

Max Planck Center

• The Max Planck Centre for Attosecond Science (MPC-AS), POSTECH Pohang
• The Max Planck POSTECH Center for Complex Phase Materials, POSTECH Pohang

Max Planck Institutes

Among others:
• Max Planck Institute for Neurobiology of Behavior – caesar, Bonn
• Max Planck Institute for Aeronomics in Katlenburg-Lindau was renamed to Max Planck Institute for Solar System Research in 2004;
• Max Planck Institute for Biology in Tübingen was closed in 2005;
• Max Planck Institute for Cell Biology in Ladenburg b. Heidelberg was closed in 2003;
• Max Planck Institute for Economics in Jena was renamed to the Max Planck Institute for the Science of Human History in 2014;
• Max Planck Institute for Ionospheric Research in Katlenburg-Lindau was renamed to Max Planck Institute for Aeronomics in 1958;
• Max Planck Institute for Metals Research, Stuttgart
• Max Planck Institute of Oceanic Biology in Wilhelmshaven was renamed to Max Planck Institute of Cell Biology in 1968 and moved to Ladenburg 1977;
• Max Planck Institute for Psychological Research in Munich merged into the Max Planck Institute for Human Cognitive and Brain Sciences in 2004;
• Max Planck Institute for Protein and Leather Research in Regensburg moved to Munich 1957 and was united with the Max Planck Institute for Biochemistry in 1977;
• Max Planck Institute for Virus Research in Tübingen was renamed as Max Planck Institute for Developmental Biology in 1985;
• Max Planck Institute for the Study of the Scientific-Technical World in Starnberg (from 1970 until 1981 (closed)) directed by Carl Friedrich von Weizsäcker and Jürgen Habermas.
• Max Planck Institute for Behavioral Physiology
• Max Planck Institute of Experimental Endocrinology
• Max Planck Institute for Foreign and International Social Law
• Max Planck Institute for Physics and Astrophysics
• Max Planck Research Unit for Enzymology of Protein Folding
• Max Planck Institute for Biology of Ageing

From The Royal Astronomical Society (UK): “New discovery sheds light on very early supermassive black holes”

From The Royal Astronomical Society (UK)

2.22.23

Media Contacts

Gurjeet Kahlon
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk

Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877699
press@ras.ac.uk

Science Contacts

Dr Ryan Endsley
McDonald Observatory, The University of Texas at Austin
ryan.endsley@austin.utexas.edu

Professor Dan Stark
University of Arizona
dpstark@arizona.edu

This system consists of a pair of galaxies, dubbed IC 694 and NGC 3690, which made a close pass some 700 million years ago. As a result of this interaction, the system underwent a fierce burst of star formation. In the last fifteen years or so six supernovae have popped off in the outer reaches of the galaxy, making this system a distinguished supernova factory. Credit: A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)/NASA/ESA/ the Hubble Heritage Team (STScI/AURA) Licence type Attribution (CC BY 4.0)

Astronomers from The University of Texas-Austin and The University of Arizona have discovered a rapidly growing black hole in one of the most extreme galaxies known in the very early Universe. The discovery of the galaxy and the black hole at its centre provides new clues on the formation of the very first supermassive black holes. The new work is published in MNRAS [below].

Using observations taken with the Atacama Large Millimeter Array (ALMA), a radio observatory sited in Chile, the team have determined that the galaxy, named COS-87259, containing this new supermassive black hole is very extreme, forming stars at a rate 1000 times that of our own Milky Way and containing over a billion solar masses worth of interstellar dust.

The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europäische Südsternwarte](EU)(CL)/National Radio Astronomy Observatory/National Astronomical Observatory of Japan(JP) ALMA Observatory (CL).

The galaxy shines bright from both this intense burst of star formation and the growing supermassive black hole at its centre.

The black hole is considered to be a new type of primordial black hole – one heavily enshrouded by cosmic “dust”, causing nearly all of its light to be emitted in the mid-infrared range of the electromagnetic spectrum. The researchers have also found that this growing supermassive black hole (frequently referred to as an active galactic nucleus) is generating a strong jet of material moving at near light speed through the host galaxy.

Today, black holes with masses millions to billions of times greater than that of our own Sun sit at the centre of nearly every galaxy. How these supermassive black holes first formed remains a mystery for scientists, particularly because several of these objects have been found when the Universe was very young. Because the light from these sources takes so long to reach us, we see them as they existed in the past; in this case, just 750 million years after the Big Bang, which is approximately 5% of the current age of the Universe.

What is particularly astonishing about this new object is that it was identified over a relatively small patch of the sky typically used to detect similar objects – less than 10 times the size of the full moon – suggesting there could be thousands of similar sources in the very early Universe. This was completely unexpected from previous data.

The only other class of supermassive black holes we knew about in the very early Universe are quasars, which are active black holes that are relatively unobscured by cosmic dust. These quasars are extremely rare at distances similar to COS-87259, with only a few tens located over the full sky. The surprising discovery of COS-87259 and its black hole raises several questions about the abundance of very early supermassive black holes, as well as the types of galaxies in which they typically form.

Ryan Endsley, the lead author of the paper and now a Postdoctoral Fellow at The University of Texas-Austin, says “These results suggest that very early supermassive black holes were often heavily obscured by dust, perhaps as a consequence of the intense star formation activity in their host galaxies. This is something others have been predicting for a few years now, and it’s really nice to see the first direct observational evidence supporting this scenario.”

Similar types of objects have been found in the more local, present-day Universe, such as Arp 299 [?] shown here.

In this system, two galaxies are crashing together generating an intense starburst as well as heavy obscuration of the growing supermassive black hole in one of the two galaxies.

Endsley adds, “While nobody expected to find this kind of object in the very early Universe, its discovery takes a step towards building a much better understanding of how billion solar mass black holes were able to form so early on in the lifetime of the Universe, as well how the most massive galaxies first evolved.”

MNRAS
See the science paper for instructive material with images.

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Please help promote STEM in your local schools.

Stem Education Coalition

The Royal Astronomical Society is a learned society and charity that encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. Its headquarters are in Burlington House, on Piccadilly in London. The society has over 4,000 members (“Fellows”), most of them professional researchers or postgraduate students. Around a quarter of Fellows live outside the UK.

The society holds monthly scientific meetings in London, and the annual National Astronomy Meeting at varying locations in the British Isles. The Royal Astronomical Society publishes the scientific journals MNRAS and Geophysical Journal International, along with the trade magazine Astronomy & Geophysics.

The Royal Astronomical Society maintains an astronomy research library, engages in public outreach and advises the UK government on astronomy education. The society recognizes achievement in Astronomy and Geophysics by issuing annual awards and prizes, with its highest award being the Gold Medal of The Royal Astronomical Society. The Royal Astronomical Society is the UK adhering organization to the International Astronomical Union and a member of the UK Science Council.

The society was founded in 1820 as the Astronomical Society of London to support astronomical research. At that time, most members were ‘gentleman astronomers’ rather than professionals. It became the Royal Astronomical Society in 1831 on receiving a Royal Charter from William IV. A Supplemental Charter in 1915 opened up the fellowship to women.

One of the major activities of the RAS is publishing refereed journals. It publishes two primary research journals, the Monthly Notices of the Royal Astronomical Society [MNRAS] in astronomy and (in association with The German Geophysical Society [Deutsche Geophysikalische Gesellschaft e.V. ](DE)]) the Geophysical Journal International in geophysics. It also publishes the magazine A&G which includes reviews and other articles of wide scientific interest in a ‘glossy’ format. The full list of journals published (both currently and historically) by the RAS, with abbreviations as used for the NASA ADS bibliographic codes is:

Memoirs of the Royal Astronomical Society (MmRAS): 1822–1977[3]
Monthly Notices of the Royal Astronomical Society (MNRAS): Since 1827
Geophysical Supplement to Monthly Notices (MNRAS): 1922–1957
Geophysical Journal (GeoJ): 1958–1988
Geophysical Journal International (GeoJI): Since 1989 (volume numbering continues from GeoJ)
Quarterly Journal of the Royal Astronomical Society (QJRAS): 1960–1996
Astronomy & Geophysics (A&G): Since 1997 (volume numbering continues from QJRAS)

Associated groups

The RAS sponsors topical groups, many of them in interdisciplinary areas where the group is jointly sponsored by another learned society or professional body:

The Astrobiology Society of Britain (UK) (with The NASA Astrobiology Institute)
The Astroparticle Physics Group (with The Institute of Physics – London (UK))
The Astrophysical Chemistry Group (with The Royal Society of Chemistry)
The British Geophysical Association (with The Geological Society of London (UK).
The Magnetosphere Ionosphere and Solar-Terrestrial group (UK)
The UK Planetary Forum
The UK Solar Physics group

From The Johns Hopkins University Via The “HUB” : “Simulations show aftermath of black hole collision”

From The Johns Hopkins University

Via

The “HUB”

2.22.23
Roberto Molar Candanosa

New simulations of two black holes colliding near the speed of light reveal the mysterious physics of what one astrophysicist calls “one of the most violent events you can imagine in the universe.”

“It’s a bit of a crazy thing to blast two black holes head-on very close to the speed of light,” said Thomas Helfer, a postdoctoral fellow at Johns Hopkins University who produced the simulations. “The gravitational waves associated with the collision might look anticlimactic, but this is one of the most violent events you can imagine in the universe.”

The work, which appears today in Physical Review Letters [below], is the first detailed look at the aftermath of such a cataclysmic clash, and shows how a remnant black hole would form and send gravitational waves through the cosmos.

Simulations Show Aftermath of Black Hole Collision.

Black hole mergers are one of the few events in the universe energetic enough to produce detectable gravitational waves, which carry energy produced by massive cosmic collisions. Like ripples in a pond, these waves flow through the universe distorting space and time. But unlike waves traveling through water, they are extremely tiny, and propagate through “spacetime,” the mind-bending concept that combines the three dimensions of space with the idea of time.

“If a gravitational wave goes through me, it makes me a little thinner and a little taller, and then a little shorter and a little fatter,” said co-author Emanuele Berti, a Johns Hopkins physicist. “But the amount by which it does that is about 100,000 times smaller than the size of an atomic nucleus.”

Physicists have studied the waves emitted after black holes merge by simplifying general relativity—Einstein’s theory of how gravity works—using equations that ignore subtle, but important, gravitational effects of the merger. Berti thinks that approach is biased because it relies on “linear approximations,” the assumption that the gravitational waves produced during the merger are weak.

Although it is nearly impossible for black holes to collide at such extreme speeds, simulating such a crash produced signals strong enough for the team to detect nonlinearities, or gravitational effects that can’t be found with the simplified version of the theory. The findings suggest black hole mergers cannot be studied with linearized equations and that current models of these events need to be tweaked, if not changed altogether.

“General relativity is nonlinear, which means that the gravitational waves themselves will also produce more gravitational waves,” said Mark Ho-Yeuk Cheung, a Johns Hopkins doctoral physics student who led the research.

The team also spotted these so-called nonlinearities by analyzing simulations of two black holes merging after orbiting each other, a scenario that more realistically represents what happens in the universe. A study of the same simulations by an independent group of researchers at Caltech also appears in today’s Physical Review Letters [below] and finds similar results.

“It’s kind of a big deal because we cannot forget about the complications if we really want to understand black holes,” Cheung said. “Einstein’s theory is a beast; the equations are really complicated.”

The paper’s authors include several other Johns Hopkins affilates: Vishal Baibhav of Northwestern University, and Kaze Wong of the Flatiron Institute, who both earned PhDs in physics from Johns Hopkins in 2021; and Roberto Cotesta, a postdoctoral fellow in the Department of Physics and Astronomy.

Physical Review Letters [JHU]

Evidence for nonlinear modes in the ringdown stage of the gravitational waveform produced by the merger of two comparable-mass black holes. We consider both the coalescence of black hole binaries in quasicircular orbits and high-energy, head-on black hole collisions. The presence of nonlinear modes in the numerical simulations confirms that general-relativistic nonlinearities are important and must be considered in gravitational-wave data analysis.

Physical Review Letters [Caltech]
The gravitational wave strain emitted by a perturbed black hole (BH) ringing down is typically modeled analytically using first-order BH perturbation theory. In this Letter, we show that second-order effects are necessary for modeling ringdowns from BH merger simulations. Focusing on the strain’s (ℓ,m)=(4,4) angular harmonic, we show the presence of a quadratic effect across a range of binary BH mass ratios that agrees with theoretical expectations. We find that the quadratic (4,4) mode’s amplitude exhibits quadratic scaling with the fundamental (2,2) mode—its parent mode. The nonlinear mode’s amplitude is comparable to or even larger than that of the linear (4,4) mode. Therefore, correctly modeling the ringdown of higher harmonics—improving mode mismatches by up to 2 orders of magnitude—requires the inclusion of nonlinear effects.

See the full article here.

See also the full article from Caltech here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Johns Hopkins University campus

Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

The Johns Hopkins University is a private research university in Baltimore, Maryland. Founded in 1876, the university was named for its first benefactor, the American entrepreneur and philanthropist Johns Hopkins. His $7 million bequest (approximately $147.5 million in today’s currency)—of which half financed the establishment of the Johns Hopkins Hospital—was the largest philanthropic gift in the history of the United States up to that time. Daniel Coit Gilman, who was inaugurated as the institution’s first president on February 22, 1876, led the university to revolutionize higher education in the U.S. by integrating teaching and research. Adopting the concept of a graduate school from Germany’s historic Ruprecht Karl University of Heidelberg, [Ruprecht-Karls-Universität Heidelberg] (DE), Johns Hopkins University is considered the first research university in the United States. Over the course of several decades, the university has led all U.S. universities in annual research and development expenditures. In fiscal year 2016, Johns Hopkins spent nearly $2.5 billion on research. The university has graduate campuses in Italy, China, and Washington, D.C., in addition to its main campus in Baltimore.

Johns Hopkins is organized into 10 divisions on campuses in Maryland and Washington, D.C., with international centers in Italy and China. The two undergraduate divisions, the Zanvyl Krieger School of Arts and Sciences and the Whiting School of Engineering, are located on the Homewood campus in Baltimore’s Charles Village neighborhood. The medical school, nursing school, and Bloomberg School of Public Health, and Johns Hopkins Children’s Center are located on the Medical Institutions campus in East Baltimore. The university also consists of the Peabody Institute, Applied Physics Laboratory, Paul H. Nitze School of Advanced International Studies, School of Education, Carey Business School, and various other facilities.

Johns Hopkins was a founding member of the American Association of Universities. As of October 2019, 39 Nobel laureates and 1 Fields Medalist have been affiliated with Johns Hopkins. Founded in 1883, the Blue Jays men’s lacrosse team has captured 44 national titles and plays in the Big Ten Conference as an affiliate member as of 2014.

Research

The opportunity to participate in important research is one of the distinguishing characteristics of Hopkins’ undergraduate education. About 80 percent of undergraduates perform independent research, often alongside top researchers. In FY 2013, Johns Hopkins received $2.2 billion in federal research grants—more than any other U.S. university for the 35th consecutive year. Johns Hopkins has had seventy-seven members of the Institute of Medicine, forty-three Howard Hughes Medical Institute Investigators, seventeen members of the National Academy of Engineering, and sixty-two members of the National Academy of Sciences. As of October 2019, 39 Nobel Prize winners have been affiliated with the university as alumni, faculty members or researchers, with the most recent winners being Gregg Semenza and William G. Kaelin.

Between 1999 and 2009, The Johns Hopkins University was among the most cited institutions in the world. It attracted nearly 1,222,166 citations and produced 54,022 papers under its name, ranking No. 3 globally [after Harvard University and the Max Planck Society (DE)] in the number of total citations published in Thomson Reuters-indexed journals over 22 fields in America.

In FY 2000, Johns Hopkins received $95.4 million in research grants from the National Aeronautics and Space Administration, making it the leading recipient of NASA research and development funding. In FY 2002, Hopkins became the first university to cross the $1 billion threshold on either list, recording $1.14 billion in total research and $1.023 billion in federally sponsored research. In FY 2008, Johns Hopkins University performed $1.68 billion in science, medical and engineering research, making it the leading U.S. academic institution in total R&D spending for the 30th year in a row, according to a National Science Foundation ranking. These totals include grants and expenditures of JHU’s Applied Physics Laboratory in Laurel, Maryland.

The Johns Hopkins University also offers the “Center for Talented Youth” program—a nonprofit organization dedicated to identifying and developing the talents of the most promising K-12 grade students worldwide. As part of the Johns Hopkins University, the “Center for Talented Youth” or CTY helps fulfill the university’s mission of preparing students to make significant future contributions to the world. The Johns Hopkins Digital Media Center (DMC) is a multimedia lab space as well as an equipment, technology and knowledge resource for students interested in exploring creative uses of emerging media and use of technology.

In 2013, the Bloomberg Distinguished Professorships program was established by a $250 million gift from Michael Bloomberg. This program enables the university to recruit fifty researchers from around the world to joint appointments throughout the nine divisions and research centers. For The American Academy of Arts and Sciences each professor must be a leader in interdisciplinary research and be active in undergraduate education. Directed by Vice Provost for Research Denis Wirtz, there are currently thirty-two Bloomberg Distinguished Professors at the university, including three Nobel Laureates, eight fellows of the American Association for the Advancement of Science, ten members of the American Academy of Arts and Sciences, and thirteen members of the National Academies.

From The California Institute of Technology: “Physicists Create New Model of Ringing Black Holes”

From The California Institute of Technology

2.21.23
Whitney Clavin
(626) 395‑1944
wclavin@caltech.edu

An artist’s visualization of two black holes colliding. These cosmic collisions create ripples in the fabric of space and time, which scientists are able to detect with the LIGO detectors [below] in Washington and Louisiana. Credit: SXS – Simulating eXtreme Spacetimes Black Holes merging

New analysis shows “nonlinear” effects contained in gravitational waves.

This illustration depicts the ringdown phase of a black hole that has recently formed from the collision of two smaller black holes. A new model for this phase of black hole mergers shows the previously known linear effects (blue) and the newly discovered nonlinear effects (orange). The nonlinear effects, which have their own unique frequency, are created by the linear effects near the black hole’s light ring before they escape in the form of gravitational waves.
Credit: L. Stein (University of Mississippi)/K. Mitman (Caltech)

When two black holes collide into each other to form a new bigger black hole, they violently roil spacetime around them, sending ripples called gravitational waves outward in all directions. Previous studies of black hole collisions modeled the behavior of the gravitational waves using what is known as linear math, which means that the gravitational waves rippling outward did not influence, or interact, with each other. Now, a new analysis has modeled the same collisions in more detail and revealed so-called nonlinear effects.

“Nonlinear effects are what happens when waves on the beach crest and crash” says Keefe Mitman, a Caltech graduate student who works with Saul Teukolsky (PhD ’74), the Robinson Professor of Theoretical Astrophysics at Caltech with a joint appointment at Cornell University. “The waves interact and influence each other rather than ride along by themselves. With something as violent as a black hole merger, we expected these effects but had not seen them in our models until now. New methods for extracting the waveforms from our simulations have made it possible to see the nonlinearities.”

Keefe Mitman explains what it means to find nonlinear effects in models of black hole mergers.

The research, published in the journal Physical Review Letters [below], come from a team of researchers at Caltech, Columbia University, University of Mississippi, Cornell University, and the MPG Institute for Gravitational Physics.

Physical Review Letters
Fig 1.

Relationship between the peak amplitudes of the linear (2, 2, 0) and the quadratic (2, 2, 0) × (2, 2, 0) QNMs (top panels) as well as the linear (4, 4, 0) QNM (bottom panels), at different model start times u0. Colors show different mass ratios q, and circles and triangles denote systems with remnant dimensionless spin χf ≈ 0.5 and χf ≈ 0.7, respectively. Each blue curve is a pure quadratic fit with start time u0, and the shaded region brackets every one of the individual fits.

For further illustrations see the science paper.

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Please help promote STEM in your local schools.

Stem Education Coalition

Caltech campus

The California Institute of Technology is a private research university in Pasadena, California. The university is known for its strength in science and engineering, and is one among a small group of institutes of technology in the United States which is primarily devoted to the instruction of pure and applied sciences.

The California Institute of Technology was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910 and the college assumed its present name in 1920. In 1934, The California Institute of Technology was elected to the Association of American Universities, and the antecedents of National Aeronautics and Space Administration ‘s Jet Propulsion Laboratory, which The California Institute of Technology continues to manage and operate, were established between 1936 and 1943 under Theodore von Kármán.

The California Institute of Technology has six academic divisions with strong emphasis on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. First-year students are required to live on campus, and 95% of undergraduates remain in the on-campus House System at The California Institute of Technology. Although The California Institute of Technology has a strong tradition of practical jokes and pranks, student life is governed by an honor code which allows faculty to assign take-home examinations. The The California Institute of Technology Beavers compete in 13 intercollegiate sports in the NCAA Division III’s Southern California Intercollegiate Athletic Conference (SCIAC).

As of October 2020, there are 76 Nobel laureates who have been affiliated with The California Institute of Technology, including 40 alumni and faculty members (41 prizes, with chemist Linus Pauling being the only individual in history to win two unshared prizes). In addition, 4 Fields Medalists and 6 Turing Award winners have been affiliated with The California Institute of Technology. There are 8 Crafoord Laureates and 56 non-emeritus faculty members (as well as many emeritus faculty members) who have been elected to one of the United States National Academies. Four Chief Scientists of the U.S. Air Force and 71 have won the United States National Medal of Science or Technology. Numerous faculty members are associated with the Howard Hughes Medical Institute as well as National Aeronautics and Space Administration. According to a 2015 Pomona College study, The California Institute of Technology ranked number one in the U.S. for the percentage of its graduates who go on to earn a PhD.

Research

The California Institute of Technology is classified among “R1: Doctoral Universities – Very High Research Activity”. Caltech was elected to The Association of American Universities in 1934 and remains a research university with “very high” research activity, primarily in STEM fields. The largest federal agencies contributing to research are National Aeronautics and Space Administration; National Science Foundation; Department of Health and Human Services; Department of Defense, and Department of Energy.

In 2005, The California Institute of Technology had 739,000 square feet (68,700 m^2) dedicated to research: 330,000 square feet (30,700 m^2) to physical sciences, 163,000 square feet (15,100 m^2) to engineering, and 160,000 square feet (14,900 m^2) to biological sciences.

In addition to managing NASA-JPL/Caltech , The California Institute of Technology also operates the Caltech Palomar Observatory; The Owens Valley Radio Observatory;the Caltech Submillimeter Observatory; the W. M. Keck Observatory at the Mauna Kea Observatory; the Laser Interferometer Gravitational-Wave Observatory at Livingston, Louisiana and Hanford, Washington; and Kerckhoff Marine Laboratory in Corona del Mar, California. The Institute launched the Kavli Nanoscience Institute at The California Institute of Technology in 2006; the Keck Institute for Space Studies in 2008; and is also the current home for the Einstein Papers Project. The Spitzer Science Center, part of the Infrared Processing and Analysis Center located on The California Institute of Technology campus, is the data analysis and community support center for NASA’s Spitzer Infrared Space Telescope [no longer in service].

Caltech Palomar Observatory. Credit:The California Institute of Technology, Altitude 1,713 m (5,620 ft), located in San Diego County, California.

California Institute of Technology The Owens Valley Radio Observatory, Owens Valley, California, Altitude 1,222 m (4,009 ft). Credit: Caltech.

W.M. Keck Observatory two ten meter telescopes operated by California Institute of Technology and The University of California, at Mauna Kea Observatory, Hawai’i, altitude 4,207 m (13,802 ft). Credit: Caltech.

Caltech /MIT Advanced aLigo. Credit: Caltech.

Caltech/MIT Advanced aLigo Hanford, WA installation. Credit: Caltech.

Caltech/MIT Advanced aLigo detector installation Livingston, LA. Credit: Caltech.

The California Institute of Technology partnered with University of California-Los Angeles to establish a Joint Center for Translational Medicine (UCLA-Caltech JCTM), which conducts experimental research into clinical applications, including the diagnosis and treatment of diseases such as cancer.

The California Institute of Technology operates several Total Carbon Column Observing Network stations as part of an international collaborative effort of measuring greenhouse gases globally. One station is on campus.

From Yale University via “Science Alert (AU)” : “A Fleeing Black Hole Was Found Leaving a Trail of Newborn Stars in Its Wake”

From Yale University

Via

“Science Alert (AU)”

2.15.23
Michelle Starr

A strange streak emerging from a distant galaxy. The galaxy is on the left; the streak is at its brightest at the farthest distance from the galaxy. (van Dokkum et al.)

A trail found in the gas surrounding a distant galaxy could be the smoking gun pointing to a runaway supermassive black hole.

Based on an analysis of light that has traveled for more than 7.5 billion years to reach us, a team of astronomers has presented evidence of a colossal object ejected from its host galaxy 39 million years ago, which is now speeding across intergalactic space at 1,600 kilometers (994 miles) per second.

Although the black hole itself is invisible, its wake is not: shocks left in the tenuous intergalactic medium leave behind a trail of star formation in the compressed gas. The team’s work shows one way we could identify quiescent supermassive black holes ejected from their galaxies to zoom, invisible and untethered, through intergalactic space.

The research, led by astrophysicist Pieter van Dokkum of Yale University, has been accepted into The Astrophysical Journal Letters [below].

The idea that a supermassive black hole could be ejected from its galaxy isn’t actually that strange. In fact, astronomers have already identified what they think might be multiple supermassive black holes ejected from the centers of their galaxies (although none yet crossing into intergalactic space), and even one galaxy that appears to be missing its supermassive black hole altogether.

But those supermassive black holes all had one thing in common: they’re active, which means they’re surrounded by a cloud of material that’s falling into their gaping mouths of doom. This process generates insane amounts of heat and light, which makes them much easier to spot.

But not all black holes are active. And those that are quietly minding their business between snacks, just hanging out doing their thing, emit no light we can detect and are therefore essentially invisible to our technology.

However, something as weighty as a supermassive black hole – millions to billions of times the mass of the Sun – might still leave behind tracks we can spot. This is what van Dokkum and his colleagues proposed: that the trail of an ejected supermassive black hole might be detected in the gas that surrounds a galaxy, known as the circumgalactic medium.

The discovery was made in the course of other investigations. The researchers were using Hubble to study a much closer dwarf galaxy called RCP 28. It was in that image that they discovered something that might just be the trail of a runaway supermassive black hole.

The image revealed a bright streak pointing straight at the center of an irregular galaxy. Initially, the researchers thought it was a cosmic ray, but it showed up in both the filters used to process the images. So, in October 2022, they took follow-up images using the Keck Observatory, to calculate the redshift of the galaxy and streak. This gave them a size: the streak measures over 200,000 light-years in length.

Analysis showed that the galaxy and the streak have the same redshift, meaning that they are likely associated with each other, and the streak and galaxy have the same color. The team had never seen anything like it.

Looking more closely, they found that the streak was not uniform in color or brightness. It also shows signs of strong ionization, and shock regions. Some of the ionization could be explained by the presence of very young, hot, massive stars; that’s consistent with astrophysical shocks, which tend to compress gas and cause clumps of it to collapse under gravity, forming baby stars.

Streaks of light emerging from the centers of galaxies are not uncommon; these are usually astrophysical jets, powerful, narrow streams of plasma traveling at near light speeds, launched from the polar regions of active supermassive black holes. The streak the team found shows none of the hallmarks of an astrophysical jet, though.

It’s possible, the team speculated, that the passage of a jet could have left a trail of star formation in its wake; but the streak in the images doesn’t match any observed or simulated instance of jet-induced star formation on record.

In fact, the observed streak happens to be the very opposite of what astronomers would expect of a jet of gas; strongest at the farthest point from the galaxy, where there is less material, and narrower at greater distance, rather than spreading out like a jet.

The team believes that the best explanation is a runaway supermassive black hole, perturbing and compressing the circumgalactic medium as it travels through, leaving star formation behind.

The Astrophysical Journal Letters

These images from the Hubble’s Advanced Camera for Surveys show the linear feature that may result from a rogue SMBH. Image Credit: van Dokkum et al. 2023.

This figure from the research shows the morphology of the galaxy in F606W and F814W (Hubble filters.) The arrow indicates the direction of the linear feature. The galaxy is compact and shows irregular features, possibly indicating a recent merger and/or a connection to the linear feature. Image Credit: van Dokkum et al. 2023.

See the science paper for further images.

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Please help promote STEM in your local schools.

Stem Education Coalition

Yale University is a private Ivy League research university in New Haven, Connecticut. Founded in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and one of the nine Colonial Colleges chartered before the American Revolution. The Collegiate School was renamed Yale College in 1718 to honor the school’s largest private benefactor for the first century of its existence, Elihu Yale. Yale University is consistently ranked as one of the top universities and is considered one of the most prestigious in the nation.

Chartered by Connecticut Colony, the Collegiate School was established in 1701 by clergy to educate Congregational ministers before moving to New Haven in 1716. Originally restricted to theology and sacred languages, the curriculum began to incorporate humanities and sciences by the time of the American Revolution. In the 19th century, the college expanded into graduate and professional instruction, awarding the first PhD in the United States in 1861 and organizing as a university in 1887. Yale’s faculty and student populations grew after 1890 with rapid expansion of the physical campus and scientific research.

Yale is organized into fourteen constituent schools: the original undergraduate college, the Yale Graduate School of Arts and Sciences and twelve professional schools. While the university is governed by the Yale Corporation, each school’s faculty oversees its curriculum and degree programs. In addition to a central campus in downtown New Haven, the university owns athletic facilities in western New Haven, a campus in West Haven, Connecticut, and forests and nature preserves throughout New England. As of June 2020, the university’s endowment was valued at $31.1 billion, the second largest of any educational institution. The Yale University Library, serving all constituent schools, holds more than 15 million volumes and is the third-largest academic library in the United States. Students compete in intercollegiate sports as the Yale Bulldogs in the NCAA Division I – Ivy League.

As of October 2020, 65 Nobel laureates, five Fields Medalists, four Abel Prize laureates, and three Turing award winners have been affiliated with Yale University. In addition, Yale has graduated many notable alumni, including five U.S. Presidents, 19 U.S. Supreme Court Justices, 31 living billionaires, and many heads of state. Hundreds of members of Congress and many U.S. diplomats, 78 MacArthur Fellows, 252 Rhodes Scholars, 123 Marshall Scholars, and nine Mitchell Scholars have been affiliated with the university.

Research

Yale is a member of the Association of American Universities (AAU) and is classified among “R1: Doctoral Universities – Very high research activity”. According to the National Science Foundation , Yale spent $990 million on research and development in 2018, ranking it 15th in the nation.

Yale’s faculty include 61 members of the National Academy of Sciences , 7 members of the National Academy of Engineering and 49 members of the American Academy of Arts and Sciences . The college is, after normalization for institution size, the tenth-largest baccalaureate source of doctoral degree recipients in the United States, and the largest such source within the Ivy League.

Yale’s English and Comparative Literature departments were part of the New Criticism movement. Of the New Critics, Robert Penn Warren, W.K. Wimsatt, and Cleanth Brooks were all Yale faculty. Later, the Yale Comparative literature department became a center of American deconstruction. Jacques Derrida, the father of deconstruction, taught at the Department of Comparative Literature from the late seventies to mid-1980s. Several other Yale faculty members were also associated with deconstruction, forming the so-called “Yale School”. These included Paul de Man who taught in the Departments of Comparative Literature and French, J. Hillis Miller, Geoffrey Hartman (both taught in the Departments of English and Comparative Literature), and Harold Bloom (English), whose theoretical position was always somewhat specific, and who ultimately took a very different path from the rest of this group. Yale’s history department has also originated important intellectual trends. Historians C. Vann Woodward and David Brion Davis are credited with beginning in the 1960s and 1970s an important stream of southern historians; likewise, David Montgomery, a labor historian, advised many of the current generation of labor historians in the country. Yale’s Music School and Department fostered the growth of Music Theory in the latter half of the 20th century. The Journal of Music Theory was founded there in 1957; Allen Forte and David Lewin were influential teachers and scholars.

In addition to eminent faculty members, Yale research relies heavily on the presence of roughly 1200 Postdocs from various national and international origin working in the multiple laboratories in the sciences, social sciences, humanities, and professional schools of the university. The university progressively recognized this working force with the recent creation of the Office for Postdoctoral Affairs and the Yale Postdoctoral Association.

Notable alumni

Over its history, Yale has produced many distinguished alumni in a variety of fields, ranging from the public to private sector. According to 2020 data, around 71% of undergraduates join the workforce, while the next largest majority of 16.6% go on to attend graduate or professional schools. Yale graduates have been recipients of 252 Rhodes Scholarships, 123 Marshall Scholarships, 67 Truman Scholarships, 21 Churchill Scholarships, and 9 Mitchell Scholarships. The university is also the second largest producer of Fulbright Scholars, with a total of 1,199 in its history and has produced 89 MacArthur Fellows. The U.S. Department of State Bureau of Educational and Cultural Affairs ranked Yale fifth among research institutions producing the most 2020–2021 Fulbright Scholars. Additionally, 31 living billionaires are Yale alumni.

At Yale, one of the most popular undergraduate majors among Juniors and Seniors is political science, with many students going on to serve careers in government and politics. Former presidents who attended Yale for undergrad include William Howard Taft, George H. W. Bush, and George W. Bush while former presidents Gerald Ford and Bill Clinton attended Yale Law School. Former vice-president and influential antebellum era politician John C. Calhoun also graduated from Yale. Former world leaders include Italian prime minister Mario Monti, Turkish prime minister Tansu Çiller, Mexican president Ernesto Zedillo, German president Karl Carstens, Philippine president José Paciano Laurel, Latvian president Valdis Zatlers, Taiwanese premier Jiang Yi-huah, and Malawian president Peter Mutharika, among others. Prominent royals who graduated are Crown Princess Victoria of Sweden, and Olympia Bonaparte, Princess Napoléon.

Yale alumni have had considerable presence in U.S. government in all three branches. On the U.S. Supreme Court, 19 justices have been Yale alumni, including current Associate Justices Sonia Sotomayor, Samuel Alito, Clarence Thomas, and Brett Kavanaugh. Numerous Yale alumni have been U.S. Senators, including current Senators Michael Bennet, Richard Blumenthal, Cory Booker, Sherrod Brown, Chris Coons, Amy Klobuchar, Ben Sasse, and Sheldon Whitehouse. Current and former cabinet members include Secretaries of State John Kerry, Hillary Clinton, Cyrus Vance, and Dean Acheson; U.S. Secretaries of the Treasury Oliver Wolcott, Robert Rubin, Nicholas F. Brady, Steven Mnuchin, and Janet Yellen; U.S. Attorneys General Nicholas Katzenbach, John Ashcroft, and Edward H. Levi; and many others. Peace Corps founder and American diplomat Sargent Shriver and public official and urban planner Robert Moses are Yale alumni.

Yale has produced numerous award-winning authors and influential writers, like Nobel Prize in Literature laureate Sinclair Lewis and Pulitzer Prize winners Stephen Vincent Benét, Thornton Wilder, Doug Wright, and David McCullough. Academy Award winning actors, actresses, and directors include Jodie Foster, Paul Newman, Meryl Streep, Elia Kazan, George Roy Hill, Lupita Nyong’o, Oliver Stone, and Frances McDormand. Alumni from Yale have also made notable contributions to both music and the arts. Leading American composer from the 20th century Charles Ives, Broadway composer Cole Porter, Grammy award winner David Lang, and award-winning jazz pianist and composer Vijay Iyer all hail from Yale. Hugo Boss Prize winner Matthew Barney, famed American sculptor Richard Serra, President Barack Obama presidential portrait painter Kehinde Wiley, MacArthur Fellow and contemporary artist Sarah Sze, Pulitzer Prize winning cartoonist Garry Trudeau, and National Medal of Arts photorealist painter Chuck Close all graduated from Yale. Additional alumni include architect and Presidential Medal of Freedom winner Maya Lin, Pritzker Prize winner Norman Foster, and Gateway Arch designer Eero Saarinen. Journalists and pundits include Dick Cavett, Chris Cuomo, Anderson Cooper, William F. Buckley, Jr., and Fareed Zakaria.

In business, Yale has had numerous alumni and former students go on to become founders of influential business, like William Boeing (Boeing, United Airlines), Briton Hadden and Henry Luce (Time Magazine), Stephen A. Schwarzman (Blackstone Group), Frederick W. Smith (FedEx), Juan Trippe (Pan Am), Harold Stanley (Morgan Stanley), Bing Gordon (Electronic Arts), and Ben Silbermann (Pinterest). Other business people from Yale include former chairman and CEO of Sears Holdings Edward Lampert, former Time Warner president Jeffrey Bewkes, former PepsiCo chairperson and CEO Indra Nooyi, sports agent Donald Dell, and investor/philanthropist Sir John Templeton.

Yale alumni distinguished in academia include literary critic and historian Henry Louis Gates, economists Irving Fischer, Mahbub ul Haq, and Nobel Prize laureate Paul Krugman; Nobel Prize in Physics laureates Ernest Lawrence and Murray Gell-Mann; Fields Medalist John G. Thompson; Human Genome Project leader and National Institutes of Health director Francis S. Collins; brain surgery pioneer Harvey Cushing; pioneering computer scientist Grace Hopper; influential mathematician and chemist Josiah Willard Gibbs; National Women’s Hall of Fame inductee and biochemist Florence B. Seibert; Turing Award recipient Ron Rivest; inventors Samuel F.B. Morse and Eli Whitney; Nobel Prize in Chemistry laureate John B. Goodenough; lexicographer Noah Webster; and theologians Jonathan Edwards and Reinhold Niebuhr.

In the sporting arena, Yale alumni include baseball players Ron Darling and Craig Breslow and baseball executives Theo Epstein and George Weiss; football players Calvin Hill, Gary Fenick, Amos Alonzo Stagg, and “the Father of American Football” Walter Camp; ice hockey players Chris Higgins and Olympian Helen Resor; Olympic figure skaters Sarah Hughes and Nathan Chen; nine-time U.S. Squash men’s champion Julian Illingworth; Olympic swimmer Don Schollander; Olympic rowers Josh West and Rusty Wailes; Olympic sailor Stuart McNay; Olympic runner Frank Shorter; and others.

From “Horizon” The EU Research and Innovation Magazine : “The mysterious black behemoths controlling our galaxies”

From “Horizon” The EU Research and Innovation Magazine

2.13.23
Anthony King

The innermost rim of this gas disc is accreting onto a massive black hole. Credit: © Michela Mapelli.

Scientists try to unravel the birth and growth and power of black holes-some of the most forceful yet difficult-to-detect objects in our Universe.

It was only last year that astronomers were finally able to unveil the first pictures of the supermassive black hole at the centre of our Milky Way galaxy. But you couldn’t actually see the black hole itself, not directly. That’s because it is so dense that its gravitational pull prevents even light from escaping.

But the image of SGR A*, as our galaxy’s black hole is known, revealed a glowing halo of gas around the object – an object that we now know has a million times more mass than our Sun.

Recent discoveries like that, as well as many others, have astonished astronomers.

‘Over the last few years, everything we thought we knew about black holes now comes with a question mark,’ said Professor Michela Mapelli, an astrophysicist at the University of Padua in Italy.

Everyone has heard of black holes. Few people, though, realise just how much these weird objects continue to vex astronomers.

One black hole announced itself to astronomers last year when it shredded and then swallowed a star that had wandered too close. Another was described as the fastest-growing black hole ever observed, devouring the equivalent mass of one Earth every second. As a result, it’s already 3 billion times more massive than our Sun.

Cosmic minnows

Mapelli studies stellar black holes, which form when a large, fast-burning star collapses in on itself. Compared to the supermassive ones, these black holes are cosmic minnows.

Astronomers had expected such black holes to possess between five to 10 times the mass of our Sun.

But the truth is that these types of black hole come in a much wider range of sizes. In recent years, some have been discovered that are up to about 100 solar masses, as well as one as small as 2.6.

‘We have discovered features and a mass range of black holes that we could not even imagine before the recent observations,’ Mapelli said.

One system that intrigues her is known as binary black holes – where two orbit one another. This can happen when two stars that orbit each other both end their life as black holes.

Then again, there could be many other ways to form binary black holes and this is something that Mapelli studies in her DEMOBLACK project, funded by the European Research Council.

‘Seven years ago, most people were sceptical about the existence of binary black holes,’ she said. ‘Even theorists were not convinced about their existence.’

Now, Mapelli said, almost 100 of them have been discovered. They spew out gravitational waves, ripples in space-time that can be snagged by sophisticated detectors at the Laser Interferometer Gravitational-Wave Observatory in the US and Italy’s Virgo interferometer.

Caltech/MIT Advanced aLigo at Hanford, WA, Livingston, LA; and VIRGO Gravitational Wave interferometer, near Pisa(IT).

Most astrophysicists, according to Mapelli, doubted that two black holes could get intimate enough to merge, but then gravitational waves began signalling the collision of black holes. One peculiar merger event in 2019 happened between black holes 60 and 80 solar masses.

Whether these black holes formed directly from stars isn’t known. This is because the assumption that stellar-born black holes were between five and 10 solar masses has now been sunk.

‘There is a really big question mark over whether the maximum mass of a stellar black hole is just 60 solar masses, or could it be 90, or even 300?’ said Mapelli. ‘I feel guilty about this large uncertainty because I personally helped cause this situation.’

Galactic monsters

The biggest beasts lie at the centre of almost every galaxy. Nearly all are active, with gravity-sucking hot gas inside them. Some of these black holes have masses up to 10 billion times the mass of our Sun.

‘These are real monsters,’ said Professor Christopher Reynolds at the University of Cambridge in the UK. ‘Their influence in a galaxy can extend 100, even 200, light years out.’

Even at those astronomical distances, stars and galaxies still feel the gravitational tug of these black holes. But their energy blasts as they consume matter can be felt even farther out, as far as 100 000 light years or more.

In the EU-funded DISKtoHALO project, Reynolds is investigating how these supermassive black holes grow, suck hot gas inside them and generate explosions of energy outwards.

‘We know these black holes produce jets of energy, sending shocks outwards,’ he said.

One thing that astrophysicists haven’t been able to figure out yet is why gas in the core of some galaxies can be so hot – up to 10 to 100 million °C – yet the systems are billions of years old and therefore should have had plenty of time to cool down.

How the black holes interact with their immediate surroundings and distant parts of their galaxy is an extremely taxing conundrum. Computer models struggle to help because this requires insight into relatively small scales as well as ginormous scales measured in light years.

‘You are talking about something the size of a tennis ball regulating something that is Earth’s size,’ Reynolds said.

One way to study these supermassive black holes at the centre of galaxy clusters is to examine the hot gases in their vicinity. It is impossible to see these gases with a telescope, but their energy is observable via the X-rays they send out because they are so hot.

Again, it remains unknown why the hot gas doesn’t cool down and coalesce into stars.

‘You need a heater to send out energy in the middle of the cluster and the only heater powerful enough are supermassive black holes,’ Reynolds said.

How precisely this heater works continues to mystify him and his colleagues. It is clear, however, that supermassive black holes do not live tranquilly.

‘These black holes are not even spherical, but they spin themselves into a disc that is rife with instabilities,’ Reynolds said.

Despite new insights into these strange galactic creatures, the true nature of black holes remains obscure. Past assumptions have been shaken.

What we can be sure of is that black holes will continue to puzzle the brightest minds in astronomy.

Research in this article was funded via the EU’s European Research Council (ERC). If you liked this article, please consider sharing it on social media.

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