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  • richardmitnick 2:06 pm on September 20, 2019 Permalink | Reply
    Tags: , , , CfA, , , , The next-generation Event Horizon Telescope (ngEHT)   

    From Harvard-Smithsonian Center for Astrophysics: “Announcement of the Next Generation Event Horizon Telescope Design Program” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    September 20, 2019
    Tyler Jump
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    +1 617-495-7462
    tyler.jump@cfa.harvard.edu

    1

    The National Science Foundation has just announced the award of a $12.7M grant to architect and design a next-generation Event Horizon Telescope (ngEHT) to carry out a program of transformative black hole science.

    Led by Principal Investigator Shep Doeleman at the Center for Astrophysics | Harvard and Smithsonian (CfA), the new ngEHT award will fund design and prototyping efforts by researchers at several US institutes. These include Dr. Gopal Narayanan at University of Massachusetts, Amherst, Dr. Vincent Fish at the MIT Haystack Observatory, and Drs. Katherine L. (Katie) Bouman and Gregg Hallinan at Caltech. At the CfA, Drs. Michael Johnson, Jonathan Weintroub and Lindy Blackburn are co-Principal Investigators of the ngEHT program.

    On April 10th, 2019, the International Event Horizon Telescope Collaboration released the first image of a supermassive black hole. A bright ring of emission at the heart of the Virgo A galaxy revealed a black hole, known as Messier 87, that has the mass of 6.5 billion Suns.

    Messier 87 supermassive black hole from the EHT

    Einstein’s theory of gravity passed this new test in spectacular fashion in this extreme cosmic laboratory. For this work, the EHT Collaboration will receive the Breakthrough Prize in Fundamental Physics this November.

    Black holes, objects with gravity so strong that light cannot escape, are now accessible to direct imaging. More precise tests of gravity can now be contemplated, and the processes by which supermassive black holes energize the brightness and dynamics of most galaxy cores can be studied in detail. The next-generation EHT (ngEHT) will sharpen the focus on black holes, and let researchers move from still-imagery to real-time videos of space-time at the event horizon.

    “As with all great discoveries, the first black hole image was just the beginning,” says Doeleman, Founding Director of the EHT. “Imagine being able to see a black hole evolve before your eyes. The ngEHT will give us front-row seats to one of the Universe’s most spectacular shows.”

    Sparked by this major investment, the ngEHT is expected to attract additional international support and participation by the broad EHT community. The ngEHT award is aimed at solving the formidable technical and algorithmic challenges required to significantly expand the capability of the EHT.

    The first Messier 87 black hole images were made using the technique of Very Long Baseline Interferometry (VLBI), in which an array of radio dishes around the world is combined to form an Earth-sized virtual telescope.

    Event Horizon Telescope Array

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)


    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    Future Array/Telescopes

    IRAM NOEMA in the French Alps on the wide and isolated Plateau de Bure at an elevation of 2550 meters, the telescope currently consists of ten antennas, each 15 meters in diameter.interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

    NSF CfA Greenland telescope


    Greenland Telescope

    ARO 12m Radio Telescope, Kitt Peak National Observatory, Arizona, USA, Altitude 1,914 m (6,280 ft)


    ARO 12m Radio Telescope

    By exploring new dish designs and locations, the ngEHT effort will plan the architecture for a new array with roughly double the number of sites worldwide.

    “The EHT observations demand unusually dry atmospheric conditions typically found at high altitudes. Identifying sites that meet this demand and deploying new dishes will vastly improve the EHT array’s black hole imaging ability,” says Dr. Jonathan Weintroub.

    In addition to new dishes, the ngEHT will incorporate an existing telescope at Caltech’s Owen’s Valley Radio Observatory (OVRO) and will upgrade the Large Millimeter Telescope Alfonso Serrano (LMT) in Mexico. “With its large aperture and central geographic location, the LMT is crucial to the next generation EHT effort. Planned enhancements to the LMT’s performance using MSRI funds will improve the EHT sensitivity over long observing campaigns,” notes Dr. Gopal Narayanan.

    Caltech Owens Valley Radio Observatory, located near Big Pine, California (US) in Owens Valley, Altitude1,222 m (4,009 ft)

    New technologies will, in turn, allow the ngEHT to expand the swath of radio frequencies it uses to photograph the event horizon. High speed recording systems that capture radio waves from the black hole will transfer data to central locations where they can be merged in a process that is analogous to the mirror in an optical telescope reflecting light to a single focus.

    “Currently, the EHT records about 10 PetaBytes of data each session,” according to Dr. Vincent Fish. “With planned higher data rates and the inclusion of new observatories, EHT data volumes could exceed 100 PetaBytes. Part of this project will be to investigate how to leverage advances in commercial technology to cost-effectively record and transport such a large volume of data.”

    The process of combining and analyzing data from around the globe demands high-performance computers and software that align signals from each EHT site to a fraction of a trillionth of a second. “The ngEHT pushes the boundaries in VLBI data complexity, along with the demands of models that seamlessly link the antennas together into a single Earth-size telescope,” says Dr. Lindy Blackburn.

    By filling in the Earth-sized lens with many new geographic locations, the ngEHT program will be able to harness new powerful algorithms to turn the incredible data volumes into images and even movies.

    “Our own Milky Way is host to a supermassive black hole that evolves dramatically over the course of a night. We are developing new methods, which incorporate emerging ideas from machine learning and computational imaging, in order to make the very first movies of gas spiraling towards an event horizon,” says Dr. Katie Bouman

    The goal of the EHT is to address some of the greatest mysteries and deepest questions about black holes.

    “Despite decades of study, some of the most basic questions about black holes remain untested,” says Dr. Michael Johnson. “With the ngEHT, we will be able to study how black holes act as powerful cosmic engines, energizing a swirling bath of infalling plasma and efficiently pouring unimaginable amounts of energy into narrow jets that pierce entire galaxies.”

    Doeleman is optimistic about the prospects of new discoveries with the ngEHT. “A decade ago we predicted we would be able to see a black hole. Now we estimate that over a billion people have seen the first image, and the Breakthrough Prize shows the impact it is having across the sciences. Through the ngEHT we are setting our sights high again, aiming to bring humanity even closer to the event horizon.”

    Learn more here: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1935980

    From The National Science Foundation:

    The Event Horizon Telescope (EHT) recently made the first direct image of a black hole, an image seen by billions of people around the world. Both the scientific community and the general the public were galvanized by this result. The program funded here is a design project to plan a greatly enhanced EHT (EHT-II), one with 7-8 additional telescopes placed around the world in locations designed to maximize imaging speed, dynamic range, and fidelity. The much faster snapshot mode of this combination will allow rapid tracking of changes near the black hole event horizon, allowing for the first time ever the creation of movies directly showing the dynamics of extreme gravity environments. The greater imaging power will also address long-standing fundamental questions such as how matter is blasted away from a black hole in the form of relativistic jets. Broader impacts include a National Air and Space Museum exhibit, and training of students in instrumentation development.

    Instead of relying on existing large facilities to form the Very Long Baseline Interferometry (VLBI) array, as the existing EHT has done, this design program will consider engineering and placement of small-diameter dishes that optimally fill out an Earth sized virtual telescope, tailored precisely for science objectives. By roughly doubling the number of dishes in the array through cost-effective use of small dishes, the EHT-II will be capable of making the first real-time movies of supermassive black holes. The Large Millimeter Telescope in Mexico, in collaboration with the University of Massachusetts Amherst, will serve as a testbed for advanced dual frequency receivers that will be developed as part of this design initiative.

    This project is supported by the Foundation-wide Mid-scale Research Infrastructure program. The project will be managed by the Division of Astronomical Sciences within the Directorate for Mathematics and Physical Sciences.

    This award reflects NSF’s statutory mission and has been deemed worthy of support through evaluation using the Foundation’s intellectual merit and broader impacts review criteria.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 1:16 pm on August 16, 2019 Permalink | Reply
    Tags: "Spotting Merging Galaxies", , , , CfA, , Over thirty years ago the Infrared Astronomy Satellite discovered that the universe contained many extremely luminous galaxies some more than a thousand times brighter than our own Milky Way., These galaxies are practically invisible at optical wavelengths.   

    From Harvard-Smithsonian Center for Astrophysics: “Spotting Merging Galaxies” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    Over thirty years ago, the Infrared Astronomy Satellite discovered that the universe contained many extremely luminous galaxies, some more than a thousand times brighter than our own Milky Way, but which are practically invisible at optical wavelengths.

    1
    NASA Infrared Astronomy Satellite

    These galaxies are powered by bursts of star formation buried deep within clouds of dust and gas. The dust absorbs the ultraviolet light while radiating at infrared wavelengths. In many cases the hyperactivity was triggered by a collisional encounter between galaxies that facilitated the collapse of interstellar gas into new stars.

    Collisions between galaxies are common. Indeed, most galaxies have probably been involved in one or more encounters during their lifetimes, making these interactions an important phase in galaxy evolution and the formation of stars in the universe. The Milky Way, for example, is bound by gravity to the Andromeda galaxy and is approaching it at a speed of about 50 kilometers per second; we are expected to meet in another billion years or so.

    Milkdromeda -Andromeda on the left-Earth’s night sky in 3.75 billion years-NASA

    In the local universe about five percent of galaxies are currently in a merger, and mergers usually can be easily identified by the visible morphological distortions they produce such as tidal tails sweeping out from the galactic discs.

    Not all infrared luminous galaxies show such distortions, however, and the issue of identifying (and classifying) mergers becomes especially problematic for studies of earlier cosmic epochs when the star formation rates were much higher than today, and when the merger rate of galaxies was also higher. (Moreover, such systems are preferentially discovered in deep galaxy surveys precisely because they are so luminous.) But galaxies in the distant cosmos are too remote to detect spatial signatures like tidal arms (at least with current telescopes). It is possible that other processes besides merger-induced star formation are lighting up some of these bright galaxies, for example accreting supermassive black holes can emit copious amounts of ultraviolet radiation. Because of such cases, estimates of star formation in the early universe based on luminosity measurements alone could be incorrect.

    CfA astronomer Lars Hernquist is a pioneer in the development of computer simulations of merging galaxies. Several years ago he and a team of colleagues produced a massive new simulation of the formation and evolution of galaxies in the universe, called Illustris.

    In a new paper [MNRAS] based on Ilustris simulated images of merger galaxies, the astronomers [Gregory F. Snyder, Vicente Rodriguez-Gomez, Jennifer M. Lotz, Paul Torrey, Amanda C.N. Quirk, Lars Hernquist, Mark Vogelsberger and Peter E. Freeman] present a way to help identify when imaged systems are mergers.

    They created about one million synthetic Hubble and James Webb Space Telescope images from their simulated mergers, and then looked for common morphological indicators of merging. They developed an algorithm that successfully identified mergers at roughly a seventy percent level of completeness out to distances of as much as eighty-five billion light-years (the current distance value), corresponding to light dating from the epoch about 2 billion years after the big bang.

    Results from the algorithm indicated that spatial features associated with strong central concentrations (or bulges) were most important for selecting past mergers, while double nuclei and asymmetries were most important for selecting future mergers (that is, sometime in the next 250 million years). The new algorithm will be particularly valuable when applied to future Webb images of very distant mergers.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 1:06 pm on July 30, 2019 Permalink | Reply
    Tags: "A Stellar Stream in the Milky Way Provides Evidence of Dark Substructure", , , , CfA, ,   

    From Harvard-Smithsonian Center for Astrophysics: “A Stellar Stream in the Milky Way Provides Evidence of Dark Substructure” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    July 29, 2019
    Amy Oliver, Public Affairs Officer
    amy.oliver@cfa.harvard.edu
    +1-520-879-4406
    mobile: +1-801-783-9067

    1
    The colors of the stars in this GD-1 stellar stream model overlaid on a Gaia flux map show how the star’s orbits were affected by the impact of the unknown dark substructure with white representing a large difference and dark red representing almost no difference. The stream’s orbit is overplotted in the foreground. Ana Bonaca, ESA, Gaia.

    Scientists at the Center for Astrophysics | Harvard & Smithsonian have observed what may be evidence of dark matter interfering with a stellar stream in the Milky Way galaxy.

    For scientists and non-scientists alike, the discovery tells an exciting, edge-of-your-seat story. “We know that 90% of the mass in our universe is invisible. We don’t know what it is, but we’re curious,” said Dr. Ana Bonaca, ITC Fellow at the CfA and lead author of the study. “Stellar streams, which are what we’re studying here, tell us the story of our galaxy. They are so long and thin that they are sensitive to the tiniest disturbances as they orbit through the galaxy. Our findings are that…in action.”

    Gaia, a mission of the European Space Agency (ESA), had a second data release in April 2018, which provided the basis for a new study of GD-1, the longest and most visible thin stellar stream in the Milky Way.

    ESA/GAIA satellite

    Typically, stars are distributed close to uniformly along such streams, so scientists immediately noticed that some of the stars in the GD-1 stream were not behaving as expected.

    “Stellar streams were thought to be more or less smooth in appearance, but GD-1 has gaps or regions of lower density along the stream. Close to one of these gaps there is an offshoot of misaligned stars,” said Adrian Price-Whelan, a coauthor of the study. “So first, we found something interesting that didn’t match what we expected to see, thanks to Gaia.”

    Stellar streams are associations of stars that once previously belonged to a dwarf galaxy or a globular cluster, but that were pulled out by the Milky Way’s tidal forces and stretched out into streams. In the standard picture, these streams are long, thin, and regular. The observed behavior in GD-1, however, could not be explained by tidal forces alone. Instead, Bonaca and collaborators used numerical simulations to show that the observed gap and spur features could be the result of the stream encountering a dense, massive object.

    “We considered a number of different objects as potential sources of perturbation, but none of them seemed to fit. We looked at the orbits of all known satellites in the Galaxy, but none crossed paths with GD-1 recently. We also considered whether molecular clouds could have done the damage because GD-1 crosses the Milky Way disk, but found they are not dense enough,” said Bonaca. “There is no obvious culprit.”

    With no known culprits, scientists have turned to more exotic explanations, and that’s big news for dark matter theorists. “One of the fundamental predictions of the dark-matter model is that there ought to be many concentrations or clusters of dark matter orbiting in the outskirts of our Galaxy. This stream looks like it can be used to find those small clumps of dark matter,” said David Hogg, a coauthor of the study. “Ruling out all other possibilities and actually detecting a small clump of dark matter would be a huge clue for understanding the nature of this important component of the Universe.”

    While Gaia data was used to make initial observations, the team has since conducted follow-up observations with Hectochelle—a multi-object echelle spectrograph—at the MMT Observatory, located at the Fred Lawrence Whipple Observatory at Mt. Hopkins in Arizona.


    CfA U Arizona Fred Lawrence Whipple Observatory Steward Observatory MMT Telescope at the summit of Mount Hopkins near Tucson, Arizona, USA, Altitude 2,616 m (8,583 ft)

    CfA Whipple Observatory, located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

    These new data will help in locating the dark substructure. In addition, Bonaca and other scientists have begun observing other stellar streams with unusual features.

    “When something passes close to a stellar stream, it leaves evidence behind, and we can see that something happened there. Even if it’s dark matter. Even if it’s invisible,” said Bonaca. “And if it is a clump of dark matter, there should be many of them. So we’re setting out to search for such oddities in other streams to find out for sure.”

    The results of the study are published in The Astrophysical Journal. In addition to Bonaca, the team consisted of CfA scientist Charlie Conroy; David W. Hogg representing the Centers for Cosmology and Particle Physics and for Data Science at New York University, Max-Planck-Institut fur Astronomie, and Flatiron Institute; and Adrian M. Price-Whelan at Princeton University and the Flatiron Institute.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 3:27 pm on July 23, 2019 Permalink | Reply
    Tags: , , , CfA, ,   

    From NASA Chandra Blog: “Exploring New Paths of Study with Chandra” 

    NASA Chandra Banner

    NASA/Chandra Telescope


    From NASA Chandra Blog

    2019-07-22
    Peter Edmonds, CXC

    1
    NASA/Chandra
    We make progress in astrophysics in a variety of ways. There is the sort that starts along a defined path, driven by meticulous proposals for telescope time or detailed science justifications for new missions. The plan is to advance knowledge by traveling further than others, or clearing a broader path. And then there are others.

    A big mission like NASA’s Chandra X-ray Observatory begins with plans for investigation along a slew of different directions and lines of study. At the time of Chandra’s launch on July 23rd, 1999, scientists thought these paths would mainly follow studies of galaxy clusters, dark matter, black holes, supernovas, and young stars. Indeed, in the last 20 years we’ve learned about black holes ripping stars apart (reported eg in 2004, 2011 and 2017), about a black hole generating the deepest known note in the universe, about dark matter being wrenched apart from normal matter in the famous Bullet Cluster and similar objects, about the discovery of the youngest supernova remnant in our galaxy, and much more.

    Bullet Cluster NASA Chandra NASA ESA Hubble


    NASA/ESA Hubble Telescope

    Progress in astrophysics can also be made when new paths of study suddenly open up. Three outstanding examples for Chandra are studies of gravitational wave events, dark energy and exoplanets. None of these fields existed before Chandra was conceived or built, but have now delivered some of our most exciting results.

    2
    Release: NASA Missions Catch FirstLight from a Gravitational-Wave Event

    The newest example is the study of X-rays produced by the aftermath of gravitational wave events. In 1999 the detection of gravitational waves seemed like a distant or even impossible goal for many astronomers. But the LIGO scientists kept improving their remarkably sensitive observatory until September 2015, when they detected a burst of gravitational waves from the merger of two black holes. Two black holes that merge are not expected to produce electromagnetic radiation, but the mergers of two neutron stars are. That is exactly what was as observed for the first time in August 2017 with LIGO and a slew of telescopes.


    VIRGO Gravitational Wave interferometer, near Pisa, Italy


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/eLISA the future of gravitational wave research

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2018


    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    UC Santa Cruz

    UC Santa Cruz

    UCSC All the Gold in the Universe

    A UC Santa Cruz special report

    Tim Stephens

    Astronomer Ryan Foley says “observing the explosion of two colliding neutron stars” –the first visible event ever linked to gravitational waves–is probably the biggest discovery he’ll make in his lifetime. That’s saying a lot for a young assistant professor who presumably has a long career still ahead of him.

    The first optical image of a gravitational wave source was taken by a team led by Ryan Foley of UC Santa Cruz using the Swope Telescope at the Carnegie Institution’s Las Campanas Observatory in Chile. This image of Swope Supernova Survey 2017a (SSS17a, indicated by arrow) shows the light emitted from the cataclysmic merger of two neutron stars. (Image credit: 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    A neutron star forms when a massive star runs out of fuel and explodes as a supernova, throwing off its outer layers and leaving behind a collapsed core composed almost entirely of neutrons. Neutrons are the uncharged particles in the nucleus of an atom, where they are bound together with positively charged protons. In a neutron star, they are packed together just as densely as in the nucleus of an atom, resulting in an object with one to three times the mass of our sun but only about 12 miles wide.

    “Basically, a neutron star is a gigantic atom with the mass of the sun and the size of a city like San Francisco or Manhattan,” said Foley, an assistant professor of astronomy and astrophysics at UC Santa Cruz.

    These objects are so dense, a cup of neutron star material would weigh as much as Mount Everest, and a teaspoon would weigh a billion tons. It’s as dense as matter can get without collapsing into a black hole.

    THE MERGER

    Like other stars, neutron stars sometimes occur in pairs, orbiting each other and gradually spiraling inward. Eventually, they come together in a catastrophic merger that distorts space and time (creating gravitational waves) and emits a brilliant flare of electromagnetic radiation, including visible, infrared, and ultraviolet light, x-rays, gamma rays, and radio waves. Merging black holes also create gravitational waves, but there’s nothing to be seen because no light can escape from a black hole.

    Foley’s team was the first to observe the light from a neutron star merger that took place on August 17, 2017, and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).

    ALL THE GOLD IN THE UNIVERSE

    It turns out that the origins of the heaviest elements, such as gold, platinum, uranium—pretty much everything heavier than iron—has been an enduring conundrum. All the lighter elements have well-explained origins in the nuclear fusion reactions that make stars shine or in the explosions of stars (supernovae). Initially, astrophysicists thought supernovae could account for the heavy elements, too, but there have always been problems with that theory, says Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz.

    The violent merger of two neutron stars is thought to involve three main energy-transfer processes, shown in this diagram, that give rise to the different types of radiation seen by astronomers, including a gamma-ray burst and a kilonova explosion seen in visible light. (Image credit: Murguia-Berthier et al., Science)

    A theoretical astrophysicist, Ramirez-Ruiz has been a leading proponent of the idea that neutron star mergers are the source of the heavy elements. Building a heavy atomic nucleus means adding a lot of neutrons to it. This process is called rapid neutron capture, or the r-process, and it requires some of the most extreme conditions in the universe: extreme temperatures, extreme densities, and a massive flow of neutrons. A neutron star merger fits the bill.

    Ramirez-Ruiz and other theoretical astrophysicists use supercomputers to simulate the physics of extreme events like supernovae and neutron star mergers. This work always goes hand in hand with observational astronomy. Theoretical predictions tell observers what signatures to look for to identify these events, and observations tell theorists if they got the physics right or if they need to tweak their models. The observations by Foley and others of the neutron star merger now known as SSS17a are giving theorists, for the first time, a full set of observational data to compare with their theoretical models.

    According to Ramirez-Ruiz, the observations support the theory that neutron star mergers can account for all the gold in the universe, as well as about half of all the other elements heavier than iron.

    RIPPLES IN THE FABRIC OF SPACE-TIME

    Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity, but until recently they were impossible to observe. LIGO’s extraordinarily sensitive detectors achieved the first direct detection of gravitational waves, from the collision of two black holes, in 2015. Gravitational waves are created by any massive accelerating object, but the strongest waves (and the only ones we have any chance of detecting) are produced by the most extreme phenomena.

    Two massive compact objects—such as black holes, neutron stars, or white dwarfs—orbiting around each other faster and faster as they draw closer together are just the kind of system that should radiate strong gravitational waves. Like ripples spreading in a pond, the waves get smaller as they spread outward from the source. By the time they reached Earth, the ripples detected by LIGO caused distortions of space-time thousands of times smaller than the nucleus of an atom.

    The rarefied signals recorded by LIGO’s detectors not only prove the existence of gravitational waves, they also provide crucial information about the events that produced them. Combined with the telescope observations of the neutron star merger, it’s an incredibly rich set of data.

    LIGO can tell scientists the masses of the merging objects and the mass of the new object created in the merger, which reveals whether the merger produced another neutron star or a more massive object that collapsed into a black hole. To calculate how much mass was ejected in the explosion, and how much mass was converted to energy, scientists also need the optical observations from telescopes. That’s especially important for quantifying the nucleosynthesis of heavy elements during the merger.

    LIGO can also provide a measure of the distance to the merging neutron stars, which can now be compared with the distance measurement based on the light from the merger. That’s important to cosmologists studying the expansion of the universe, because the two measurements are based on different fundamental forces (gravity and electromagnetism), giving completely independent results.

    “This is a huge step forward in astronomy,” Foley said. “Having done it once, we now know we can do it again, and it opens up a whole new world of what we call ‘multi-messenger’ astronomy, viewing the universe through different fundamental forces.”

    IN THIS REPORT

    Neutron stars
    A team from UC Santa Cruz was the first to observe the light from a neutron star merger that took place on August 17, 2017 and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)

    Graduate students and post-doctoral scholars at UC Santa Cruz played key roles in the dramatic discovery and analysis of colliding neutron stars.Astronomer Ryan Foley leads a team of young graduate students and postdoctoral scholars who have pulled off an extraordinary coup. Following up on the detection of gravitational waves from the violent merger of two neutron stars, Foley’s team was the first to find the source with a telescope and take images of the light from this cataclysmic event. In so doing, they beat much larger and more senior teams with much more powerful telescopes at their disposal.

    “We’re sort of the scrappy young upstarts who worked hard and got the job done,” said Foley, an untenured assistant professor of astronomy and astrophysics at UC Santa Cruz.

    David Coulter, graduate student

    The discovery on August 17, 2017, has been a scientific bonanza, yielding over 100 scientific papers from numerous teams investigating the new observations. Foley’s team is publishing seven papers, each of which has a graduate student or postdoc as the first author.

    “I think it speaks to Ryan’s generosity and how seriously he takes his role as a mentor that he is not putting himself front and center, but has gone out of his way to highlight the roles played by his students and postdocs,” said Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz and the most senior member of Foley’s team.

    “Our team is by far the youngest and most diverse of all of the teams involved in the follow-up observations of this neutron star merger,” Ramirez-Ruiz added.

    Charles Kilpatrick, postdoctoral scholar

    Charles Kilpatrick, a 29-year-old postdoctoral scholar, was the first person in the world to see an image of the light from colliding neutron stars. He was sitting in an office at UC Santa Cruz, working with first-year graduate student Cesar Rojas-Bravo to process image data as it came in from the Swope Telescope in Chile. To see if the Swope images showed anything new, he had also downloaded “template” images taken in the past of the same galaxies the team was searching.

    Ariadna Murguia-Berthier, graduate student

    “In one image I saw something there that was not in the template image,” Kilpatrick said. “It took me a while to realize the ramifications of what I was seeing. This opens up so much new science, it really marks the beginning of something that will continue to be studied for years down the road.”

    At the time, Foley and most of the others in his team were at a meeting in Copenhagen. When they found out about the gravitational wave detection, they quickly got together to plan their search strategy. From Copenhagen, the team sent instructions to the telescope operators in Chile telling them where to point the telescope. Graduate student David Coulter played a key role in prioritizing the galaxies they would search to find the source, and he is the first author of the discovery paper published in Science.

    Matthew Siebert, graduate student

    “It’s still a little unreal when I think about what we’ve accomplished,” Coulter said. “For me, despite the euphoria of recognizing what we were seeing at the moment, we were all incredibly focused on the task at hand. Only afterward did the significance really sink in.”

    Just as Coulter finished writing his paper about the discovery, his wife went into labor, giving birth to a baby girl on September 30. “I was doing revisions to the paper at the hospital,” he said.

    It’s been a wild ride for the whole team, first in the rush to find the source, and then under pressure to quickly analyze the data and write up their findings for publication. “It was really an all-hands-on-deck moment when we all had to pull together and work quickly to exploit this opportunity,” said Kilpatrick, who is first author of a paper comparing the observations with theoretical models.

    César Rojas Bravo, graduate student

    Graduate student Matthew Siebert led a paper analyzing the unusual properties of the light emitted by the merger. Astronomers have observed thousands of supernovae (exploding stars) and other “transients” that appear suddenly in the sky and then fade away, but never before have they observed anything that looks like this neutron star merger. Siebert’s paper concluded that there is only a one in 100,000 chance that the transient they observed is not related to the gravitational waves.

    Ariadna Murguia-Berthier, a graduate student working with Ramirez-Ruiz, is first author of a paper synthesizing data from a range of sources to provide a coherent theoretical framework for understanding the observations.

    Another aspect of the discovery of great interest to astronomers is the nature of the galaxy and the galactic environment in which the merger occurred. Postdoctoral scholar Yen-Chen Pan led a paper analyzing the properties of the host galaxy. Enia Xhakaj, a new graduate student who had just joined the group in August, got the opportunity to help with the analysis and be a coauthor on the paper.

    Yen-Chen Pan, postdoctoral scholar

    “There are so many interesting things to learn from this,” Foley said. “It’s a great experience for all of us to be part of such an important discovery.”

    Enia Xhakaj, graduate student

    IN THIS REPORT

    Scientific Papers from the 1M2H Collaboration

    Coulter et al., Science, Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source

    Drout et al., Science, Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

    Shappee et al., Science, Early Spectra of the Gravitational Wave Source GW170817: Evolution of a Neutron Star Merger

    Kilpatrick et al., Science, Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger

    Siebert et al., ApJL, The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source

    Pan et al., ApJL, The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source

    Murguia-Berthier et al., ApJL, A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

    Kasen et al., Nature, Origin of the heavy elements in binary neutron star mergers from a gravitational wave event

    Abbott et al., Nature, A gravitational-wave standard siren measurement of the Hubble constant (The LIGO Scientific Collaboration and The Virgo Collaboration, The 1M2H Collaboration, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, The Las Cumbres Observatory Collaboration, The VINROUGE Collaboration & The MASTER Collaboration)

    Abbott et al., ApJL, Multi-messenger Observations of a Binary Neutron Star Merger

    PRESS RELEASES AND MEDIA COVERAGE


    Watch Ryan Foley tell the story of how his team found the neutron star merger in the video below. 2.5 HOURS.

    Press releases:

    UC Santa Cruz Press Release

    UC Berkeley Press Release

    Carnegie Institution of Science Press Release

    LIGO Collaboration Press Release

    National Science Foundation Press Release

    Media coverage:

    The Atlantic – The Slack Chat That Changed Astronomy

    Washington Post – Scientists detect gravitational waves from a new kind of nova, sparking a new era in astronomy

    New York Times – LIGO Detects Fierce Collision of Neutron Stars for the First Time

    Science – Merging neutron stars generate gravitational waves and a celestial light show

    CBS News – Gravitational waves – and light – seen in neutron star collision

    CBC News – Astronomers see source of gravitational waves for 1st time

    San Jose Mercury News – A bright light seen across the universe, proving Einstein right

    Popular Science – Gravitational waves just showed us something even cooler than black holes

    Scientific American – Gravitational Wave Astronomers Hit Mother Lode

    Nature – Colliding stars spark rush to solve cosmic mysteries

    National Geographic – In a First, Gravitational Waves Linked to Neutron Star Crash

    Associated Press – Astronomers witness huge cosmic crash, find origins of gold

    Science News – Neutron star collision showers the universe with a wealth of discoveries

    UCSC press release
    First observations of merging neutron stars mark a new era in astronomy

    Credits

    Writing: Tim Stephens
    Video: Nick Gonzales
    Photos: Carolyn Lagattuta
    Header image: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
    Design and development: Rob Knight
    Project managers: Sherry Main, Scott Hernandez-Jason, Tim Stephens

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    Noted in the video but not in the article:

    NASA/Chandra Telescope

    NASA/SWIFT Telescope

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    Prompt telescope CTIO Chile

    NASA NuSTAR X-ray telescope

    See the full article here

    A Chandra observation two days after the merger failed to make a detection, but about a week later a source was discovered. These and additional observations taught us about the behavior and orientation of the jet that the neutron star merger produced.

    The interest in this X-ray detection was so intense that there was a race between three different teams to publish the early Chandra observations first. This was accompanied by a rush to publicly announce the full set of results from LIGO and telescopes across the electromagnetic spectrum, before too many smart science writers dug out the news from Twitter and other publicly available information.

    3
    Release: All in the Family: Kin ofGravitational-Wave Source Discovered

    Chandra detections of two likely neutron star mergers have been reported since August 2017 (in 2018 and 2019). These did not involve a detection of GWs, both because Advanced LIGO wasn’t yet operating, and because the events were likely too distant to be detectable even if it was. When Advanced LIGO and Virgo detect other neutron star mergers, and optical telescopes track them down, Chandra “Target of Opportunity” programs will kick in to study them. (TOOs, as they are called, are special cases made by scientists to interrupt the regularly scheduled observations in favor of one that is time sensitive and/or extremely important.) One is a large proposal and collaboration between three different teams, one aims to take a spectrum, another aims to observe a relatively nearby event, and a fourth involves joint observations with the VLA.

    Those who work on Chandra and many in the wider science community were very excited about this detection because it marked the first time that gravitational waves and electromagnetic radiation were observed together, as a new type of “multi-messenger” astrophysics. (Multi-messenger astrophysics involves at least two of the following messengers: electromagnetic radiation, gravitational waves, neutrinos and cosmic rays.) However, it did not represent the first instance of multi-messenger astrophysics, because both electromagnetic radiation and neutrinos had already been observed from the Sun and from Supernova 1987A. Chandra may have already got into the act with the observation of a flare from material very close to the supermassive black hole in the center of our Galaxy, as reported in 2014. An energetic neutrino observed with the IceCube detector may have originated from this flare.

    Another exciting new line of study has come from the discovery that the expansion of the universe is accelerating. The two key papers providing the first evidence for this surprising result were published in 1998 and 1999, just before Chandra launched. Both papers used distance measurements to supernova explosions over the last 5 billion or so years to follow the expansion. Since then a set of different techniques have been used to independently confirm and extend these results, including two involving Chandra observations of galaxy clusters. In one of them the distances to galaxy clusters were used to probe the expansion rate of the universe and another involved measuring the effects of accelerating expansion in slowing down the growth rate of galaxy clusters, in a type of cosmic arrested development. As explained in this article, if it wasn’t for accelerating expansion the universe would look very different from how it looks today.

    The work measuring the growth rate of galaxy clusters has led to independent tests of Einstein’s General Theory of Relativity over distances that are much greater than those of Earth-orbiting satellites. The confirmation of GR has added to the evidence that a mysterious force called “dark energy” is causing cosmic acceleration.

    4
    Release: Astronomers Find Dark EnergyMay Vary Over Time

    More recently, Chandra is being used with a new technique to probe cosmic expansion out to greater distances than are possible with supernova data. Astronomers have found tentative evidence that dark energy might be strengthening with time, but this result needs to be confirmed with more extensive use of Chandra data, a study that is currently underway, and independent work.

    The recently-launched European mission eROSITA will be taking a sensitive X-ray survey of the complete sky and will discover a huge number of galaxy clusters for follow-up studies of both dark energy and dark matter with Chandra.

    eRosita DLR MPG

    5
    Release: NASA’s Chandra Sees Eclipsing Planetin X-rays for First Time

    Many think the field of exoplanets studies started in 1995 with the detection of a hot Jupiter around the star 51 Pegasus, acclaimed as the first exoplanet discovered around a Sun-like star. (This was about the time that the grinding and polishing of Chandra’s grazing-incidence mirrors was completed.) Chandra observations have shown cases of the tail wagging the dog, where a planet is affecting the star it is orbiting, in one case by making the star appear unusually old, and in others causing it to behave like a much younger star, as reported in 2011 and 2013.

    Chandra observations have uncovered multiple examples of planets under assault by outside forces. They’ve found cases where radiation from the host star is evaporating the atmosphere of a close-in planet (from 2011 and 2013), where the powerful gravity of a white dwarf may have ripped a planet apart, a case of possible stellar or planetary cannibalism, and a case where a star may be devouring a young planet. Chandra data was also used to show that young stars much less massive than the Sun can unleash a torrent of X-ray radiation that may significantly shorten the lifetime of planet-forming disks surrounding these stars.

    We look forward to reporting more results in these three new fields, along with discoveries from X-ray astronomy’s traditional specialities. We also hope to see new fields appear, for fresh exploration with NASA’s premier X-ray mission.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

     
  • richardmitnick 1:06 pm on June 25, 2019 Permalink | Reply
    Tags: "The Low Density of Some Exoplanets is Confirmed", , , , CfA, , Kepler-9 and its planets Kepler-9b and Kepler-9c   

    From Harvard-Smithsonian Center for Astrophysics: “The Low Density of Some Exoplanets is Confirmed” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    June 21, 2019

    The Kepler mission and its extension, called K2, discovered thousands of exoplanets.

    NASA/Kepler Telescope, and K2 March 7, 2009 until November 15, 2018

    It detected them using the transit technique, measuring the dip in light intensity whenever an orbiting planet moved across the face of its host star as viewed from Earth.

    Planet transit. NASA/Ames

    Transits can not only measure the orbital period, they often can determine the size of the exoplanet from the detailed depth and shape of its transit curve and the host star’s properties. The transit method, however, does not measure the mass of the planet. The radial velocity method, by contrast, which measures the wobble of a host star under the gravitational pull of an orbiting exoplanet, allows for the measurement of its mass. Knowing a planet’s radius and mass allows for the determination of its average density, and hence clues to its composition.

    Radial Velocity Method-Las Cumbres Observatory

    About fifteen years ago, CfA astronomers and others realized that in planetary systems with multiple planets, the periodic gravitational tug of one planet on another will alter their orbital parameters. Although the transit method cannot directly measure exoplanet masses, it can detect these orbital variations and these can be modeled to infer masses. Kepler has identified hundreds of exoplanet systems with transit-timing variations, and dozens have been successfully modeled. Surprisingly, this procedure seemed to find a prevalence of exoplanets with very low densities. The Kepler-9 system, for example, appears to have two planets with densities respectively of 0.42 and 0.31 grams per cubic centimeter. (For comparison, the rocky Earth’s average density is 5.51 grams per cubic centimeter, water is, by definition, 1.0 grams per cubic centimeter, and the gas giant Saturn is 0.69 grams per cubic centimeter.) The striking results cast some doubt on one or more parts of the transit timing variation methodology and created a long-standing concern.

    CfA astronomers David Charbonneau, David Latham, Mercedes Lopez-Morales, and David Phillips, and their colleagues tested the reliability of the method by measuring the densities of the Kepler-9 planets using the radial velocity method, its two Saturn-like planets being among a small group of exoplanets whose masses can be measured (if just barely) with either technique.

    2
    An artist’s depiction of Kepler-9 and its planets Kepler-9b and Kepler-9c. NASA

    They used the HARPS-N spectrometer on the Telescopio Nazionale Galileo in La Palma in sixteen observing epochs; HARPS-N can typically measure velocity variations with an error as tiny as about twenty miles an hour. Their results confirm the very low densities obtained by the transit-timing method, and verify the power of the transit-variation method.

    Harps North at Telescopio Nazionale Galileo –

    Telescopio Nazionale Galileo a 3.58-meter Italian telescope, located at the Roque de los Muchachos Observatory on the island of La Palma in the Canary Islands, Spain, Altitude 2,396 m (7,861 ft)

    Science paper:
    HARPS-N Radial Velocities Confirm the Low Densities of the Kepler-9 Planets
    MNRAS

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 2:57 pm on June 7, 2019 Permalink | Reply
    Tags: "The Co-Evolution of Galaxies and Supermassive Black Holes", , , , CfA,   

    From Harvard-Smithsonian Center for Astrophysics: “The Co-Evolution of Galaxies and Supermassive Black Holes” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    1
    An Illustris-TNG simulation of the stellar content of the universe today on the largest scales showing a projection of stars across a 150 million light-years. Scientists using the code have been able to trace the co-evolution of galaxies and their supermassive black holes. The TNG Collaboration

    The formation and growth of galaxies in the early universe is a key research topic for future giant telescopes like the Giant Magellan Telescope and space missions like the James Webb Space Telescope.

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

    NASA/ESA/CSA Webb Telescope annotated

    Meanwhile, computer simulations of cosmic galaxy development have made considerable progress in our understanding. They show that details of galaxy development are closely tied to the properties of the galaxies, like their sizes and star formation rates. These properties are in turn regulated by the galaxies’ gas content, the gas motions (primarily the angular momentum), and some still uncertain mechanisms that regulate star formation like feedback from the nuclear black hole. Finally, there is growing evidence for correlations between the properties of a supermassive black hole and its host galaxy.

    Black holes with millions or even billions of solar masses are found in the centers of most galaxies. The most powerfully active nuclear black holes are in quasars and these have been spotted as far away as the epoch when the universe was less than a billion years old, suggesting that the galaxy- black hole symbiosis was already underway at this early time. Accreting black holes can emit powerful jets or winds that reverse the accretion and drive material outward, sometimes quenching the star formation. These and other lines of evidence help to clarify the co-evolution mechanisms between black holes and galaxies and reveal the joint evolution of the galaxy and the supermassive black hole populations.

    CfA astronomers Lars Hernquist and Rainer Weinberger and their colleagues used the large-scale hydrodynamic simulation called IllustrisTNG to trace the development of galaxies and their black holes. The code is able to model the evolution of a wide range of black hole and galaxy properties as the universe ages. They successfully reproduce the observed correlation between star formation rate and galaxy mass. They find, among numerous other trends, that quiescent galaxies (those no longer actively making stars) first go through a phase of shrinking in size before they undergo a quenching event; they also find that in the cosmic epoch of peak star formation (about ten billion years ago) as many as twenty percent of galaxies hosted an active supermassive black hole.

    science paper:
    Linking Galaxy Structural Properties and Star Formation Activity to Black Hole Activity with IllustrisTNG
    MNRAS

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 3:29 pm on May 11, 2019 Permalink | Reply
    Tags: "Suppressed Star Formation in the Early Universe", , , , CfA, , Massive cluster SPT-CLJ0421   

    From Harvard Smithsonian Center for Astrophysics: “Suppressed Star Formation in the Early Universe” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    May 10, 2019

    6
    A galaxy cluster map portraying the density of galaxies members in the massive cluster SPT-CLJ0421. Astronomers studying five such clusters in the epoch about 4.5 billion years after the big bang conclude that their star formation is quenched. Symbols show the positions of individual galaxies and the cross marks the position of the SPT detection. Credit: Strazzullo et al. 2019

    Massive clusters of galaxies, some with more mass than a hundred Milky Way galaxies, have been detected from cosmic epochs as early as about three billion years after the big bang.

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Map of voids and superclusters within 500 million light years from Milky Way 8/11/09 http://www.atlasoftheuniverse.com/nearsc.html Richard Powell

    These six images represent the potential for new images and discoveries housed in the Chandra Data Archive. To celebrate October as American Archive Month, these images – which include supernova remnants, pulsars, black holes, and clusters of galaxies – are being released. Each image represents data that are available to both the professional scientific community as well as the general public.

    Their ongoing star formation makes them bright enough to be detected at these distances. These kinds of clusters were predicted by simulations of cosmological evolution but their properties are very uncertain. Astronomers piecing together the evolution of stars in the universe are particularly interested in these clusters because of their abundance of stars and activity.

    Star formation in galaxies is by no means a steady process. Not only can there be bursts of activity, prompted perhaps by a collision with a neighboring galaxy, but the opposite can occur. Star formation can be self- limiting because its massive young stars produce winds and supernovae that can blow apart the natal molecular clouds and disable future star formation. Combined with the disruption induced by jets from an active nuclear supermassive black hole, this disruptive process is called quenching and is thought to be able to bring star formation to a halt. Whether or not this occurs in the early universe, and when and how it proceeds, is a key area of comic research.

    CfA astronomers Matt Ashby and Esra Bulbul are members of the South Pole Telescope (SPT) team that discovered and studies massive galaxy clusters in the early universe.

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including the University of Chicago, the University of California, Berkeley, Case Western Reserve University, Harvard/Smithsonian Astrophysical Observatory, the University of Colorado Boulder, McGill University, The University of Illinois at Urbana-Champaign, University of California, Davis, Ludwig Maximilian University of Munich, Argonne National Laboratory, and the National Institute for Standards and Technology. It is funded by the National Science Foundation.

    They recently completed a follow-up study of star formation and the stellar populations in most distant clusters found in the SPT surveys. Using the IRAC camera on the Spitzer Space Telescope along with the Hubble Space Telescope Wide Field camera, they probed five clusters located in the epoch about 4.5 billion years after the big bang, a time when galaxies in general were particularly active in producing new stars.

    IRAC camera on the Spitzer space telescope

    NASA/Spitzer Infrared Telescope

    NASA/ESA Hubble WFC3

    NASA/ESA Hubble Telescope

    Clusters of this size are exceedingly rare at these distances, and this is the first such study ever done of them. Using the infrared colors of the galaxies in the selected SPT clusters, the scientists were able to characterize the stars and the star formation activity. The scientists found that, curiously, during this epoch the massive clusters tend to host a mixture of galaxy types with quiescent galaxies being quite common. Apparently in these quiescent cluster members the quenching of star formation has already occurred. The astronomers conclude that star formation can be efficiently suppressed in the central regions of the most massive clusters even in these early cosmic epochs when the most intense star formation is occurring.

    Science paper
    Galaxy populations in the most distant SPT-SZ clusters
    Astronomy and Astrophysics

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 12:41 pm on April 24, 2019 Permalink | Reply
    Tags: CfA, ,   

    From Harvard-Smithsonian Center for Astrophysics: “CfA Plays Central Role In Capturing Landmark Black Hole Image” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    Peter Edmonds
    Center for Astrophysics | Harvard & Smithsonian
    +1 617-496-1917
    pedmonds@cfa.harvard.edu

    Tyler Jump
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    +1 617-495-7462
    tyler.jump@cfa.harvard.edu

    1
    Messier 87 supermassive black hole depiction

    April 10, 2019

    The first image of a black hole ever taken was released April 10, 2019. This monumental achievement was made possible, in part, by key leadership and funding from the Center for Astrophysics | Harvard & Smithsonian (CfA).

    The Event Horizon Telescope, or EHT, is a global array of radio telescopes involving dozens of institutions and hundreds of scientists. The breakthrough discovery by the EHT is an image of Messier 87’s (M87’s) supermassive black hole in the center of the Virgo galaxy cluster, 55 million light years away. This black hole contains 6.5 billion times the mass of our Sun.

    EHT map

    Six papers are being published in the Astrophysical Journal Letters [see link below] today to describe this groundbreaking result.

    “This fulfills our dream to take the first picture of a black hole,” said the CfA’s Sheperd (Shep) S. Doeleman, the Director of the EHT. “We now have access to a cosmic laboratory of extreme gravity where we can test Einstein’s theory of General Relativity and challenge our fundamental assumptions about space and time.”

    Black holes are extremely compressed cosmic objects, containing extraordinary amounts of mass within a tiny region. This mass is shrouded by an event horizon, that is, the boundary beyond which nothing – not even light – can escape from the black hole’s powerful gravitational pull.

    The presence of these objects affects their surroundings in extreme ways, including warping spacetime and heating surrounding material to hundreds of billions of degrees. General Relativity predicts that a black hole will cast a circular shadow upon this bright, glowing material. The newly released image of M87 from the EHT reveals this shadow.

    “For decades, we have studied how black holes swallow material and power the hearts of galaxies,” says Ramesh Narayan, a Harvard University professor and a leader in EHT theory work. “To finally see a black hole in action, bending its nearby light into a bright ring, is a breathtaking confirmation that supermassive black holes exist and match the appearance expected from our simulations.”

    While astronomers have studied black holes for many years, making an image requires a new telescope with unprecedented resolution so it can detect fine details. To create this, the EHT combines the signals from an array of eight existing telescopes around the globe, including the Submillimeter Array (SMA), located on Maunakea in Hawai’i. As CfA engineer, Jonathan Weintroub, explains: “The resolution of the EHT depends on the separation between the telescopes, termed the baseline, as well as the short millimeter radio wavelengths observed. The finest resolution in the EHT comes from the longest baseline, which for M87 stretches from Hawai’i to Spain.” Weintroub, who co-coordinates the EHT’s Instrument Development Group, added: “To optimize the long baseline sensitivity, making detections possible, we developed a specialized system which adds together the signals from all available SMA dishes on Maunakea. In this mode, the SMA acts as a single EHT station.”

    After separately recording the signals at all eight telescopes, the data are flown to [two] locations* to be computationally combined into what would be measured by an Earth-sized telescope.

    MIT Haystack Observatory, Westford, Massachusetts, USA, Altitude 131 m (430 ft)


    Max Planck Institute for Radio Astronomy Bonn Germany

    *MIT Haystack Observatory, Westford, Massachusetts, USA and Max Planck Institute for Radio Astronomy Bonn Germany.

    “The EHT records millions of gigabytes of data from many telescopes that weren’t originally designed to work together,” explains Lindy Blackburn, who led the EHT team for data processing and calibration. “We developed multiple pathways to process and calibrate the data, using new algorithms to computationally stabilize the Earth’s atmosphere and to precisely align the signals from all sites within trillionths of a second.”

    Turning the EHT data into an image required developing new methods and procedures. “We weren’t ready to publish our images until after trying to break them in every way possible,” says Andrew Chael, a Harvard graduate student at the CfA, who developed a new imaging software library for the EHT. “To confirm our results, we compared images among four independent groups of scientists using three different imaging methods.” These tests were designed and led by Katie Bouman, a CfA postdoc who received her PhD in electrical engineering and computer science. Bouman explains, “We’re a melting pot of astronomers, physicists, mathematicians and engineers, and that’s what it took to achieve something once thought impossible.”

    Katie Bouman of Harvard Smithsonian Observatory for Astrophysics, headed to Caltech, with EHT hard drives from Messier 87

    Michael Johnson, a CfA astrophysicist who directs local EHT science and imaging efforts, is excited for the future. “Our image reveals that this enormous black hole — large enough to engulf the solar system — anchors a jet that extends tens of thousands of light years. Expanding the EHT may enable movies that reveal the dynamics of this living system, showing how the jet draws its energy from the black hole.”

    Besides those listed above, many others at the CfA have contributed in countless and invaluable ways. The following CfA scientists and engineers are co-authors of all six of the papers: Mislav Baloković, Lindy Blackburn, Katie Bouman, Roger Brissenden, Andrew Chael, Shep Doeleman, Joseph Farah, Mark Gurwell, David James, Michael Johnson, Garrett Keating, Jim Moran, Ramesh Narayan, Daniel Palumbo, Nimesh Patel, Dominic Pesce, Alexander W. Raymond, Jonathan Weintroub, Maciek Wielgus, and Ken Young.

    A list of biographies for CfA scientists working on the EHT are located here.

    The EHT and many of its key scientists are funded by a mixture of public (i.e. taxpayer) sources such as the National Science Foundation (NSF) and the Smithsonian Institution (SI) as well as the generosity of private entities including the Templeton Foundation and the Gordon and Betty Moore Foundation (GBMF). The NSF has funded steady advancement of the EHT over more than a decade and SI, administered through SAO, has provided funding for seven years. Doeleman has grants from the NSF and also from the GBMF and the John Templeton Foundation. The GBMF funded key technical developments starting in 2012 and was foundational in building the SAO group.

    SAO is one of the 13 stakeholder institutes for the EHT Board, and the CfA hosts the Array Operations Center for EHT observations. The SMA is a joint project between the Smithsonian Institution and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) in Taiwan. The Greenland Telescope, funded by ASIAA and SAO, joined the EHT for its second observing run in April, 2018.

    For more information on the EHT and this groundbreaking result, visit http://www.eventhorizontelescope.org and follow @ehtelescope on social media. The website for the CfA, which is organized into six research divisions to study the origin, evolution, and ultimate fate of the Universe, is http://www.cfa.harvard.edu.

    The full set of Astrophysical Journal Letters are here:

    https://iopscience.iop.org/journal/2041-8205/page/Focus_on_EHT

    See the full article here .


    Katie Bouman takes the story to Caltech.


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    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 12:15 pm on April 24, 2019 Permalink | Reply
    Tags: "Scientists Use Asteroid to Measure Smallest Star Size to Date", , , , CfA, , ,   

    From Harvard-Smithsonian Center for Astrophysics: “Scientists Use Asteroid to Measure Smallest Star Size to Date” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    April 16, 2019

    Amy Oliver
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    Fred Lawrence Whipple Observatory
    +1 617-495-7462
    amy.oliver@cfa.harvard.edu

    Tyler Jump
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    +1 617-495-7462
    tyler.jump@cfa.harvard.edu

    1

    Scientists in the VERITAS (Very Energetic Radiation Imaging Telescope Array System) Collaboration have published a paper in Nature Astronomy journal detailing the results of their work with the VERITAS array—located at the Center for Astrophysics’ Fred Lawrence Whipple Observatory in Amado, Arizona—to measure the smallest apparent size of stars in the night sky known to date.

    CfA/VERITAS, a major ground-based gamma-ray observatory with an array of four 12m optical reflectors for gamma-ray astronomy in the GeV – TeV energy range. Located at Fred Lawrence Whipple Observatory,Mount Hopkins, Arizona, US in AZ, USA, Altitude 2,606 m (8,550 ft)

    Measurements taken using the VERITAS telescopes revealed the diameter of a giant star located 2,674 light years from Earth. Taken on February 22, 2018, at the Whipple Observatory, data revealed the star to be 11 times the diameter of Earth’s Sun. Using the four 12-m gamma-ray telescopes of VERITAS, the team collected 300 images per second to detect the diffraction pattern in the shadow sweeping past the telescopes as the star TYC 5517-227-1 was occulted by the 60-km asteroid Imprinetta. “From these data, the brightness profile of the diffraction pattern of the star was reconstructed with high accuracy,” said Dr. Michael Daniel, Operations Manager, VERITAS. “This allowed us to determine the actual diameter of the star, and determine it to be a red giant, although it could previously be classified as ambiguous.”

    Three months later, on May 22, 2018, the team repeated the experiment when asteroid Penelope—diameter 88-km—occulted star TYC 278-748-1 located 700 light years from Earth. “Using the same formula for data collection and calculations, we determined this star to be 2.17 times the diameter Earth’s Sun,” said Daniel. “This direct measurement allowed us to correct an earlier estimation that placed the star’s diameter at 1.415 times that of our sun.”

    With almost any star on the night sky too distant from Earth to be directly measured using even the best of optical telescopes, scientists overcame these limitations using diffraction, which occurs when an object, like an asteroid, passes in front of a star, making a shadow called an occultation. “The incredibly faint shadows of asteroids pass over us every day,” explained Dr. Tarek Hassan, DESY. “But the rim of the shadow isn’t perfectly sharp. Instead, wrinkles of light surround the central shadow, like water ripples.”

    For VERITAS scientists, however, the task was not as easy as turning telescopes to the sky. “Asteroid occultations are difficult to predict,” said Daniel. “The only chance to catch the diffraction pattern is to make very fast snapshots when the shadow of the occultation sweeps across the telescope.”

    Astronomers have similarly used this method— which measures to an angular diameter of roughly one milliarcsecond—to measure angular sizes of stars occulted by Earth’s moon. “The trouble is that not many telescopes are large enough for the occultation method to measure the diffraction pattern with confirmed accuracy over the turbulence in the Earth’s atmosphere,” said Daniel. “VERITAS telescopes are uniquely sensitive as we use them primarily for observing faint light from very-high-energy gamma rays and cosmic rays. While they do not produce images as elegant as those from traditional optical telescopes, they see and capture fast variations of light, and we estimate that they can analyze stars up to ten times farther away with extreme accuracy than optical telescopes using the lunar occultation method can.”

    At its conclusion, the pilot study resulted in the direct measurement of the size of a star at the smallest angular scale in the night sky to date, and established a new method to determine the angular diameter of stars.

    About VERITAS

    VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a ground-based array of four, 12-m optical reflectors for gamma-ray astronomy located at the Center for Astrophysics | Harvard & Smithsonian, Fred Lawrence Whipple Observatory in Amado, Arizona. VERITAS is the world’s most sensitive very-high-energy gamma-ray observatory, and it detects gamma rays via the extremely brief flashes of blue “Čerenkov” light they create when they are absorbed in the Earth’s atmosphere.

    VERITAS is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, and the Smithsonian Institution, and by NSERC in Canada.

    The VERITAS Collaboration consists of about 80 scientists from 20 institutions in the United States, Canada, Germany and Ireland.

    For more information about VERITAS visit http://veritas.sao.arizona.edu

    About DESY

    DESY is one of the world’s leading particle accelerator centers. Researchers use the large‐scale facilities at DESY to explore the microcosm in all its variety – ranging from the interaction of tiny elementary particles to the behavior of innovative nanomaterials and the vital processes that take place between biomolecules to the great mysteries of the universe. The accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. DESY is a member of the Helmholtz Association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
  • richardmitnick 2:52 pm on March 20, 2019 Permalink | Reply
    Tags: Arizona, , CfA, , Muon Hunters 2: Return of the Ring- launches new Zooniverse citizen science project on March 14th 2019., VERITAS (Very Energetic Radiation Imaging Telescope Array System) gamma-ray observatory—a part of the Center for Astrophysics | Harvard & Smithsonian at the Fred Lawrence Whipple Observatory in , Zooniverse- the largest online platform for collaborative volunteer research   

    From Harvard-Smithsonian Center for Astrophysics: “Astrophysicists Once Again Seek Public’s Help to Unmask Muons Disguised as Gamma Rays” 

    Harvard Smithsonian Center for Astrophysics


    From Harvard-Smithsonian Center for Astrophysics

    March 14, 2019

    Amy Oliver
    Public Affairs
    Fred Lawrence Whipple Observatory
    Center for Astrophysics | Harvard & Smithsonian
    amy.oliver@cfa.harvard.edu

    Tyler Jump
    Public Affairs
    Center for Astrophysics | Harvard & Smithsonian
    +1 617-495-7462

    Minneapolis, MN & Amado, AZ –
    Muon Hunters 2: Return of the Ring, launches new Zooniverse citizen science project on March 14th, 2019.

    1
    After achieving highly successful results with their citizen science project, Muon Hunters, in 2017, scientists from the VERITAS (Very Energetic Radiation Imaging Telescope Array System) gamma-ray observatory—a part of the Center for Astrophysics | Harvard & Smithsonian at the Fred Lawrence Whipple Observatory in Amado, Arizona, USA—collaboration are once again asking the public for help in identifying hundreds of thousands of ring patterns produced in the cameras at VERITAS.

    Scientists use VERITAS to study gamma rays—the most energetic radiation in the universe—in order to explore the most exotic and extreme processes and physical conditions in space, like black holes, supernovae, and pulsars.

    Like the original project, Muon Hunters 2: Return of the Ring, will engage citizen scientists to identify patterns from muons—elementary particles like electrons, but heavier—and distinguish them from those produced by gamma rays, which the telescopes are designed to detect.

    “At VERITAS, we’re searching for gamma rays, which have the shortest wavelengths and the highest energy of any portion of the electromagnetic spectrum,” said Dr. Michael Daniel, Operations Manager, VERITAS. Muons are background that we have to get rid of so that we can more easily identify gamma rays, but they’re also useful to help us calibrate our telescopes. That’s where Muon Hunters, and the citizen scientists behind it, come in.”

    New to Muon Hunters 2 is the manner in which data will be presented to citizen scientists. Muon Hunters 2 will present images in a grid pattern, rather than individually, to bring additional efficiency to the project.

    “This time around, we’re trying to make both the project and the telescopes more efficient,” said Dr. Lucy Fortson, University of Minnesota Physics and Astronomy Professor and VERITAS researcher. “We use a machine to help the people work more efficiently and the classifications we get from citizen scientists help the machine to work more efficiently, so it’s a virtuous loop. Scientists will use the images that citizen scientists have identified to better train their computer programs to automatically tell the difference between muons and gamma rays.”

    Muon Hunters 2: The Return of the Ring, is run by Zooniverse, the largest online platform for collaborative volunteer research, in conjunction with VERITAS. Citizen science projects at Zooniverse allow researchers to efficiently and effectively comb through large amounts of complex data utilizing the enthusiastic efforts of millions of volunteers from around the world. Other current Zooniverse projects include Snapshot Safari, in which volunteers identify wildlife to help scientists understand the diversity and dynamics of wildlife populations across the African continent.

    The original Muon Hunters project welcomed 6,107 citizen scientists who made 2,161,338 classifications of 135,000 objects. “We are hoping to have as many, if not more, classifications than we had in the original project,” said Fortson. “The more data we get, the more efficient we can be, and that’s great for both the scientists and the machines.”

    Citizen scientists can become Muon Hunters here.

    About VERITAS

    VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a ground-based array of four, 12-m optical reflectors for gamma-ray astronomy located at the Center for Astrophysics | Harvard & Smithsonian, Fred Lawrence Whipple Observatory in Amado, Arizona. VERITAS detects gamma rays via the extremely brief flashes of blue “Cherenkov” light they create when they are absorbed in the Earth’s atmosphere.

    VERITAS is supported by grants from the U.S. Department of Energy Office of Science, the U.S. National Science Foundation, and the Smithsonian Institution, and by NSERC in Canada.

    The VERITAS Collaboration consists of about 80 scientists from 20 institutions in the United States, Canada, Germany and Ireland.

    For more information about VERITAS visit http://veritas.sao.arizona.edu

    About Muon Hunters

    Muon Hunters is a citizen science-based data collection and identification project led by the University of Minnesota and Zooniverse. The project receives data from VERITAS telescopes and direct support from specific VERITAS collaborating institutions including the University of California-Los Angeles; University of California-Santa Cruz; McGill University, Canada; Deutsches Electron-Synchrotron Laboratory, Berlin, Germany; Barnard College/Columbia University; Cal State University – East Bay; University College Dublin, Ireland; and the Center for Astrophysics | Harvard & Smithsonian. In addition, Muon Hunters is supported by the ASTERICS program of the European Union.

    For more information about Muon Hunters, visit http://www.muonhunters.org

    For more information, contact:
    Dr. Lucy Fortson
    Zooniverse
    lffortson@gmail.com

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

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

     
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