Dedicated to spreading the Good News of Basic and Applied Science at great research institutions world wide. Good science is a collaborative process. The rule here: Science Never Sleeps.
I am telling the reader this story in the hope of impelling him or her to find their own story and start a wordpress blog. We all have a story. Find yours.
The oldest post I can find for this blog is From FermiLab Today: Tevatron is Done at the End of 2011 (but I am not sure if that is the first post, just the oldest I could find.)
But the origin goes back to 1985, Timothy Ferris Creation of the Universe PBS, November 20, 1985, available in different videos on YouTube; The Atom Smashers, PBS Frontline November 25, 2008, centered at Fermilab, not available on YouTube; and The Big Bang Machine, with Sir Brian Cox of U Manchester and the ATLAS project at the LHC at CERN.
In 1993, our idiot Congress pulled the plug on The Superconducting Super Collider, a particle accelerator complex under construction in the vicinity of Waxahachie, Texas. Its planned ring circumference was 87.1 kilometers (54.1 mi) with an energy of 20 Tev per proton and was set to be the world’s largest and most energetic. It would have greatly surpassed the current record held by the Large Hadron Collider, which has ring circumference 27 km (17 mi) and energy of 13 TeV per proton.
If this project had been built, most probably the Higgs Boson would have been found there, not in Europe, to which the USA had ceded High Energy Physics.
(We have not really left High Energy Physics. Most of the magnets used in The LHC are built in three U.S. DOE labs: Lawrence Berkeley National Laboratory; Fermi National Accelerator Laboratory; and Brookhaven National Laboratory. Also, see below. the LHC based U.S. scientists at Fermilab and Brookhaven Lab.)
I have recently been told that the loss of support in Congress was caused by California pulling out followed by several other states because California wanted the collider built there.
The project’s director was Roy Schwitters, a physicist at the University of Texas at Austin. Dr. Louis Ianniello served as its first Project Director for 15 months. The project was cancelled in 1993 due to budget problems, cited as having no immediate economic value.
Some where I learned that fully 30% of the scientists working at CERN were U.S. citizens. The ATLAS project had 600 people at Brookhaven Lab. The CMS project had 1,000 people at Fermilab. There were many scientists which had “gigs” at both sites.
I started digging around in CERN web sites and found Quantum Diaries, a “blog” from before there were blogs, where different scientists could post articles. I commented on a few and my dismay about the lack of U.S recognition in the press.
Those guys at Quantum Diaries, gave me access to the Greybook, the list of every institution in the world in several tiers processing data for CERN. I collected all of their social media and was off to the races for CERN and other great basic and applied science.
Since then I have expanded the list of sites that I cover from all over the world. I build .html templates for each institution I cover and plop their articles, complete with all attributions and graphics into the template and post it to the blog. I am not a scientist and I am not qualified to write anything or answer scientific questions. The only thing I might add is graphics where the origin graphics are weak. I have a monster graphics library. Any science questions are referred back to the writer who is told to seek his answer from the real scientists in the project.
The blog has to date 900 followers on the blog, its Facebook Fan page and Twitter. I get my material from email lists and RSS feeds. I do not use Facebook or Twitter, which are both loaded with garbage in the physical sciences.
richardmitnick
2:39 pm on January 9, 2023 Permalink
| Reply Tags: "A glimpse into the Very (High Energy) bright future", "VHE": very high energy telescopes, Astrobites ( 409 ), Astronomy ( 10,714 ), Astrophysics ( 8,542 ), Basic Research ( 15,983 ), Cosmology ( 8,658 ), GRB's-Gamma ray bursts, Multi-messenger astronomy is a powerful tool allowing us to study astrophysical sources by looking at different “messengers” from the same source: photons; neutrinos; gravitational waves and cosmi, Multi-messenger Astronomy/Astrophysics, Neutron star mergers ( 4 ), One of the first multi-messenger success stories was a binary neutron star merger observed on August 17th 2017 by the LIGO and Virgo gravitational wave detectors which was named GW170817.
From Astrobites : “A glimpse into the Very (High Energy) bright future”
Authors: Biswajit Banerjee, Gor Oganesyan, Marica Branchesi, Ulyana Dupletsa, Felix Aharonian, Francesco Brighenti, Boris Goncharov, Jan Harms, Michela Mapelli, Samuele Ronchini, and Filippo Santoliquido
Corresponding Author Affiliation: Gran Sasso Science Institute, INFN – Laboratori Nazionali del Gran Sasso, and INAF – Osservatorio Astronomico d’Abruzzo, Italy
Status: ArXiv open access
Multi-messenger astronomy is a powerful tool allowing us to study astrophysical sources by looking at them in different “messengers” – different signals that could come from the same source, which include photons, neutrinos, gravitational waves, and cosmic rays. By studying these different messengers, we can get new insight into the astrophysical sources that produce these signals.
One of the first multi-messenger success stories was a binary neutron star merger observed on August 17th, 2017 by the LIGO and Virgo gravitational wave detectors, which was named GW170817. 1.7 seconds after the merger, the Fermi and INTEGRAL satellites observed a short gamma-ray burst, GRB 170817A, which was associated with the gravitational wave signal.
(For more information about GRBs, check out the Astrobites Guide to Transient Astronomy!) This discovery was hugely exciting in the multi-messenger astronomy community – it cemented neutron star mergers as the source of short gamma-ray bursts (GRBs), and paved the way for further investigation of neutron star mergers in both gravitational waves and light.
Since then, more investigation into short GRBs has taken place, but there are still open questions to solve. Next generation very high energy (VHE) telescopes and next generation gravitational wave detectors may give us more insight into the properties of neutron star mergers, which is the topic of today’s paper.
Promptly searching for prompt emissions
We separate gamma-ray bursts (GRBs) into two types based on the length of time they last, called short (lasting less than 2 seconds) and long (lasting more than 2 seconds). Short GRBs are those associated with binary neutron star mergers, which is the focus of today’s paper.
Figure 1: A schematic of the gravitational waves observed from a binary neutron star merger, and the prompt emission of photons after the merger. The light blue line shows the gravitational wave, which increases rapidly in frequency and amplitude before the merge. After a short delay, the short gamma-ray burst can be seen (dark red color) which is powered by relativistic jets after the merge of the two neutron stars. (Figure 2 in the paper.)
There are often two phases of GRB emission: the prompt or initial burst phase, and an afterglow or later emission. In this paper, the authors target the prompt phase of the emission, which is believed to be powered by relativistic jets, a high energy beam of photons that is produced when the neutron stars merge. By looking at this initial burst of light, astronomers can gain insight into what is happening inside the jet, and what is powering the high energy photons we see.
Although we’ve seen very high energy (energies greater than 30 GeV) emission from the afterglow phase of GRBs before, we have not yet observed VHE emission from the prompt phase. Observing this emission is crucial to our understanding of the relativistic jet which produces the GRB, but observation of the prompt emission has its challenges.
Today’s paper analyses the prospects for detection of VHE gamma-rays from binary neutron star mergers with the next generation of gravitational wave detectors in the Einstein Telescope (ET) and Cosmic Explorer (CE) and the next generation of VHE gamma-ray telescopes using the Cherenkov Telescope Array (CTA).
Two of the main challenges to observing a short GRB from a gravitational wave event are the localizations of the events and the time it takes to reposition the telescope after an event occurs.
Gravitational wave event locations are typically difficult to pinpoint, leading to large localization areas on the sky (often up to 100s or 1000s of square degrees) while most VHE telescopes have much smaller fields of view (10s of degrees). Both the ET and CE gravitational wave detectors are expected to improve the localization of the gravitational wave event, even before the merge happens.
These telescopes will also be able to detect the inspiral-the period right before the merge when the neutron stars get very close together-of the two neutron stars which will give early warning to telescopes up to 15 minutes before the merge happens.
Figure 2: Number of gravitational wave events expected to be detected per year using the next generation of gravitational wave detectors, with an early warning (time before the merger) of 15 minutes (left panel) or 5 minutes (right panel). These are shown versus their sky localization on the x-axis in degrees squared. The θv<10 degrees in the y-axis means that we are positioned to see the relativistic jets from these mergers, which means that we could observe a short GRB from these events. (Figure 5 bottom left two panels in the paper).
Figure 3: Number of CTA VHE prompt photon detections expected from these binary neutron star mergers from Figure 2 (above), assuming either 15 minutes (left) or 5 minutes (right) early warning time. There are more gravitational wave events with a 5 minute early warning time than 15 minutes, leading to more detections, but as the sky localization in either case gets large the field of view of the telescopes can no longer cover the entire region where the gravitational wave event may be. (Figure 7 first column in the paper).
This early warning will be a huge advantage to telescopes trying to observe the burst of light expected from the merge. They will be able to reposition and be ready for the burst before it happens, which is critical since a short GRB lasts only up to 2 seconds.
The Čerenkov Telescope Array (CTA) also brings large improvements to these issues on the VHE photon side. CTA’s Medium Size Telescopes have a field of view of 44 square degrees and 90 second slew time (the slew time is the time it takes to re-point the telescopes), and its Large Size Telescopes have a field of view of 13 square degrees and 20 second slew time. Using this, and the early warning from the gravitational wave detectors, CTA could possibly provide the first detection of this VHE prompt photon emission from a binary neutron star merger.
The authors use a simulation of both the gravitational wave detectors and the CTA medium size telescopes to calculate the number of binary neutron star mergers that CTA could observe VHE photons from the prompt phase of a GRB. With only 5 minutes of early warning from ET and CE, CTA would be able to detect VHE prompt photons from many GRBs, even those with large (more than 1000 square degrees) localizations!
The takeaways
With the next generation of both gravitational wave detectors and VHE gamma-ray detectors, searches for VHE photon emission from binary neutron star mergers will be within reach for the first time. This will allow astronomers and astrophysicists to probe the fundamental properties of relativistic jets formed during the merger of the two neutron stars.
Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.
Why read Astrobites?
Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.
A highly unusual blast of high-energy light from a nearby galaxy has been linked by scientists to a neutron star merger.
The event, detected in December 2021 by NASA’s Neil Gehrels Swift Observatory and the Fermi Gamma-ray Space Telescope, was a gamma-ray burst—an immensely energetic explosion which can last from a few milliseconds to several hours.
This gamma-ray burst, identified as GRB 211211A, lasted about a minute—a relatively lengthy explosion, which would usually signal the collapse of a massive star into a supernova. But this event contained an excess of infrared light and was much fainter and faster-fading than a classical supernova, hinting that something different was going on.
In a new study, published in Nature [below], an international team of scientists showed that the infrared light detected in the burst came from a kilonova. This is a rare event, thought to be generated as neutron stars, or a neutron star and a black hole collide, producing heavy elements such as gold and platinum. Thus far, these events, called kilonovae, have only been associated with gamma-ray bursts with durations of less than two seconds.
The work was led by Jillian Rastinejad at Northwestern University along with physicists from the University of Birmingham (UK) and the University of Leicester (UK), and Radboud University (NL).
Dr. Matt Nicholl, an Associate Professor at the University of Birmingham, modeled the kilonova emission. “We found that this one event produced about 1,000 times the mass of the Earth in very heavy elements. This supports the idea that these kilonovae are the main factories of gold in the universe,” he said.
Although up to 10% of long gamma-ray bursts are suspected to be caused by the merging of neutron star or neutron stars and black holes, no firm evidence—in the form of kilonovae—had previously been identified.
Dr. Gavin Lamb, a post-doctoral researcher at the University of Leicester, explained: “A gamma-ray burst is followed by an afterglow that can last several days. These afterglows behave in a very characteristic manner, and by modeling them we can expose any extra emission components, such as a supernova or a kilonova.”
The kilonova generated by GRB 211211A is the closest to have been discovered without gravitational waves, and has exciting implications for the upcoming gravitational wave observation run, starting in 2023. Its proximity in a neighboring galaxy only 1bn light years away gave scientists the opportunity to study the properties of the merger in unprecedented detail.
A related paper from the same collaboration in Nature Astronomy [below], led by Dr. Benjamin Gompertz, Assistant Professor at the University of Birmingham, describes some of these properties.
In particular, the team identified how the jet of high energy electrons, traveling at almost the speed of light and causing the gamma-ray burst, changed with time. The cooling down of this jet was shown to be responsible for the long lasting GRB emission.
In the paper, the team also described how close observation of GRB 211211A can offer fascinating insights into other previously unexplained gamma-ray bursts which have appeared not to fit with standard interpretations.
Dr. Gompertz said, “This was a remarkable GRB. We don’t expect mergers to last more than about two seconds. Somehow, this one powered a jet for almost a full minute. It’s possible the behavior could be explained by a long-lasting neutron star, but we can’t rule out that what we saw was a neutron star being ripped apart by a black hole.
“Studying more of these events will help us determine which is the right answer and the detailed information we gained from GRB 211211A will be invaluable for this interpretation.”
The University of Birmingham (UK) has been challenging and developing great minds for more than a century. Characterized by a tradition of innovation, research at the University has broken new ground, pushed forward the boundaries of knowledge and made an impact on people’s lives. We continue this tradition today and have ambitions for a future that will embed our work and recognition of the Birmingham name on the international stage.
The University of Birmingham is a public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen’s College, Birmingham (founded in 1825 as the Birmingham School of Medicine and Surgery), and Mason Science College (established in 1875 by Sir Josiah Mason), making it the first English civic or ‘red brick’ university to receive its own royal charter. It is a founding member of both the Russell Group (UK) of British research universities and the international network of research universities, Universitas 21.
The student population includes 23,155 undergraduate and 12,605 postgraduate students, which is the 7th largest in the UK (out of 169). The annual income of the institution for 2019–20 was £737.3 million of which £140.4 million was from research grants and contracts, with an expenditure of £667.4 million.
The university is home to the Barber Institute of Fine Arts, housing works by Van Gogh, Picasso and Monet; the Shakespeare Institute; the Cadbury Research Library, home to the Mingana Collection of Middle Eastern manuscripts; the Lapworth Museum of Geology; and the 100-metre Joseph Chamberlain Memorial Clock Tower, which is a prominent landmark visible from many parts of the city. Academics and alumni of the university include former British Prime Ministers Neville Chamberlain and Stanley Baldwin, the British composer Sir Edward Elgar and eleven Nobel laureates.
Scientific discoveries and inventions
The university has been involved in many scientific breakthroughs and inventions. From 1925 until 1948, Sir Norman Haworth was Professor and Director of the Department of Chemistry. He was appointed Dean of the Faculty of Science and acted as Vice-Principal from 1947 until 1948. His research focused predominantly on carbohydrate chemistry in which he confirmed a number of structures of optically active sugars. By 1928, he had deduced and confirmed the structures of maltose, cellobiose, lactose, gentiobiose, melibiose, gentianose, raffinose, as well as the glucoside ring tautomeric structure of aldose sugars. His research helped to define the basic features of the starch, cellulose, glycogen, inulin and xylan molecules. He also contributed towards solving the problems with bacterial polysaccharides. He was a recipient of the Nobel Prize in Chemistry in 1937.
The cavity magnetron was developed in the Department of Physics by Sir John Randall, Harry Boot and James Sayers. This was vital to the Allied victory in World War II. In 1940, the Frisch–Peierls memorandum, a document which demonstrated that the atomic bomb was more than simply theoretically possible, was written in the Physics Department by Sir Rudolf Peierls and Otto Frisch. The university also hosted early work on gaseous diffusion in the Chemistry department when it was located in the Hills building.
Physicist Sir Mark Oliphant made a proposal for the construction of a proton-synchrotron in 1943, however he made no assertion that the machine would work. In 1945, phase stability was discovered; consequently, the proposal was revived, and construction of a machine that could surpass proton energies of 1 GeV began at the university. However, because of lack of funds, the machine did not start until 1953. The DOE’s Brookhaven National Laboratory (US) managed to beat them; they started their Cosmotron in 1952, and had it entirely working in 1953, before the University of Birmingham.
In 1947, Sir Peter Medawar was appointed Mason Professor of Zoology at the university. His work involved investigating the phenomenon of tolerance and transplantation immunity. He collaborated with Rupert E. Billingham and they did research on problems of pigmentation and skin grafting in cattle. They used skin grafting to differentiate between monozygotic and dizygotic twins in cattle. Taking the earlier research of R. D. Owen into consideration, they concluded that actively acquired tolerance of homografts could be artificially reproduced. For this research, Medawar was elected a Fellow of the Royal Society. He left Birmingham in 1951 and joined the faculty at University College London (UK), where he continued his research on transplantation immunity. He was a recipient of the Nobel Prize in Physiology or Medicine in 1960.
Media Contact:
Claire Andreoli claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md
Gamma-ray burst 211211A, the location of which is circled in red, erupted on the outskirts of a spiral galaxy around 1 billion light-years away in the constellation Boötes. The NASA/ESA Hubble Space Telescope captured the image with its Wide Field Camera 3 and Advanced Camera for Surveys. Credit: NASA, ESA, Rastinejad et al. (2022), and Gladys Kober (Catholic Univ. of America)
On Dec. 11, 2021, NASA’s Neil Gehrels Swift Observatory and Fermi Gamma-ray Space Telescope detected a blast of high-energy light from the outskirts of a galaxy around 1 billion light-years away. The event has rattled scientists’ understanding of gamma-ray bursts (GRBs), the most powerful events in the universe.
For the last few decades, astronomers have generally divided GRBs into two categories. Long bursts emit gamma rays for two seconds or more and originate from the formation of dense objects like black holes in the centers of massive collapsing stars. Short bursts emit gamma rays for less than two seconds and are caused by mergers of dense objects like neutron stars. Scientists sometimes observe short bursts with a following flare of visible and infrared light called a kilonova.
“This burst, named GRB 211211A, was paradigm-shifting as it is the first long-duration gamma-ray burst traced to a neutron star merger origin,” said Jillian Rastinejad, a graduate student at Northwestern University in Evanston, Illinois, who led one team that studied the burst.
“The high-energy burst lasted about a minute, and our follow-up observations led to the identification of a kilonova. This discovery has deep implications for how the universe’s heavy elements came to be.”
NASA’s Fermi, Swift Capture Revolutionary Gamma-Ray Burst.
Watch to learn how an event called GRB 211211A rocked scientists’s understanding of gamma-ray bursts – the most powerful explosions in the cosmos. Credit: NASA’s Goddard Space Flight Center.
A classic short gamma-ray burst begins with two orbiting neutron stars, the crushed remnants of massive stars that exploded as supernovae. As the stars circle ever closer, they strip neutron-rich material from each other. They also generate gravitational waves, or ripples in space-time – although none were detected from this event.
Eventually the neutron stars collide and merge, creating a cloud of hot debris emitting light across multiple wavelengths. Scientists hypothesize that jets of high-speed particles, launched by the merger, produce the initial gamma-ray flare before they collide with the wreckage. Heat generated by the radioactive decay of elements in the neutron-rich debris likely creates the kilonova’s visible and infrared light. This decay results in the production of heavy elements like gold and platinum.
“Many years ago, Neil Gehrels, an astrophysicist and Swift’s namesake, suggested that neutron star mergers could produce some long bursts,” said Eleonora Troja, an astrophysicist at the University of Rome who led another team that studied the burst. “The kilonova we observed is the proof that connects mergers to these long-duration events, forcing us to rethink how black holes are formed.”
Fermi and Swift detected the burst simultaneously, and Swift was able to rapidly identify its location in the constellation Boötes, enabling other facilities to quickly respond with follow-up observations. Their observations have provided the earliest look yet at the first stages of a kilonova.
Many research groups have delved into the observations collected by Swift, Fermi, the Hubble Space Telescope, and others.
Some have suggested the burst’s oddities could be explained by the merger of a neutron star with another massive object, like a black hole. The event was also relatively nearby, by gamma-ray burst standards, which may have allowed telescopes to catch the kilonova’s fainter light. Perhaps some distant long bursts could also produce kilonovae, but we haven’t been able to see them.
Two neutron stars begin to merge in this illustration, blasting a jet of high-speed particles and producing a cloud of debris. Scientists think these kinds of events are factories for a significant portion of the universe’s heavy elements, including gold. Credits: A. Simonnet (Sonoma State Univ.) and NASA’s Goddard Space Flight Center.
The light following the burst, called the afterglow emission, also exhibited unusual features. Fermi detected high-energy gamma rays starting 1.5 hours post-burst and lasting more than 2 hours. These gamma rays reached energies of up to 1 billion electron volts. (Visible light’s energy measures between about 2 and 3 electron volts, for comparison.)
“This is the first time we’ve seen such an excess of high-energy gamma rays in the afterglow of a merger event. Normally that emission decreases over time,” said Alessio Mei, a doctoral candidate at the Gran Sasso Science Institute in L’Aquila, Italy, who led a group that studied the data. “It’s possible these high-energy gamma rays come from collisions between visible light from the kilonova and electrons in particle jets. The jets could be weakening ones from the original explosion or new ones powered by the resulting black hole or magnetar.”
Scientists think neutron star mergers are a major source of the universe’s heavy elements. They based their estimates on the rate of short bursts thought to occur across the cosmos. Now they’ll need to factor long bursts into their calculations as well.
A team led by Benjamin Gompertz, an astrophysicist at the University of Birmingham in the United Kingdom, looked at the entire high-energy light curve, or the evolution of the event’s brightness over time. The scientists noted features that might provide a key for identifying similar incidents – long bursts from mergers – in the future, even ones that are dimmer or more distant. The more astronomers can find, the more they can refine their understanding of this new class of phenomena.
On Dec. 7, 2022, papers led by Rastinejad, Troja, and Mei were published in the scientific journal Nature [below], and a paper led by Gompertz was published in Nature Astronomy [below].
“This result underscores the importance of our missions working together and with others to provide multiwavelength follow up of these kinds of phenomenon,” said Regina Caputo, Swift project scientist, at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Similar coordinated efforts have hinted that some supernovae might produce short bursts, but this event is the final nail in the coffin for the simple dichotomy we’ve used for years. You never know when you might find something surprising.”
NASA’s Goddard Space Flight Center manages the Swift and Fermi missions.
Swift is a collaboration with The Pennsylvania State University, the DOE’s Los Alamos National Laboratory in New Mexico, and Northrop Grumman Space Systems in Dulles, Virginia, with important contributions from partners in the United Kingdom and Italy.
Fermi is a collaboration with the U.S. Department of Energy, with important contributions from partners in France, Germany, Italy, Japan, Sweden, and the United States.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). Goddard manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.
NASA’s Goddard Space Flight Center, Greenbelt, MD is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.
Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.
Goddard is one of four centers built by NASA since its founding on July 29, 1958. It is NASA’s first, and oldest, space center. Its original charter was to perform five major functions on behalf of NASA: technology development and fabrication; planning; scientific research; technical operations; and project management. The center is organized into several directorates, each charged with one of these key functions.
Until May 1, 1959, NASA’s presence in Greenbelt, MD was known as the Beltsville Space Center. It was then renamed the Goddard Space Flight Center (GSFC), after Robert H. Goddard. Its first 157 employees transferred from the United States Navy’s Project Vanguard missile program, but continued their work at the Naval Research Laboratory in Washington, D.C., while the center was under construction.
Goddard Space Flight Center contributed to Project Mercury, America’s first manned space flight program. The Center assumed a lead role for the project in its early days and managed the first 250 employees involved in the effort, who were stationed at Langley Research Center in Hampton, Virginia. However, the size and scope of Project Mercury soon prompted NASA to build a new Manned Spacecraft Center, now the Johnson Space Center, in Houston, Texas. Project Mercury’s personnel and activities were transferred there in 1961.
The Goddard network tracked many early manned and unmanned spacecraft.
Goddard Space Flight Center remained involved in the manned space flight program, providing computer support and radar tracking of flights through a worldwide network of ground stations called the Spacecraft Tracking and Data Acquisition Network (STDN). However, the Center focused primarily on designing unmanned satellites and spacecraft for scientific research missions. Goddard pioneered several fields of spacecraft development, including modular spacecraft design, which reduced costs and made it possible to repair satellites in orbit. Goddard’s Solar Max satellite, launched in 1980, was repaired by astronauts on the Space Shuttle Challenger in 1984. The Hubble Space Telescope, launched in 1990, remains in service and continues to grow in capability thanks to its modular design and multiple servicing missions by the Space Shuttle.
Today, the center remains involved in each of NASA’s key programs. Goddard has developed more instruments for planetary exploration than any other organization, among them scientific instruments sent to every planet in the Solar System. The center’s contribution to the Earth Science Enterprise includes several spacecraft in the Earth Observing System fleet as well as EOSDIS, a science data collection, processing, and distribution system. For the manned space flight program, Goddard develops tools for use by astronauts during extra-vehicular activity, and operates the Lunar Reconnaissance Orbiter, a spacecraft designed to study the Moon in preparation for future manned exploration.
President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.
Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.
Study Finds Long Gamma-ray Bursts Can Be Generated by Neutron Star Mergers.
For nearly two decades, astrophysicists have believed that long gamma-ray bursts (GRBs) resulted solely from the collapse of massive stars. Now, a new study upends that long-established and long-accepted belief.
Led by Northwestern University, a team of astrophysicists have uncovered new evidence that at least some long GRBs also can result from neutron star mergers, which were previously believed to result only from short GRBs.
After detecting a 50-second-long GRB in December 2021, the team began searching for the long GRB’s afterglow, an incredibly luminous and fast-fading burst of light that often precedes a supernova. But, instead, they uncovered evidence of a kilonova, a rare event that only occurs after the merger of a neutron star with another compact object (either another neutron star or a black hole).
The research, which includes data from two Maunakea Observatories [above] in Hawaiʻi, W. M. Keck Observatory and Gemini Observatory, is published in today’s issue of the journal Nature [below].
“This event looks unlike anything else we have seen before from a long gamma-ray burst,” said Jillian Rastinejad, a Northwestern Ph.D. student, who led the study. “Its gamma-rays resemble those of bursts produced by the collapse of massive stars. Given that all other confirmed neutron star mergers we have observed have been accompanied by bursts lasting less than two seconds, we had every reason to expect this 50-second GRB was created by the collapse of a massive star. This event represents an exciting paradigm shift for gamma-ray burst astronomy.”
“When we followed this long gamma-ray burst, we expected it would lead to evidence of a massive star collapse,” said Northwestern’s Wen-fai Fong, a senior author on the study. “Instead, what we found was very different. When I entered the field 15 years ago, it was set in stone that long gamma-ray bursts come from massive star collapses. This unexpected finding not only represents a major shift in our understanding but also excitingly opens up a new window for discovery.”
Fong is an assistant professor of physics and astronomy in Northwestern’s Weinberg College of Arts and Sciences and a key member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). Rastinejad, a Ph.D. student in CIERA and member of Fong’s research group, is the paper’s first author.
The brightest and most energetic explosions since the Big Bang, GRBs are divided into two classes. GRBs with durations less than two seconds are considered short GRBs. If a GRB is longer than two seconds, then it’s considered a long GRB. Researchers previously believed that GRBs on either side of the dividing line must have different origins.
Methodology
NASA’s Neil Gehrels Swift Observatory Burst Alert Telescope and the Fermi Gamma-ray Space Telescope first spotted the bright burst of gamma-ray light, named GRB211211A.
The team then imaged the event at near-infrared wavelengths using Gemini Observatory in Hawaiʻi and the MMT Observatory in Arizona, which revealed an incredibly faint object that quickly faded.
Supernovae don’t fade as quickly and are much brighter, so the team realized it found something unexpected that was previously believed impossible – a kilonova, which can only come from neutron star mergers.
Gamma-ray burst 211211A, the location of which is circled in red, erupted on the outskirts of a spiral galaxy around 1 billion light-years away in the constellation Boötes. The NASA/ESA Hubble Space Telescope captured the image with its Wide Field Camera 3 and Advanced Camera for Surveys. Credit: NASA, ESA
The event wasn’t the only strange part of the study. The GRB’s host galaxy, named SDSS J140910.47+275320.8, is also quite curious. Using Keck Observatory’s DEep Imaging and Multi-Object Spectrograph (DEIMOS) [below], the team was able to trace the GRB’s origins to a galaxy located about 1.1 billion light-years away — making GRB211211A one of the closest GRBs discovered to date.
Furthermore, the Keck Observatory data revealed the host galaxy is young and star-forming, almost exactly opposite of the only other known local universe host of a neutron star merger event: GW170817’s host galaxy NGC4993.
“After the detection of GW170817 and its association with a massive, red-and-dead host galaxy, many astronomers assumed that hosts of neutron star mergers in the near universe would look similar to NGC4993,” said Anya Nugent, a Northwestern graduate student and study co-author. “But this galaxy is fairly young, actively star-forming and not actually that massive. In fact, it looks more similar to short GRB hosts seen deeper in the universe. I think it changes our view of the types of galaxies we should watch when we’re searching for nearby kilonovae.”
What’s Next
In addition to challenging long-established beliefs about how long GRBs are formed, this new discovery also leads to new insights into the mysterious formation of the heaviest elements in the universe, such as platinum and gold. Although researchers have been able to study the astronomical factories that produce lighter elements, such as helium, silicon and carbon, astrophysicists posit that supernova explosions and neutron star mergers produce the heaviest elements. Clear signatures of their creation, however, are rarely observed.
“Kilonovae are powered by the radioactive decay of some of the heaviest elements in the universe,” Rastinejad said. “But kilonovae are very hard to observe and fade very quickly. Now, we know we can also use some long gamma-ray bursts to look for more kilonovae.”
With Webb running, astrophysicists will be able to look for more clues within kilonovae. Because Webb is capable of capturing images and spectra of astronomical objects, it can detect specific elements emitted from the object. Using the Webb, astrophysicists finally might obtain direct observational evidence of heavy elements’ formation.
The DEep Imaging and Multi-Object Spectrograph (DEIMOS) boasts the largest field of view (16.7arcmin by 5 arcmin) of any of the Keck Observatory instruments, and the largest number of pixels (64 Mpix). It is used primarily in its multi-object mode, obtaining simultaneous spectra of up to 130 galaxies or stars. Astronomers study fields of distant galaxies with DEIMOS, efficiently probing the most distant corners of the universe with high sensitivity.
Mission
To advance the frontiers of astronomy and share our discoveries with the world.
The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.
HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.
Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope. LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.
MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.
OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available. Keck OSIRIS on Keck 1.
Keck 2
DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.
NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.
ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.
KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.
ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.
LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.
NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.
Keck NIRC2 Camera on Keck 2.
ABOUT NIRES
The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.
KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.
KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.
International Gemini Observatory probes aftermath of gamma-ray burst and uncovers surprising evidence of colliding neutron stars
While studying the aftermath of a long gamma-ray burst (GRB), two independent teams of astronomers using a host of telescopes in space and on Earth, including the Gemini North telescope on Hawai‘i [below] and the Gemini South telescope in Chile [below], have uncovered the unexpected hallmarks of a kilonova, the colossal explosion triggered by colliding neutron stars. This discovery challenges the prevailing theory that long GRBs exclusively come from supernovae, the end-of-life explosions of massive stars.
Gamma-ray bursts (GRBs) — the most energetic explosions in the Universe — come in two varieties, long and short. Long GRBs, which last a couple of seconds to one minute, form when a star at least 10 times the mass of our Sun explodes as a supernova. Short GRBs, which last less than two seconds, occur when two compact objects, like two neutron stars or a neutron star and a black hole, collide to form a kilonova.
While observing the aftermath of a long GRB detected in 2021, two independent teams of astronomers found the surprising signs of a neutron-star merger rather than the expected signal of a supernova. This surprising result marks the first time that a kilonova has been associated with a long GRB and challenges our understanding of these phenomenally powerful explosions.
The first team to announce this discovery was led by Jillian Rastinejad, a PhD student at Northwestern University. Rastinejad and her colleagues made this startling discovery with the help of Gemini North, part of the International Gemini Observatory, which is operated by NSF’s NOIRLab. The Gemini North observations revealed a telltale near-infrared afterglow at the precise location of the GRB, providing the first compelling evidence of a kilonova associated with this event [1]. Rastinejad’s team promptly reported their Gemini detection in a Gamma-ray Coordinates Network (GCN) Circular.
Astronomers around the world were first alerted to this burst, named GRB 211211A, when a powerful flash of gamma rays was picked up by NASA’s Neil Gehrels Swift Observatory and Fermi Gamma-ray Space Telescope. Initial observations revealed that the GRB was uncommonly nearby, a mere one billion light-years from Earth.
Most GRBs originate in the distant, early Universe. Typically, these objects are so ancient and far flung that their light would have had to travel for more than six billion years to reach Earth. Light from the most-distant GRB ever recorded traveled for nearly 13 billion years before being detected here on Earth [2]. The relative proximity of this newly discovered GRB enabled astronomers to make remarkably detailed follow-up studies with a variety of ground- and space-based telescopes.
“Astronomers usually investigate short GRBs when hunting for kilonovae,” said Rastinejad. “We were drawn to this longer-duration burst because it was so close that we could study it in detail. Its gamma rays also resembled those of a previous, mysterious supernova-less long GRB.”
A unique observational signature of kilonovae is their brightness at near-infrared wavelengths compared to their brightness in visible light. This difference in brightness is due to the heavy elements ejected by the kilonova, which effectively block visible light but allow the longer-wavelength infrared light to pass unimpeded. Observing in the near-infrared, however, is technically challenging and only a handful of telescopes on Earth, like the twin Gemini telescopes, are sensitive enough to detect this kilonova at these wavelengths.
“Thanks to its sensitivity and our rapid-response, Gemini was the first to detect this kilonova in the near-infrared, convincing us that we were observing a neutron-star merger,” said Rastinejad. “Gemini’s nimble capabilities and variety of instruments let us tailor each night’s observing plan based on the previous night’s results, allowing us to make the most of every minute that our target was observable.”
Another team, led by Eleonora Troja, an astronomer at the University of Rome Tor Vergata, independently studied the afterglow using a different and a different series of observations, including the Gemini South telescope in Chile, [3] and independently concluded that the long GRB came from a kilonova.
”We were able to observe this event only because it was so close to us,” said Troja. “It is very rare that we observe such powerful explosions in our cosmic backyard, and every time we do we learn about the most extreme objects in the Universe.”
The fact that two different teams of scientists working with independent datasets both arrived at the same conclusion about the kilonova nature of this GRB provides confidence in this interpretation.
“The kilonova interpretation was so far off from everything we knew about long GRBs that we could not believe our own eyes and spent months testing all the other possibilities,” said Troja. “It is only after ruling out everything else that we realized our decade-long paradigm had to be revised.”
As well as contributing to our understanding of kilonovae and GRBs, this discovery provides astronomers with a new way to study the formation of gold and other heavy elements in the Universe. The extreme physical conditions in kilonovae produce heavy elements such as gold, platinum, and thorium. Astronomers can now identify the sites that are creating heavy elements by searching for the signature of a kilonova following a long-duration gamma-ray burst.
“This discovery is a clear reminder that the Universe is never fully figured out,” said Rastinejad. “Astronomers often take it for granted that the origins of GRBs can be identified by how long the GRBs are, but this discovery shows us there’s still much more to understand about these amazing events.”
“NSF congratulates the science teams for this new and exciting discovery, opening a new window onto cosmic evolution,” said National Science Foundation Director Sethuraman Panchanathan. “The International Gemini Observatory continues to deliver powerful and nimble resources open to the whole scientific community through innovation and partnership.”
The International Gemini Observatory is operated by a partnership of six countries, including the United States through the National Science Foundation, Canada through the National Research Council of Canada, Chile through the Agencia Nacional de Investigación y Desarrollo, Brazil through the Ministério da Ciência, Tecnologia e Inovações, Argentina through the Ministerio de Ciencia, Tecnología e Innovación, and Korea through the Korea Astronomy and Space Science Institute. These Participants and the University of Hawaii, which has regular access to Gemini, each maintain a National Gemini Office to support their local users.
Notes
[1] Rastinejad and her colleagues made initial follow-up observations of the burst using the Nordic Optical Telescope.
Following the critical Gemini North observations, they continued their observations of the fading kilonova with the Karl G. Jansky Very Large Array, the Calar Alto Observatory, and the MMT Observatory, and obtained later observations with the Large Binocular Telescope, the W. M. Keck Observatory, the Gran Telescopio Canarias, and the NASA/ESA Hubble Space Telescope.
[2] Light that has traveled nearly 13 billion years to reach Earth would have a redshift (z) of about 7. Due to the accelerating expansion of the Universe, that would roughly equate to a distance of 24.5 billion light-years today. When talking about large redshifts, those greater than 1, and cosmically distant objects, it is more accurate to state how many billions of years the light has traveled rather than a distance in light-years.
[3] Troja and her colleagues initially observed the afterglow of this event with the Devasthal Optical Telescope, the Multicolor Imaging Telescopes for Survey and Monstrous Explosions, and the Calar Alto Observatory. They obtained observations of the host galaxy with the NASA/ESA Hubble Space Telescope.
Rastinejad, J., Gompertz, B., Levan, A., & Fong, W., et al. (2022). “A kilonova following a long-duration gamma-ray burst at 350 Mpc.” Published in the journal Nature [below].
Troja, E., Fryer, C.L., O’Connor, B., & Ryan, G., et al. (2022). “A nearby long gamma-ray burst from a merger of compact objects.” Published in the journal Nature [below].
Science papers: Nature Nature
See the science papers for instructive material with images.
Gemini’s mission is to advance our knowledge of the Universe by providing the international Gemini Community with forefront access to the entire sky.
The NSF NOIRLab Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located on Mauna Kea, Hawai’i (Gemini North) and the other telescope, Gemini South, on Cerro Pachón in central Chile); together the twin telescopes provide full coverage over both hemispheres of the sky. The telescopes incorporate technologies that allow large, relatively thin mirrors, under active control, to collect and focus both visible and infrared radiation from space.
The Gemini Observatory provides the astronomical communities in six partner countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country’s contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the National Science Foundation, the Canadian National Research Council, the Chilean Comisión Nacional de Investigación Cientifica y Tecnológica, the Australian Research Council, the Argentinean Ministerio de Ciencia, Tecnología e Innovación Productiva, and the Brazilian Ministério da Ciência, Tecnologia e Inovação. The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.
It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with National Science Foundation and is headquartered in Tucson, Arizona.
The astronomical community is honored to have the opportunity to conduct astronomical research on Iolkam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawaiʻi, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence that these sites have to the Tohono O’odham Nation, to the Native Hawaiian community, and to the local communities in Chile, respectively.
Artist’s concept of the mighty blast from a gamma-ray burst. Researchers in Italy and the UK have found one whose burst was so powerful, it has traveled to us from the infant universe. Image via NASA/ Swift/ Mary Pat Hrybyk-Keith/ John Jones.
Gamma-ray bursts are the most powerful explosions in the universe. We can’t see them with the eye alone, but if we could, we might see them popping off every now and then in our night sky. And they’re not nearby. Most originate in distant galaxies. Yet, they release such incredible amounts of light and energy that they can be seen far across vast distances. In September 2022, an international team of researchers said they’ve detected a gamma ray burst that left its source when the universe was in its infancy, at only 880 million years old.
The scientists, led by Andrea Rossi at the Italian National Institute of Astrophysics (INAF), published their peer-reviewed paper in Astronomy & Astrophysics [below] on September 21, 2022.
Giant gamma-ray burst reaches Earth
The researchers first detected the light from the gamma-ray burst – named GRB 210905A – on September 5, 2021. The light from the explosion reached our planet after traveling for more than 12.8 billion years. That’s a long trip! It is one of the most distant GRBs ever detected so far. The afterglow light from the burst is also one of the most luminous ever seen. The burst itself must have been massive to produce that much light and energy. Instruments onboard the Neil Gehrels Swift Observatory and Konus first detected the burst. NGSO orbits Earth, while Konus is a GRB monitor on the Wind spacecraft in interplanetary space. It is specifically designed to search for GRBs.
“Once again, we have shown that when dealing with transient phenomena, you need to be able to act quickly and have the right tools. You have to be able to both observe the phenomenon when it is still bright to obtain a clear and unequivocal result, and then you need access to those facilities that allow you to cover a large wavelength range, from gamma-rays to X-rays, optical and radio.”
Similar to other GRBs
This burst may have been one of the most distant ever recorded, but the researchers say that its characteristics are similar to ones much closer to Earth. For example, the X-ray wavelength properties of the explosion are remarkably similar to those from GRB explosions happening closer to us. This shows that whatever causes the explosion, it hasn’t changed much, if at all, during the lifetime of the universe. Rossi said:
“Thanks to our observations, we can conclude that the mechanism responsible for GRBs does not evolve with the universe.”
Only a few GRBs have been seen before from so early in the universe. Team member Carole Mundell said:
“As one of the most powerful and distant cosmic explosions yet found, this rare gamma-ray burst joins a tiny club of such bursts discovered from early in the history of the universe, and this one is from the brightest host galaxy ever detected. This discovery gives us new understanding and confirmation that massive stars – which live fast and die hard – are forming and evolving early in the universe.”
It came from a black hole
So what kind of GRB was this? There are two basic types, long and short. Long GRBs originate from black holes formed after a massive star collapses. Short GRBs are different. They are caused by collisions of dense, compact objects like neutron stars or magnetars. In this case, the GRB is a long one. It is most likely to have originated from a black hole, as the paper stated:
“The total jet energy is likely too large to be sustained by a standard magnetar, and it suggests that the central engine of this burst was a newly formed black hole.”
The researchers say that GRB 210905A is a long type GRB that originated from a black hole. This image is a simulation of a supermassive black hole showing how it distorts the starry background and captures light, producing a black hole silhouette. Image via NASA’s Goddard Space Flight Center/ ESA/ Gaia/ DPAC.
What is a gamma-ray burst?
Gamma-ray bursts are the most powerful singular events in the universe. If your eyes could see them, they would look like brilliant bursts of light. Military satellites accidentally discovered them in the early 1970s. How? Nuclear bomb tests show as gamma-ray flashes to those satellites. These particular flashes, however, did not come from nuclear bombs … They came from deep space!
Eventually, astronomers determined they originated from distant galaxies. The amount of energy in a gamma-ray burst is equivalent to converting all the mass in the sun to pure radiation in a matter of seconds. Now that is powerful!
This newest discovery will help astronomers better understand GRBs and how they behave.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.
richardmitnick
10:03 am on August 3, 2022 Permalink
| Reply Tags: "Out With a Bang:: Explosive Neutron Star Merger Captured for the First Time in Millimeter Light", Astrophysics ( 8,542 ), Basic Research ( 15,983 ), Cosmology ( 8,658 ), Each wavelength added a new dimension to scientists’ understanding of the GRB and millimeter in particular was critical to uncovering the truth about the burst., GRB 211106A belongs to a GRB sub-class known as short-duration gamma-ray bursts., GRB's-Gamma ray bursts, Ground based Millimeter/submillimeter astronomy ( 58 ), Only half-a-dozen short-duration GRBs have been detected at radio wavelengths., The ALMA Observatory (CL), The Atacama Large Millimeter/submillimeter Array (ALMA) has for the first time recorded millimeter-wavelength light from a fiery explosion caused by the merger of a neutron star with another star., The resulting explosion is accompanied by jets moving at close to the speed of light., The study of short-duration GRBs requires the rapid coordination of telescopes around the world and in space operating at all wavelengths., There is plenty of work still to be done across multiple wavelengths both with new GRBs and with GRB 211106A which could uncover additional surprises about these bursts., These explosions-which scientists believe are responsible for the creation of the heaviest elements in the Universe such as platinum and gold-result from the catastrophic merger of binary star systems, These mergers occur because of gravitational wave radiation that removes energy from the orbit of the binary stars causing the stars to spiral in toward each other and merge., When one of these jets is pointed at Earth we observe a short pulse of gamma-ray radiation or a short-duration GRB.
From The ALMA Observatory (CL): “Out With a Bang:: Explosive Neutron Star Merger Captured for the First Time in Millimeter Light”
In the first-ever time-lapse movie of a short-duration gamma-ray burst in millimeter-wavelength light, we see GRB 21106A as captured with the Atacama Large Millimeter/submillimeter Array (ALMA). The millimeter light seen here pinpoints the location of the event to a distant host galaxy in images captured using the Hubble Space Telescope. The evolution of the millimeter light’s brightness provides information on the energy and geometry of the jets produced in the explosion. Credit: T. Laskar (Utah)/ ALMA(ESO/NAOJ/NRAO); S. Dagnello (NRAO/AUI/NSF)
In a first for radio astronomy, scientists have detected millimeter-wavelength light from a short-duration gamma-ray burst. This artist’s conception shows the merger between a neutron star and another star (seen as a disk, lower left) which caused an explosion resulting in the short-duration gamma-ray burst, GRB 211106A (white jet, middle), and left behind what scientists now know to be one of the most luminous afterglows on record (semi-spherical shock wave mid-right). While dust in the host galaxy obscured most of the visible light (shown as colors), millimeter light from the event (depicted in green) was able to escape and reach the Atacama Large Millimeter/submillimeter Array (ALMA), giving scientists an unprecedented view of this cosmic explosion. From the study, the team confirmed that GRB 211106A is one of the most energetic short-duration GRBs ever observed. Credit: ALMA (ESO/NAOJ/NRAO), M. Weiss (NRAO/AUI/NSF)
Scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) have for the first time recorded millimeter-wavelength light from a fiery explosion caused by the merger of a neutron star with another star. The team also confirmed this flash of light to be one of the most energetic short-duration gamma-ray bursts ever observed, leaving behind one of the most luminous afterglows on record. The results of the research will be published in an upcoming edition of The Astrophysical Journal Letters [below].
Gamma-ray bursts (GRBs) are the brightest and most energetic explosions in the Universe, capable of emitting more energy in a matter of seconds than our Sun will emit during its entire lifetime. GRB 211106A belongs to a GRB sub-class known as short-duration gamma-ray bursts. These explosions— which scientists believe are responsible for the creation of the heaviest elements in the Universe, such as platinum and gold— result from the catastrophic merger of binary star systems containing a neutron star. “These mergers occur because of gravitational wave radiation that removes energy from the orbit of the binary stars, causing the stars to spiral in toward each other,” said Tanmoy Laskar, who will soon commence work as an Assistant Professor of Physics and Astronomy at the University of Utah. “The resulting explosion is accompanied by jets moving at close to the speed of light. When one of these jets is pointed at Earth we observe a short pulse of gamma-ray radiation or a short-duration GRB.”
A short-duration GRB usually lasts only a few tenths of a second. Scientists then look for an afterglow, an emission of light caused by the interaction of the jets with surrounding gas. Even still, they’re difficult to detect; only half-a-dozen short-duration GRBs have been detected at radio wavelengths, and until now none had been detected in millimeter wavelengths. Laskar, who led the research while an Excellence Fellow at Radboud University in The Netherlands, said that the difficulty is the immense distance to GRBs, and the technological capabilities of telescopes. “Short-duration GRB afterglows are very luminous and energetic. But these explosions take place in distant galaxies which means the light from them can be quite faint for our telescopes on Earth. Before ALMA, millimeter telescopes were not sensitive enough to detect these afterglows.”
At roughly 20 billion light-years from Earth, GRB 211106A is no exception. The light from this short-duration gamma-ray burst was so faint that while early X-ray observations with NASA’s Neil Gehrels Swift Observatory saw the explosion, the host galaxy was undetectable at that wavelength, and scientists weren’t able to determine exactly where the explosion was coming from.
“Afterglow light is essential for figuring out which galaxy a burst comes from and for learning more about the burst itself. Initially, when only the X-ray counterpart had been discovered, astronomers thought that this burst might be coming from a nearby galaxy,” said Laskar, adding that a significant amount of dust in the area also obscured the object from detection in optical observations with the Hubble Space Telescope.
Each wavelength added a new dimension to scientists’ understanding of the GRB and millimeter in particular was critical to uncovering the truth about the burst. “The Hubble observations revealed an unchanging field of galaxies. ALMA’s unparalleled sensitivity allowed us to pinpoint the location of the GRB in that field with more precision, and it turned out to be in another faint galaxy, which is further away. That, in turn, means that this short-duration gamma-ray burst is even more powerful than we first thought, making it one of the most luminous and energetic on record,” said Laskar.
Wen-fai Fong, an Assistant Professor of Physics and Astronomy at Northwestern University added, “This short gamma-ray burst was the first time we tried to observe such an event with ALMA. Afterglows for short bursts are very difficult to come by, so it was spectacular to catch this event shining so bright. After many years of observing these bursts, this surprising discovery opens up a new area of study, as it motivates us to observe many more of these with ALMA, and other telescope arrays, in the future.”
Joe Pesce, National Science Foundation Program Officer for NRAO/ALMA said, “These observations are fantastic on many levels. They provide more information to help us understand the enigmatic gamma-ray bursts (and neutron-star astrophysics in general), and they demonstrate how important and complementary multi-wavelength observations with space- and ground-based telescopes are in understanding astrophysical phenomena.”
And there is plenty of work still to be done across multiple wavelengths both with new GRBs and with GRB 211106A which could uncover additional surprises about these bursts. “The study of short-duration GRBs requires the rapid coordination of telescopes around the world and in space operating at all wavelengths,” said Edo Berger, Professor of Astronomy at Harvard University. “In the case of GRB 211106A, we used some of the most powerful telescopes available— ALMA, the National Science Foundation’s Karl G. Jansky Very Large Array (VLA), NASA’s Chandra X-ray Observatory, and the Hubble Space Telescope. With the now-operational James Webb Space Telescope (JWST), and future 20-40 meter optical and radio telescopes such as the next generation VLA (ngVLA) we will be able to produce a complete picture of these cataclysmic events and study them at unprecedented distances.”
Not included but definitely important to this area of study is The Square Millimeter Array.
______________________________________________ The Square Kilometre Array (SKA)– a next-generation telescope due to be completed by the end of the decade – will likely be able to make images of the earliest light in the Universe, but for current telescopes the challenge is to detect the cosmological signal of the stars through the thick hydrogen clouds.
Laskar added, “With JWST, we can now take a spectrum of the host galaxy and easily know the distance, and in the future, we could also use JWST to capture infrared afterglows and study their chemical composition. With ngVLA, we will be able to study the geometric structure of the afterglows and the star-forming fuel found in their host environments in unprecedented detail. I am excited about these upcoming discoveries in our field.”
The antennas can be moved across the desert plateau over distances from 150 m to 16 km, which will give ALMA a powerful variable “zoom”, similar in its concept to that employed at the centimetre-wavelength Very Large Array (VLA) site in New Mexico, United States.
The high sensitivity is mainly achieved through the large numbers of antenna dishes that will make up the array.
The telescopes were provided by the European, North American and East Asian partners of ALMA. The American and European partners each provided twenty-five 12-meter diameter antennas, that compose the main array. The participating East Asian countries are contributing 16 antennas (four 12-meter diameter and twelve 7-meter diameter antennas) in the form of the Atacama Compact Array (ACA), which is part of the enhanced ALMA.
By using smaller antennas than the main ALMA array, larger fields of view can be imaged at a given frequency using ACA. Placing the antennas closer together enables the imaging of sources of larger angular extent. The ACA works together with the main array in order to enhance the latter’s wide-field imaging capability.
ALMA has its conceptual roots in three astronomical projects — the Millimeter Array (MMA) of the United States, the Large Southern Array (LSA) of Europe, and the Large Millimeter Array (LMA) of Japan.
The first step toward the creation of what would become ALMA came in 1997, when the National Radio Astronomy Observatory (NRAO) and the European Southern Observatory (ESO) agreed to pursue a common project that merged the MMA and LSA. The merged array combined the sensitivity of the LSA with the frequency coverage and superior site of the MMA. ESO and NRAO worked together in technical, science, and management groups to define and organize a joint project between the two observatories with participation by Canada and Spain (the latter became a member of ESO later).
A series of resolutions and agreements led to the choice of “Atacama Large Millimeter Array”, or ALMA, as the name of the new array in March 1999 and the signing of the ALMA Agreement on 25 February 2003, between the North American and European parties. (“Alma” means “soul” in Spanish and “learned” or “knowledgeable” in Arabic.) Following mutual discussions over several years, the ALMA Project received a proposal from the National Astronomical Observatory of Japan (NAOJ) whereby Japan would provide the ACA (Atacama Compact Array) and three additional receiver bands for the large array, to form Enhanced ALMA. Further discussions between ALMA and NAOJ led to the signing of a high-level agreement on 14 September 2004 that makes Japan an official participant in Enhanced ALMA, to be known as the Atacama Large Millimeter/submillimeter Array. A groundbreaking ceremony was held on November 6, 2003 and the ALMA logo was unveiled.
During an early stage of the planning of ALMA, it was decided to employ ALMA antennas designed and constructed by known companies in North America, Europe, and Japan, rather than using one single design. This was mainly for political reasons. Although very different approaches have been chosen by the providers, each of the antenna designs appears to be able to meet ALMA’s stringent requirements. The components designed and manufactured across Europe were transported by specialist aerospace and astrospace logistics company Route To Space Alliance, 26 in total which were delivered to Antwerp for onward shipment to Chile.
richardmitnick
10:36 am on July 26, 2022 Permalink
| Reply Tags: "Hawaiʻi Telescopes Help Uncover Origins of Castaway Gamma-Ray Bursts", GRB's-Gamma ray bursts, Ground based Optical/Infrared Astronomy ( 15 ), Mauna Kea Observatories Aid in Revealing That Seemingly Lonely Bursts Came From Previously Undiscovered Galaxies in the Early Universe., The gamma-ray burst identified as GRB 151229A, The W.M. Keck Observatory ( 9 )
Mauna Kea Observatories Aid in Revealing That Seemingly Lonely Bursts Came From Previously Undiscovered Galaxies in the Early Universe.
Artist’s impression of a merger of two neutron stars, which produces the remarkably brief (1 to 2 second) yet intensely powerful event known as a short gamma-ray burst. Credit: J. da Silva/Spaceengine/NOIRLab/NSF/AURA.
A number of mysterious gamma-ray bursts appear as lonely flashes of intense energy far from any obvious galactic home, raising questions about their true origins and distances. Using data from some of the most powerful telescopes on Earth and in space, including W. M. Keck Observatory and Gemini North on Mauna Kea, Hawaiʻi, astronomers may have finally found their true origins — a population of distant galaxies, some nearly 10 billion light-years away.
An international team of astronomers has found that certain short gamma-ray bursts (GRBs) did not originate as castaways in the vastness of intergalactic space as they initially appeared. A deeper multi-observatory study instead found that these seemingly isolated GRBs actually occurred in remarkably distant – and therefore faint – galaxies up to 10 billion light-years away.
This discovery suggests that short GRBs, which form during the collisions of neutron stars, may have been more common in the past than expected. Since neutron-star mergers forge heavy elements, including gold and platinum, the universe may have been seeded with precious metals earlier than expected as well.
The study has been accepted for publication in the MNRAS [below].
“Many short GRBs are found in bright galaxies relatively close to us, but some of them appear to have no corresponding galactic home,” said Brendan O’Connor, lead author of the study and an astronomer at both the University of Maryland and the George Washington University. “By pinpointing where the short GRBs originate, we were able to comb through troves of data from multiple observatories to find the faint glow of galaxies that were simply too distant to be recognized before.”
Methodology
This cosmic sleuthing required the combined power of some of the most powerful telescopes on Earth and in space, including two Mauna Kea Observatories in Hawaiʻi – W. M. Keck Observatory and Gemini North telescope [above] – as well as the Gemini South telescope in Chile.
The two Gemini telescopes comprise the International Gemini Observatory, operated by NSF’s NOIRLab. Other observatories involved in this research include the NASA/ESA Hubble Space Telescope, Lowell Discovery Telescope in Arizona, Gran Telescopio Canarias in Spain, and the European Southern Observatory’s Very Large Telescope in Chile.
This image captured by the Gemini North telescope on Mauna Kea in Hawaiʻi reveals the previously unrecognized galactic home of the gamma-ray burst identified as GRB 151229A. Astronomers calculate that this burst, which lies in the direction of the constellation Capricornus, occurred approximately 9 billion years ago. Credit: International Gemini Observatory/NOIRLab/NSF/AURA.
The researchers began their quest by reviewing data on 120 GRBs captured by two instruments aboard NASA’s Neil Gehrels Swift Observatory: Swift’s Burst Alert Telescope, which signaled a burst had been detected; and Swift’s X-ray Telescope, which identified the general location of the GRB’s X-ray afterglow.
Additional afterglow studies made with the Lowell Observatory more accurately pinpointed the location of the GRBs.
The afterglow studies found that 43 of the short GRBs were not associated with any known galaxy and appeared in the comparatively empty space between galaxies.
“These hostless GRBs presented an intriguing mystery and astronomers had proposed two explanations for their seemingly isolated existence,” said O’Connor.
One hypothesis was that the progenitor neutron stars formed as a binary pair inside a distant galaxy, drifted together into intergalactic space, and eventually merged billions of years later. The other hypothesis was that the neutron stars merged many billions of light-years away in their home galaxies, which now appear extremely faint due to their vast distance from Earth.
“We felt this second scenario was the most plausible to explain a large fraction of hostless events,” said O’Connor. “We then used the most powerful telescopes on Earth to collect deep images of the GRB locations and uncovered otherwise invisible galaxies 8 to 10 billion light-years away from Earth.”
To make these detections, the astronomers utilized a variety of optical and infrared instruments, including Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS) [below] and Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) [below], as well as the Gemini Multi-Object Spectrograph mounted on both Gemini North and Gemini South.
This result could help astronomers better understand the chemical evolution of the universe. Merging neutron stars trigger a cascading series of nuclear reactions that are necessary to produce heavy metals, like gold, platinum, and thorium. Pushing back the cosmic timescale on neutron-star mergers means that the young universe was far richer in heavy elements than previously known.
“This pushes the timescale back on when the universe received the ‘Midas touch’ and became seeded with the heaviest elements on the periodic table,” said O’Connor.
ABOUT LRIS
The Low Resolution Imaging Spectrometer (LRIS) is a very versatile and ultra-sensitive visible-wavelength imager and spectrograph built at the California Institute of Technology by a team led by Prof. Bev Oke and Prof. Judy Cohen and commissioned in 1993. Since then, it has seen two major upgrades to further enhance its capabilities: the addition of a second, blue arm optimized for shorter wavelengths of light and the installation of detectors that are much more sensitive at the longest (red) wavelengths. Each arm is optimized for the wavelengths it covers. This large range of wavelength coverage, combined with the instrument’s high sensitivity, allows the study of everything from comets (which have interesting features in the ultraviolet part of the spectrum), to the blue light from star formation, to the red light of very distant objects. LRIS also records the spectra of up to 50 objects simultaneously, especially useful for studies of clusters of galaxies in the most distant reaches, and earliest times, of the universe. LRIS was used in observing distant supernovae by astronomers who received the Nobel Prize in Physics in 2011 for research determining that the universe was speeding up in its expansion.
ABOUT MOSFIRE
The Multi-Object Spectrograph for Infrared Exploration (MOSFIRE), gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this large, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only two billion years after the Big Bang. MOSFIRE was made possible by funding provided by the National Science Foundation.
Mission
To advance the frontiers of astronomy and share our discoveries with the world.
The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.
HIRES – The largest and most mechanically complex of the Keck’s main instruments, the High Resolution Echelle Spectrometer breaks up incoming starlight into its component colors to measure the precise intensity of each of thousands of color channels. Its spectral capabilities have resulted in many breakthrough discoveries, such as the detection of planets outside our solar system and direct evidence for a model of the Big Bang theory.
Keck High-Resolution Echelle Spectrometer (HIRES), at the Keck I telescope. LRIS – The Low Resolution Imaging Spectrograph is a faint-light instrument capable of taking spectra and images of the most distant known objects in the universe. The instrument is equipped with a red arm and a blue arm to explore stellar populations of distant galaxies, active galactic nuclei, galactic clusters, and quasars.
MOSFIRE – The Multi-Object Spectrograph for Infrared Exploration gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this huge, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only 2 billion years after the Big Bang.
OSIRIS – The OH-Suppressing Infrared Imaging Spectrograph is a near-infrared spectrograph for use with the Keck I adaptive optics system. OSIRIS takes spectra in a small field of view to provide a series of images at different wavelengths. The instrument allows astronomers to ignore wavelengths where the Earth’s atmosphere shines brightly due to emission from OH (hydroxl) molecules, thus allowing the detection of objects 10 times fainter than previously available. Keck OSIRIS on Keck 1.
Keck 2
DEIMOS – The Deep Extragalactic Imaging Multi-Object Spectrograph is the most advanced optical spectrograph in the world, capable of gathering spectra from 130 galaxies or more in a single exposure. In ‘Mega Mask’ mode, DEIMOS can take spectra of more than 1,200 objects at once, using a special narrow-band filter.
NIRSPEC – The Near Infrared Spectrometer studies very high redshift radio galaxies, the motions and types of stars located near the Galactic Center, the nature of brown dwarfs, the nuclear regions of dusty starburst galaxies, active galactic nuclei, interstellar chemistry, stellar physics, and solar-system science.
ESI – The Echellette Spectrograph and Imager captures high-resolution spectra of very faint galaxies and quasars ranging from the blue to the infrared in a single exposure. It is a multimode instrument that allows users to switch among three modes during a night. It has produced some of the best non-AO images at the Observatory.
KCWI – The Keck Cosmic Web Imager is designed to provide visible band, integral field spectroscopy with moderate to high spectral resolution, various fields of view and image resolution formats and excellent sky-subtraction. The astronomical seeing and large aperture of the telescope enables studies of the connection between galaxies and the gas in their dark matter halos, stellar relics, star clusters and lensed galaxies.
ADAPTIVE OPTICS – Adaptive optics senses and compensates for the atmospheric distortions of incoming starlight up to 1,000 times per second. This results in an improvement in image quality on fairly bright astronomical targets by a factor 10 to 20.
LASER GUIDE STAR ADAPTIVE OPTICS [pictured above] – The Keck Laser Guide Star expands the range of available targets for study with both the Keck I and Keck II adaptive optics systems. They use sodium lasers to excite sodium atoms that naturally exist in the atmosphere 90 km (55 miles) above the Earth’s surface. The laser creates an “artificial star” that allows the Keck adaptive optics system to observe 70-80 percent of the targets in the sky, compared to the 1 percent accessible without the laser.
NIRC-2/AO – The second generation Near Infrared Camera works with the Keck Adaptive Optics system to produce the highest-resolution ground-based images and spectroscopy in the 1-5 micron range. Typical programs include mapping surface features on solar system bodies, searching for planets around other stars, and analyzing the morphology of remote galaxies.
Keck NIRC2 Camera on Keck 2.
ABOUT NIRES
The Near Infrared Echellette Spectrograph (NIRES) is a prism cross-dispersed near-infrared spectrograph built at the California Institute of Technology by a team led by Chief Instrument Scientist Keith Matthews and Prof. Tom Soifer. Commissioned in 2018, NIRES covers a large wavelength range at moderate spectral resolution for use on the Keck II telescope and observes extremely faint red objects found with the Spitzer and WISE infrared space telescopes, as well as brown dwarfs, high-redshift galaxies, and quasars.
KCRM – The Keck Cosmic Reionization Mapper will complete the Keck Cosmic Web Imager (KCWI), the world’s most capable spectroscopic imager. The design for KCWI includes two separate channels to detect light in the blue and the red portions of the visible wavelength spectrum. KCWI-Blue was commissioned and started routine science observations in September 2017. The red channel of KCWI is KCRM; a powerful addition that will open a window for new discoveries at high redshifts.
KPF – The Keck Planet Finder (KPF) will be the most advanced spectrometer of its kind in the world. The instrument is a fiber-fed high-resolution, two-channel cross-dispersed echelle spectrometer for the visible wavelengths and is designed for the Keck II telescope. KPF allows precise measurements of the mass-density relationship in Earth-like exoplanets, which will help astronomers identify planets around other stars that are capable of supporting life.
Conceptual image of this research: using Gamma Ray Bursts to determine distance in space. (Credit: NAOJ)
An international team of 23 researchers led by Maria Dainotti, Assistant Professor at the National Astronomical Observatory of Japan (NAOJ), has analyzed archive data for powerful cosmic explosions from the deaths of stars and found a new way to measure distances in the distant Universe.
With no landmarks in space, it is very difficult to get a sense of depth. One technique astronomers use is to look for “standard candles,” objects or events where the underlying physics dictate that the absolute brightness (what you would see if you were right next to it) is always the same.
By comparing this calculated absolute brightness to the apparent brightness (what is actually observed from Earth), it is possible to determine the distance to the standard candle, and by extension other objects in the same area. The lack of standard candles bright enough to be seen more than 11 billion light-years away has hindered research on the distance Universe. Gamma-Ray bursts (GRBs), bursts of radiation produced by the deaths of massive stars, are bright enough, but their brightness depends on the characteristics of the explosion.
Embracing the challenge of attempting to use these bright events as standard candles, the team analyzed archive data for the visible light observations of 500 GRBs taken by world-leading telescopes such as the Subaru Telescope (owned and operated by NAOJ), RATIR, and satellites such as the Neil Gehrels Swift Observatory.
RATIR is a multi-channel optical and infrared imager for the robotic 1.5-meter Johnson telescope at the Observatory Astronómico Nacional in Mexico.
Studying the light curve’s pattern of how the GRB brightens and dims over time, the team identified a class of 179 GRBs which have common features and have likely been caused by similar phenomena. From the characteristics of the light curves, the team was able to calculate a unique brightness and distance for each GRB which can be used as a cosmological tool.
These findings will provide new insights into the mechanics behind this class of GRBs, and provide a new standard candle for observing the distant Universe. Lead author Dainotti had previously found a similar pattern in X-ray observations of GRBs, but visible light observations have been revealed to be more accurate in determining cosmological parameters.
The National Institute of Natural Sciences [自然科学研究機構] (NINS) is an inter-university research institute corporation consisting of five member institutes: the National Astronomical Observatory (NAOJ), the National Institute for fusion Science (NIFS), the National Institute for Basic Biology (NIBB), the National Institute for Physiological Sciences (NIPS), and the Institutes for Molecular Sciences (IMS). NINS was established in April 2004 to bring about further development of the natural sciences in Japan.
The five institutes established under NINS are Japan’s main centers of academic research in their respective fields. These institutes cooperate actively as a base for interdisciplinary research in natural science with universities, university-affiliated research institutes, and inter-university research institutes to promote the formation of new research communities.
NINS established the Research Cooperation and Liaison Committee under the authority of the President, to discuss and plan matters of research cooperation. It has also established the Research Cooperation and Liaison Office, which is in charge of implementing plans made by the Research Cooperation and Liaison Committee. The Research Cooperation and Liaison Office has set “Imaging science” and “Hierarchy and Holism in Natural Science” as themes for cooperation across fields, and is promoting symposiums and other projects under these themes.
New simulation also shows gamma ray bursts are 10 times more rare than previously thought.
Jet wobbles as it escapes a collapsar.
A Northwestern University-led team of astrophysicists has developed the first-ever full 3D simulation of an entire evolution of a jet formed by a collapsing star, or a “collapsar.”
Because these jets generate gamma ray bursts (GRBs) — the most energetic and luminous events in the universe since the Big Bang — the simulations have shed light on these peculiar, intense bursts of light. Their new findings include an explanation for the longstanding question of why GRBs are mysteriously punctuated by quiet moments — blinking between powerful emissions and an eerily quiet stillness. The new simulation also shows that GRBs are even rarer than previously thought.
The new study was published today (June 29) in The Astrophysical Journal Letters. It marks the first full 3D simulation of the entire evolution of a jet — from its birth near the black hole to its emission after escaping from the collapsing star. The new model also is the highest-ever resolution simulation of a large-scale jet.
“These jets are the most powerful events in the universe,” said Northwestern’s Ore Gottlieb, who led the study. “Previous studies have tried to understand how they work, but those studies were limited by computational power and had to include many assumptions. We were able to model the entire evolution of the jet from the very beginning — from its birth by a black hole — without assuming anything about the jet’s structure. We followed the jet from the black hole all the way to the emission site and found processes that have been overlooked in previous studies.”
Gottlieb is a Rothschild Fellow in Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). He coauthored the paper with CIERA member Sasha Tchekhovskoy, an assistant professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences.
Weird wobbling
The most luminous phenomenon in the universe, GRBs emerge when the core of a massive star collapses under its own gravity to form a black hole. As gas falls into the rotating black hole, it energizes — launching a jet into the collapsing star. The jet punches the star until finally escaping from it, accelerating at speeds close to the speed of light. After breaking free from the star, the jet generates a bright GRB.
“The jet generates a GRB when it reaches about 30 times the size of the star — or a million times the size of the black hole,” Gottlieb said. “In other words, if the black hole is the size of a beach ball, the jet needs to expand over the entire size of France before it can produce a GRB.”
Due to the enormity of this scale, previous simulations have been unable to model the full evolution of the jet’s birth and subsequent journey. Using assumptions, all previous studies found that the jet propagates along one axis and never deviates from that axis.
But Gottlieb’s simulation showed something very different. As the star collapses into a black hole, material from that star falls onto the disk of magnetized gas that swirls around the black hole. The falling material causes the disk to tilt, which, in turn, tilts the jet. As the jet struggles to realign with its original trajectory, it wobbles inside the collapsar.
This wobbling provides a new explanation for why GRBs blink. During the quiet moments, the jet doesn’t stop — its emission beams away from Earth, so telescopes simply cannot observe it.
“Emission from GRBs is always irregular,” Gottlieb said. “We see spikes in emission and then a quiescent time that lasts for a few seconds or more. The entire duration of a GRB is about one minute, so these quiescent times are a non-negligible fraction of the total duration. Previous models were not able to explain where these quiescent times were coming from. This wobbling naturally gives an explanation to that phenomenon. We observe the jet when its pointing at us. But when the jet wobbles to point away from us, we cannot see its emission. This is part of Einstein’s theory of relativity.”
Rare becomes more rare
These wobbly jets also provide new insights into the rate and nature of GRBs. Although previous studies estimated that about 1% of collapsars produce GRBs, Gottlieb believes that GRBs are actually much more rare.
If the jet were constrained to moving along one axis, then it would only cover a thin slice of the sky — limiting the likelihood of observing it. But the wobbly nature of the jet means that astrophysicists can observe GRBs at different orientations, increasing the likelihood of spotting them. According to Gottlieb’s calculations, GRBs are 10 times more observable than previously thought, which means that astrophysicists are missing 10 times fewer GRBs than previously thought.
“The idea is that we observe GRBs on the sky in a certain rate, and we want to learn about the true rate of GRBs in the universe,” Gottlieb explained. “The observed and true rates are different because we can only see the GRBs that are pointing at us. That means we need to assume something about the angle that these jets cover on the sky, in order to infer the true rate of GRBs. That is, what fraction of GRBs we are missing. Wobbling increases the number of detectable GRBs, so the correction from the observed to true rate is smaller. If we miss fewer GRBs, then there are fewer GRBs overall in the sky.”
If this is true, Gottlieb posits, then most of the jets either fail to be launched at all or never succeed in escaping from the collapsar to produce a GRB. Instead, they remain buried inside.
Mixed energy
The new simulations also revealed that some of the magnetic energy in the jets partially converts to thermal energy. This suggests that the jet has a hybrid composition of magnetic and thermal energies, which produce the GRB. In a major step forward in understanding the mechanisms that power GRBs, this is the first time researchers have inferred the jet composition of GRBs at the time of emission.
“Studying jets enables us to ‘see’ what happens deep inside the star as it collapses,” Gottlieb said. “Otherwise, it’s difficult to learn what happens in a collapsed star because light cannot escape from the stellar interior. But we can learn from the jet emission — the history of the jet and the information that it carries from the systems that launch them.”
The major advance of the new simulation partially lies in its computational power. Using the code “H-AMR” on supercomputers at the Oak Ridge Leadership Computing Facility in Oak Ridge, Tennessee, the researchers developed the new simulation, which uses graphical processing units (GPUs) instead of central processing units (CPUs). Extremely efficient at manipulating computer graphics and image processing, GPUs accelerate the creation of images on a display.
Northwestern University is a private research university in Evanston, Illinois. Founded in 1851 to serve the former Northwest Territory, the university is a founding member of the Big Ten Conference.
On May 31, 1850, nine men gathered to begin planning a university that would serve the Northwest Territory.
Given that they had little money, no land and limited higher education experience, their vision was ambitious. But through a combination of creative financing, shrewd politicking, religious inspiration and an abundance of hard work, the founders of Northwestern University were able to make that dream a reality.
In 1853, the founders purchased a 379-acre tract of land on the shore of Lake Michigan 12 miles north of Chicago. They established a campus and developed the land near it, naming the surrounding town Evanston in honor of one of the University’s founders, John Evans. After completing its first building in 1855, Northwestern began classes that fall with two faculty members and 10 students.
Twenty-one presidents have presided over Northwestern in the years since. The University has grown to include 12 schools and colleges, with additional campuses in Chicago and Doha, Qatar.
Northwestern is known for its focus on interdisciplinary education, extensive research output, and student traditions. The university provides instruction in over 200 formal academic concentrations, including various dual degree programs. The university is composed of eleven undergraduate, graduate, and professional schools, which include the Kellogg School of Management, the Pritzker School of Law, the Feinberg School of Medicine, the Weinberg College of Arts and Sciences, the Bienen School of Music, the McCormick School of Engineering and Applied Science, the Medill School of Journalism, the School of Communication, the School of Professional Studies, the School of Education and Social Policy, and The Graduate School. As of fall 2019, the university had 21,946 enrolled students, including 8,327 undergraduates and 13,619 graduate students.
Valued at $12.2 billion, Northwestern’s endowment is among the largest university endowments in the United States. Its numerous research programs bring in nearly $900 million in sponsored research each year.
Northwestern’s main 240-acre (97 ha) campus lies along the shores of Lake Michigan in Evanston, 12 miles north of Downtown Chicago. The university’s law, medical, and professional schools, along with its nationally ranked Northwestern Memorial Hospital, are located on a 25-acre (10 ha) campus in Chicago’s Streeterville neighborhood. The university also maintains a campus in Doha, Qatar and locations in San Francisco, California, Washington, D.C. and Miami, Florida.
As of October 2020, Northwestern’s faculty and alumni have included 1 Fields Medalist, 22 Nobel Prize laureates, 40 Pulitzer Prize winners, 6 MacArthur Fellows, 17 Rhodes Scholars, 27 Marshall Scholars, 23 National Medal of Science winners, 11 National Humanities Medal recipients, 84 members of the American Academy of Arts and Sciences, 10 living billionaires, 16 Olympic medalists, and 2 U.S. Supreme Court Justices. Northwestern alumni have founded notable companies and organizations such as the Mayo Clinic, The Blackstone Group, Kirkland & Ellis, U.S. Steel, Guggenheim Partners, Accenture, Aon Corporation, AQR Capital, Booz Allen Hamilton, and Melvin Capital.
The foundation of Northwestern University can be traced to a meeting on May 31, 1850, of nine prominent Chicago businessmen, Methodist leaders, and attorneys who had formed the idea of establishing a university to serve what had been known from 1787 to 1803 as the Northwest Territory. On January 28, 1851, the Illinois General Assembly granted a charter to the Trustees of the North-Western University, making it the first chartered university in Illinois. The school’s nine founders, all of whom were Methodists (three of them ministers), knelt in prayer and worship before launching their first organizational meeting. Although they affiliated the university with the Methodist Episcopal Church, they favored a non-sectarian admissions policy, believing that Northwestern should serve all people in the newly developing territory by bettering the economy in Evanston.
John Evans, for whom Evanston is named, bought 379 acres (153 ha) of land along Lake Michigan in 1853, and Philo Judson developed plans for what would become the city of Evanston, Illinois. The first building, Old College, opened on November 5, 1855. To raise funds for its construction, Northwestern sold $100 “perpetual scholarships” entitling the purchaser and his heirs to free tuition. Another building, University Hall, was built in 1869 of the same Joliet limestone as the Chicago Water Tower, also built in 1869, one of the few buildings in the heart of Chicago to survive the Great Chicago Fire of 1871. In 1873 the Evanston College for Ladies merged with Northwestern, and Frances Willard, who later gained fame as a suffragette and as one of the founders of the Woman’s Christian Temperance Union (WCTU), became the school’s first dean of women (Willard Residential College, built in 1938, honors her name). Northwestern admitted its first female students in 1869, and the first woman was graduated in 1874.
Northwestern fielded its first intercollegiate football team in 1882, later becoming a founding member of the Big Ten Conference. In the 1870s and 1880s, Northwestern affiliated itself with already existing schools of law, medicine, and dentistry in Chicago. Northwestern University Pritzker School of Law is the oldest law school in Chicago. As the university’s enrollments grew, these professional schools were integrated with the undergraduate college in Evanston; the result was a modern research university combining professional, graduate, and undergraduate programs, which gave equal weight to teaching and research. By the turn of the century, Northwestern had grown in stature to become the third largest university in the United States after Harvard University and the University of Michigan.
Under Walter Dill Scott’s presidency from 1920 to 1939, Northwestern began construction of an integrated campus in Chicago designed by James Gamble Rogers, noted for his design of the Yale University campus, to house the professional schools. The university also established the Kellogg School of Management and built several prominent buildings on the Evanston campus, including Dyche Stadium, now named Ryan Field, and Deering Library among others. In the 1920s, Northwestern became one of the first six universities in the United States to establish a Naval Reserve Officers Training Corps (NROTC). In 1939, Northwestern hosted the first-ever NCAA Men’s Division I Basketball Championship game in the original Patten Gymnasium, which was later demolished and relocated farther north, along with the Dearborn Observatory, to make room for the Technological Institute.
After the golden years of the 1920s, the Great Depression in the United States (1929–1941) had a severe impact on the university’s finances. Its annual income dropped 25 percent from $4.8 million in 1930-31 to $3.6 million in 1933-34. Investment income shrank, fewer people could pay full tuition, and annual giving from alumni and philanthropists fell from $870,000 in 1932 to a low of $331,000 in 1935. The university responded with two salary cuts of 10 percent each for all employees. It imposed hiring and building freezes and slashed appropriations for maintenance, books, and research. Having had a balanced budget in 1930-31, the university now faced deficits of roughly $100,000 for the next four years. Enrollments fell in most schools, with law and music suffering the biggest declines. However, the movement toward state certification of school teachers prompted Northwestern to start a new graduate program in education, thereby bringing in new students and much needed income. In June 1933, Robert Maynard Hutchins, president of the University of Chicago, proposed a merger of the two universities, estimating annual savings of $1.7 million. The two presidents were enthusiastic, and the faculty liked the idea; many Northwestern alumni, however, opposed it, fearing the loss of their Alma Mater and its many traditions that distinguished Northwestern from Chicago. The medical school, for example, was oriented toward training practitioners, and alumni feared it would lose its mission if it were merged into the more research-oriented University of Chicago Medical School. The merger plan was ultimately dropped. In 1935, the Deering family rescued the university budget with an unrestricted gift of $6 million, bringing the budget up to $5.4 million in 1938-39. This allowed many of the previous spending cuts to be restored, including half of the salary reductions.
Like other American research universities, Northwestern was transformed by World War II (1939–1945). Regular enrollment fell dramatically, but the school opened high-intensity, short-term programs that trained over 50,000 military personnel, including future president John F. Kennedy. Northwestern’s existing NROTC program proved to be a boon to the university as it trained over 36,000 sailors over the course of the war, leading Northwestern to be called the “Annapolis of the Midwest.” Franklyn B. Snyder led the university from 1939 to 1949, and after the war, surging enrollments under the G.I. Bill drove dramatic expansion of both campuses. In 1948, prominent anthropologist Melville J. Herskovits founded the Program of African Studies at Northwestern, the first center of its kind at an American academic institution. J. Roscoe Miller’s tenure as president from 1949 to 1970 saw an expansion of the Evanston campus, with the construction of the Lakefill on Lake Michigan, growth of the faculty and new academic programs, and polarizing Vietnam-era student protests. In 1978, the first and second Unabomber attacks occurred at Northwestern University. Relations between Evanston and Northwestern became strained throughout much of the post-war era because of episodes of disruptive student activism, disputes over municipal zoning, building codes, and law enforcement, as well as restrictions on the sale of alcohol near campus until 1972. Northwestern’s exemption from state and municipal property-tax obligations under its original charter has historically been a source of town-and-gown tension.
Although government support for universities declined in the 1970s and 1980s, President Arnold R. Weber was able to stabilize university finances, leading to a revitalization of its campuses. As admissions to colleges and universities grew increasingly competitive in the 1990s and 2000s, President Henry S. Bienen’s tenure saw a notable increase in the number and quality of undergraduate applicants, continued expansion of the facilities and faculty, and renewed athletic competitiveness. In 1999, Northwestern student journalists uncovered information exonerating Illinois death-row inmate Anthony Porter two days before his scheduled execution. The Innocence Project has since exonerated 10 more men. On January 11, 2003, in a speech at Northwestern School of Law’s Lincoln Hall, then Governor of Illinois George Ryan announced that he would commute the sentences of more than 150 death-row inmates.
In the 2010s, a 5-year capital campaign resulted in a new music center, a replacement building for the business school, and a $270 million athletic complex. In 2014, President Barack Obama delivered a seminal economics speech at the Evanston campus.
Organization and administration
Governance
Northwestern is privately owned and governed by an appointed Board of Trustees, which is composed of 70 members and, as of 2011, has been chaired by William A. Osborn ’69. The board delegates its power to an elected president who serves as the chief executive officer of the university. Northwestern has had sixteen presidents in its history (excluding interim presidents). The current president, economist Morton O. Schapiro, succeeded Henry Bienen whose 14-year tenure ended on August 31, 2009. The president maintains a staff of vice presidents, directors, and other assistants for administrative, financial, faculty, and student matters. Kathleen Haggerty assumed the role of interim provost for the university in April 2020.
Students are formally involved in the university’s administration through the Associated Student Government, elected representatives of the undergraduate students, and the Graduate Student Association, which represents the university’s graduate students.
The admission requirements, degree requirements, courses of study, and disciplinary and degree recommendations for each of Northwestern’s 12 schools are determined by the voting members of that school’s faculty (assistant professor and above).
Northwestern University had a dental school from 1891 to May 31, 2001, when it closed.
Endowment
In 1996, Princess Diana made a trip to Evanston to raise money for the university hospital’s Robert H. Lurie Comprehensive Cancer Center at the invitation of then President Bienen. Her visit raised a total of $1.5 million for cancer research.
In 2003, Northwestern finished a five-year capital campaign that raised $1.55 billion, exceeding its fundraising goal by $550 million.
In 2014, Northwestern launched the “We Will” campaign with a fundraising goal of $3.75 billion. As of December 31, 2019, the university has received $4.78 billion from 164,026 donors.
Sustainability
In January 2009, the Green Power Partnership (sponsored by the EPA) listed Northwestern as one of the top 10 universities in the country in purchasing energy from renewable sources. The university matches 74 million kilowatt hours (kWh) of its annual energy use with Green-e Certified Renewable Energy Certificates (RECs). This green power commitment represents 30 percent of the university’s total annual electricity use and places Northwestern in the EPA’s Green Power Leadership Club. The Initiative for Sustainability and Energy at Northwestern (ISEN), supporting research, teaching and outreach in these themes, was launched in 2008.
Northwestern requires that all new buildings be LEED-certified. Silverman Hall on the Evanston campus was awarded Gold LEED Certification in 2010; Wieboldt Hall on the Chicago campus was awarded Gold LEED Certification in 2007, and the Ford Motor Company Engineering Design Center on the Evanston campus was awarded Silver LEED Certification in 2006. New construction and renovation projects will be designed to provide at least a 20% improvement over energy code requirements where feasible. At the beginning of the 2008–09 academic year, the university also released the Evanston Campus Framework Plan, which outlines plans for future development of the university’s Evanston campus. The plan not only emphasizes sustainable building construction, but also focuses on reducing the energy costs of transportation by optimizing pedestrian and bicycle access. Northwestern has had a comprehensive recycling program in place since 1990. The university recycles over 1,500 tons of waste, or 30% of all waste produced on campus, each year. All landscape waste at the university is composted.
Academics
Education and rankings
Northwestern is a large, residential research university, and is frequently ranked among the top universities in the United States. The university is a leading institution in the fields of materials engineering, chemistry, business, economics, education, journalism, and communications. It is also prominent in law and medicine. Accredited by the Higher Learning Commission and the respective national professional organizations for chemistry, psychology, business, education, journalism, music, engineering, law, and medicine, the university offers 124 undergraduate programs and 145 graduate and professional programs. Northwestern conferred 2,190 bachelor’s degrees, 3,272 master’s degrees, 565 doctoral degrees, and 444 professional degrees in 2012–2013. Since 1951, Northwestern has awarded 520 honorary degrees. Northwestern also has chapters of academic honor societies such as Phi Beta Kappa (Alpha of Illinois), Eta Kappa Nu, Tau Beta Pi, Eta Sigma Phi (Beta Chapter), Lambda Pi Eta, and Alpha Sigma Lambda (Alpha Chapter).
The four-year, full-time undergraduate program comprises the majority of enrollments at the university. Although there is no university-wide core curriculum, a foundation in the liberal arts and sciences is required for all majors; individual degree requirements are set by the faculty of each school. The university heavily emphasizes interdisciplinary learning, with 72% of undergrads combining two or more areas of study. Northwestern’s full-time undergraduate and graduate programs operate on an approximately 10-week academic quarter system with the academic year beginning in late September and ending in early June. Undergraduates typically take four courses each quarter and twelve courses in an academic year and are required to complete at least twelve quarters on campus to graduate. Northwestern offers honors, accelerated, and joint degree programs in medicine, science, mathematics, engineering, and journalism. The comprehensive doctoral graduate program has high coexistence with undergraduate programs.
Despite being a mid-sized university, Northwestern maintains a relatively low student to faculty ratio of 6:1.
Research
Northwestern was elected to the Association of American Universities in 1917 and is classified as an R1 university, denoting “very high” research activity. Northwestern’s schools of management, engineering, and communication are among the most academically productive in the nation. The university received $887.3 million in research funding in 2019 and houses over 90 school-based and 40 university-wide research institutes and centers. Northwestern also supports nearly 1,500 research laboratories across two campuses, predominately in the medical and biological sciences.
Northwestern is home to the Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern Institute for Complex Systems, Nanoscale Science and Engineering Center, Materials Research Center, Center for Quantum Devices, Institute for Policy Research, International Institute for Nanotechnology, Center for Catalysis and Surface Science, Buffet Center for International and Comparative Studies, the Initiative for Sustainability and Energy at Northwestern, and the Argonne/Northwestern Solar Energy Research Center among other centers for interdisciplinary research.
Student body
Northwestern enrolled 8,186 full-time undergraduate, 9,904 full-time graduate, and 3,856 part-time students in the 2019–2020 academic year. The freshman retention rate for that year was 98%. 86% of students graduated after four years and 92% graduated after five years. These numbers can largely be attributed to the university’s various specialized degree programs, such as those that allow students to earn master’s degrees with a one or two year extension of their undergraduate program.
The undergraduate population is drawn from all 50 states and over 75 foreign countries. 20% of students in the Class of 2024 were Pell Grant recipients and 12.56% were first-generation college students. Northwestern also enrolls the 9th-most National Merit Scholars of any university in the nation.
In Fall 2014, 40.6% of undergraduate students were enrolled in the Weinberg College of Arts and Sciences, 21.3% in the McCormick School of Engineering and Applied Science, 14.3% in the School of Communication, 11.7% in the Medill School of Journalism, 5.7% in the Bienen School of Music, and 6.4% in the School of Education and Social Policy. The five most commonly awarded undergraduate degrees are economics, journalism, communication studies, psychology, and political science. The Kellogg School of Management’s MBA, the School of Law’s JD, and the Feinberg School of Medicine’s MD are the three largest professional degree programs by enrollment. With 2,446 students enrolled in science, engineering, and health fields, the largest graduate programs by enrollment include chemistry, integrated biology, material sciences, electrical and computer engineering, neuroscience, and economics.
Athletics
Northwestern is a charter member of the Big Ten Conference. It is the conference’s only private university and possesses the smallest undergraduate enrollment (the next-smallest member, the University of Iowa, is roughly three times as large, with almost 22,000 undergraduates).
Northwestern fields 19 intercollegiate athletic teams (8 men’s and 11 women’s) in addition to numerous club sports. 12 of Northwestern’s varsity programs have had NCAA or bowl postseason appearances. Northwestern is one of five private AAU members to compete in NCAA Power Five conferences (the other four being Duke, Stanford, USC, and Vanderbilt) and maintains a 98% NCAA Graduation Success Rate, the highest among Football Bowl Subdivision schools.
In 2018, the school opened the Walter Athletics Center, a $270 million state of the art lakefront facility for its athletics teams.
Nickname and mascot
Before 1924, Northwestern teams were known as “The Purple” and unofficially as “The Fighting Methodists.” The name Wildcats was bestowed upon the university in 1924 by Wallace Abbey, a writer for the Chicago Daily Tribune, who wrote that even in a loss to the University of Chicago, “Football players had not come down from Evanston; wildcats would be a name better suited to “[Coach Glenn] Thistletwaite’s boys.” The name was so popular that university board members made “Wildcats” the official nickname just months later. In 1972, the student body voted to change the official nickname to “Purple Haze,” but the new name never stuck.
The mascot of Northwestern Athletics is “Willie the Wildcat”. Prior to Willie, the team mascot had been a live, caged bear cub from the Lincoln Park Zoo named Furpaw, who was brought to the playing field on game days to greet the fans. After a losing season however, the team decided that Furpaw was to blame for its misfortune and decided to select a new mascot. “Willie the Wildcat” made his debut in 1933, first as a logo and then in three dimensions in 1947, when members of the Alpha Delta fraternity dressed as wildcats during a Homecoming Parade.
Traditions
Northwestern’s official motto, “Quaecumque sunt vera,” was adopted by the university in 1890. The Latin phrase translates to “Whatsoever things are true” and comes from the Epistle of Paul to the Philippians (Philippians 4:8), in which St. Paul admonishes the Christians in the Greek city of Philippi. In addition to this motto, the university crest features a Greek phrase taken from the Gospel of John inscribed on the pages of an open book, ήρης χάριτος και αληθείας or “the word full of grace and truth” (John 1:14). Alma Mater is the Northwestern Hymn. The original Latin version of the hymn was written in 1907 by Peter Christian Lutkin, the first dean of the School of Music from 1883 to 1931. In 1953, then Director-of-Bands John Paynter recruited an undergraduate music student, Thomas Tyra (’54), to write an English version of the song, which today is performed by the Marching Band during halftime at Wildcat football games and by the orchestra during ceremonies and other special occasions.
Purple became Northwestern’s official color in 1892, replacing black and gold after a university committee concluded that too many other universities had used these colors. Today, Northwestern’s official color is purple, although white is something of an official color as well, being mentioned in both the university’s earliest song, Alma Mater (1907) (“Hail to purple, hail to white”) and in many university guidelines. The Rock, a 6-foot high quartzite boulder donated by the Class of 1902, originally served as a water fountain. It was painted over by students in the 1940s as a prank and has since become a popular vehicle of self-expression on campus. Armadillo Day, commonly known as Dillo Day, is the largest student-run music festival in the country. The festival is hosted every Spring on Northwestern’s Lakefront. Primal Scream is held every quarter at 9 p.m. on the Sunday before finals week. Students lean out of windows or gather in courtyards and scream to help relieve stress.
In the past, students would throw marshmallows during football games, but this tradition has since been discontinued.
Philanthropy
One of Northwestern’s most notable student charity events is Dance Marathon, the most established and largest student-run philanthropy in the nation. The annual 30-hour event is among the most widely-attended events on campus. It has raised over $1 million for charity every year since 2011 and has donated a total of $13 million to children’s charities since its conception.
The Northwestern Community Development Corps (NCDC) is a student-run organization that connects hundreds of student volunteers to community development projects in Evanston and Chicago throughout the year. The group also holds a number of annual community events, including Project Pumpkin, a Halloween celebration that provides over 800 local children with carnival events and a safe venue to trick-or-treat each year.
Many Northwestern students participate in the Freshman Urban Program, an initiative for students interested in community service to work on addressing social issues facing the city of Chicago, and the university’s Global Engagement Studies Institute (GESI) programs, including group service-learning expeditions in Asia, Africa, or Latin America in conjunction with the Foundation for Sustainable Development.
Several internationally recognized non-profit organizations were established at Northwestern, including the World Health Imaging, Informatics and Telemedicine Alliance, a spin-off from an engineering student’s honors thesis. Media
Print
Established in 1881, The Daily Northwestern is the university’s main student newspaper and is published on weekdays during the academic year. It is directed entirely by undergraduate students and owned by the Students Publishing Company. Although it serves the Northwestern community, the Daily has no business ties to the university and is supported wholly by advertisers. North by Northwestern is an online undergraduate magazine established in September 2006 by students at the Medill School of Journalism. Published on weekdays, it consists of updates on news stories and special events throughout the year. It also publishes a quarterly print magazine. Syllabus is the university’s undergraduate yearbook. It is distributed in late May and features a culmination of the year’s events at Northwestern. First published in 1885, the yearbook is published by Students Publishing Company and edited by Northwestern students. Northwestern Flipside is an undergraduate satirical magazine. Founded in 2009, it publishes a weekly issue both in print and online. Helicon is the university’s undergraduate literary magazine. Established in 1979, it is published twice a year: a web issue is released in the winter and a print issue with a web complement is released in the spring. The Protest is Northwestern’s quarterly social justice magazine.
The Northwestern division of Student Multicultural Affairs supports a number of publications for particular cultural groups including Ahora, a magazine about Hispanic and Latino/a culture and campus life; Al Bayan, published by the Northwestern Muslim-cultural Student Association; BlackBoard Magazine, a magazine centered around African-American student life; and NUAsian, a magazine and blog on Asian and Asian-American culture and issues. The Northwestern University Law Review is a scholarly legal publication and student organization at Northwestern University School of Law. Its primary purpose is to publish a journal of broad legal scholarship. The Law Review publishes six issues each year. Student editors make the editorial and organizational decisions and select articles submitted by professors, judges, and practitioners, as well as student pieces. The Law Review also publishes scholarly pieces weekly on the Colloquy. The Northwestern Journal of Technology and Intellectual Property is a law review published by an independent student organization at Northwestern University School of Law. The Northwestern Interdisciplinary Law Review is a scholarly legal publication published annually by an editorial board of Northwestern undergraduates. Its mission is to publish interdisciplinary legal research, drawing from fields such as history, literature, economics, philosophy, and art. Founded in 2008, the journal features articles by professors, law students, practitioners, and undergraduates. It is funded by the Buffett Center for International and Comparative Studies and the Office of the Provost.
Web-based
Established in January 2011, Sherman Ave is a humor website that often publishes content on Northwestern student life. Most of its staff writers are current Northwestern undergraduates writing under various pseudonyms. The website is popular among students for its interviews of prominent campus figures, Freshman Guide, and live-tweeting coverage of football games. In Fall 2012, the website promoted a satiric campaign to end the Vanderbilt University football team’s custom of clubbing baby seals. Politics & Policy is dedicated to the analysis of current events and public policy. Established in 2010 by students at the Weinberg College of Arts and Sciences, School of Communication, and Medill School of Journalism, the publication reaches students on more than 250 college campuses around the world. Run entirely by undergraduates, it is published several times a week and features material ranging from short summaries of events to extended research pieces. The publication is financed in part by the Buffett Center. Northwestern Business Review is a campus source for business news. Founded in 2005, it has an online presence as well as a quarterly print schedule. TriQuarterly Online (formerly TriQuarterly) is a literary magazine published twice a year featuring poetry, fiction, nonfiction, drama, literary essays, reviews, blog posts, and art. The Queer Reader is Northwestern’s first radical feminist and LGBTQ+ publication.
Radio, film, and television
WNUR (89.3 FM) is a 7,200-watt radio station that broadcasts to the city of Chicago and its northern suburbs. WNUR’s programming consists of music (jazz, classical, and rock), literature, politics, current events, varsity sports (football, men’s and women’s basketball, baseball, softball, and women’s lacrosse), and breaking news on weekdays. Studio 22 is a student-run production company that produces roughly ten films each year. The organization financed the first film Zach Braff directed, and many of its films have featured students who would later go into professional acting, including Zach Gilford of Friday Night Lights. Applause for a Cause is currently the only student-run production company in the nation to create feature-length films for charity. It was founded in 2010 and has raised over $5,000 to date for various local and national organizations across the United States. Northwestern News Network is a student television news and sports network, serving the Northwestern and Evanston communities. Its studios and newsroom are located on the fourth floor of the McCormick Tribune Center on Northwestern’s Evanston campus. NNN is funded by the Medill School of Journalism.
Caltech/MIT Advanced aLigo detector installation Livingston, LA. installation. Credit: Caltech. 
Caltech/MIT Advanced aLigo Hanford, WA. installation. Credit: Caltech. 
VIRGO Gravitational Wave interferometer installation, near Pisa (IT).
KAGRA Large-scale Cryogenic Gravitational Wave Telescope Project installation (JP). 
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