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  • richardmitnick 5:54 pm on January 17, 2022 Permalink | Reply
    Tags: "Palomar Survey Instrument Analyzes Impact of Starlink Satellites", 5301 satellite streaks appear in archival images taken between November 2019 and September 2021., A team of researchers studied archival images captured NSF-funded Zwicky Transient Facility (ZTF)-an instrument that operates from Caltech's Palomar Observatory near San Diego., Astronomers have expressed concerns that that SpaceX satellites which can appear as streaks in telescope images could hamper their scientific observations., In 2019 0.5 percent of twilight images were affected and now almost 20 percent are affected., SpaceX has been launching an increasing number of internet satellites into orbit around Earth., , The scientists expect that nearly all of the ZTF images taken during twilight will contain at least one streak especially after the Starlink constellation reaches 10000 satellites a goal SpaceX hopes , The streaks are most apparent in so-called twilight observations-those taken at dawn or dusk-which are important for finding near-Earth asteroids that appear close to the sun in the sky., ZTF-Zwicky Transient Facility   

    From The California Institute of Technology (US): “Palomar Survey Instrument Analyzes Impact of Starlink Satellites” 

    Caltech Logo

    From The California Institute of Technology (US)

    January 17, 2022
    Whitney Clavin
    (626) 395‑1944
    wclavin@caltech.edu

    A study of archival images from Zwicky Transient Facility shows an increase in satellite streaks.

    1
    The streak from a Starlink satellite appears in this image of the Andromeda galaxy, taken by The Zwicky Transient Facility, or ZTF, during twilight on May 19, 2021. The image shows only one-sixteenth of ZTF’s full field of view. Credit: Caltech Optical Observatories/The Caltech NASA Infrared Processing and Analysis Center(US).

    Since 2019, SpaceX has been launching an increasing number of internet satellites into orbit around Earth. The satellite constellation, called Starlink, now includes nearly 1,800 members orbiting at altitudes of about 550 kilometers. Astronomers have expressed concerns that that these objects, which can appear as streaks in telescope images, could hamper their scientific observations.

    To quantify these effects, a team of researchers studied archival images captured by the National Science Foundation (NSF)-funded Zwicky Transient Facility (ZTF), an instrument that operates from Caltech’s Palomar Observatory near San Diego.

    Zwicky Transient Facility (ZTF) instrument installed on the 1.2m diameter Samuel Oschin Telescope at Palomar Observatory in California. Credit: Caltech Optical Observatories.

    Caltech Palomar Samuel Oschin 48 inch Telescope, located in San Diego County, California, U.S.A., altitude 1,712 m (5,617 ft). Credit: Caltech.

    ZTF scans the entire night sky every two days, cataloguing cosmic objects that explode, blink, or otherwise change over time. This includes everything from supernovae to near-Earth asteroids. The Zwicky team members say they decided to specifically study the effects of Starlink satellites because they currently represent the largest low-Earth orbit, or LEO, constellation, and they have well-characterized orbits.

    The findings, reported in the January 17 issue of The Astrophysical Journal Letters, shows 5301 satellite streaks appear in archival images taken between November 2019 and September 2021. The streaks are most apparent in so-called twilight observations-those taken at dawn or dusk-which are important for finding near-Earth asteroids that appear close to the sun in the sky. ZTF has discovered several asteroids of this nature, including 2020 AV2, the first asteroid spotted with an orbit that fits entirely within the orbit of Venus.

    “In 2019 0.5 percent of twilight images were affected, and now almost 20 percent are affected,” says Przemek Mróz, study lead author and a former Caltech postdoctoral scholar who is now at The University of Warsaw [Uniwersytet Warszawski](PL).

    In the future, the scientists expect that nearly all of the ZTF images taken during twilight will contain at least one streak, especially after the Starlink constellation reaches 10,000 satellites, a goal SpaceX hopes to reach by 2027.

    “We don’t expect Starlink satellites to affect non-twilight images, but if the satellite constellation of other companies goes into higher orbits, this could cause problems for non-twilight observations,” Mróz says.

    Yet despite the increase in image streaks, the new report notes that ZTF science operations have not been strongly affected. Study co-author Tom Prince, the Ira S. Bowen Professor of Physics, Emeritus, at Caltech, says the paper shows a single streak affects less than one-tenth of a percent of the pixels in a ZTF image.

    “There is a small chance that we would miss an asteroid or another event hidden behind a satellite streak, but compared to the impact of weather, such as a cloudy sky, these are rather small effects for ZTF.”

    Prince says that software can be developed to help mitigate potential problems; for example, software could predict the locations of the Starlink satellites and thus help astronomers avoid scheduling an observation when one might be in the field of view. Software can also assess whether a passing satellite may have affected an astronomical observation, which would allow astronomers to mask or otherwise reduce the negative effects of the streaks.

    The new study also looked at the effectiveness of visors on the Starlink satellites, which SpaceX added beginning in 2020 to block sunlight from reaching the spacecraft. According to the ZTF observations, the visors reduce the satellite brightness by a factor of about five. That dims the satellites down to an apparent brightness level of 6.8 magnitude (the brightest stars are first magnitude, and the faintest stars we can see with our eyes are about sixth magnitude).

    This is still not dim enough to meet standards outlined by the Satellite Constellations 1 (SATCON1) workshop in 2020, a gathering sponsored by The NSF NOIRLab [National Optical-Infrared Astronomy Research Laboratory](US) and The American Astronomical Society (US) to bring together astronomers, policymakers, and other experts to discuss the impact of large satellite constellations on astronomy and society. The group called for all LEO satellites to be at seventh magnitude or fainter.

    The study authors also note their study is specific to ZTF. Like ZTF, the upcoming Vera C. Rubin Observatory, under construction in Chile, will also survey the sky nightly, but due to its more sensitive imager, astronomers predict that it may be more negatively affected by satellite streaks than ZTF.

    Other authors of the study include Richard Dekany (BS ’89), Matthew Graham, Steven Groom, and Frank Masci of Caltech; Dmitry Duev, a former Caltech postdoc now at Weights & Biases Inc.; Angel Otarola of The European Southern Observatory [Observatoire européen austral][Europaiche Sûdsternwarte] (EU)(CL); and Michael S. Medford of The University of California-Berkeley (US) and DOE’s Lawrence Berkeley National Laboratory (US).

    ZTF is funded by The National Science Foundation(US) and an international collaboration of partners. Additional support comes from The Heising-Simons Foundation (US) and Caltech. ZTF data are processed and archived by Caltech NASA Infrared Science Archive IPAC. NASA supports ZTF’s search for near-Earth objects through the Near-Earth Object Observations program.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Caltech campus

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

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

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

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

    Research

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

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

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

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

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

     
  • richardmitnick 2:14 pm on July 23, 2020 Permalink | Reply
    Tags: "Spectacular ultraviolet flash may finally explain how white dwarfs explode", , , , , For just the second time ever astrophysicists have spotted a spectacular flash of ultraviolet (UV) light accompanying a white dwarf explosion., , Perlmutter Riess and Schmidt proved the accelerating expansion of the universe using Type 1A supernovae., Saul Perlmutter [The Supernova Cosmology Project] Adam Riess and Brian Schmidt [The High-z Supernova Search Team] shared the 2011 Nobel Prize in Physics., SN2019yvq, , , ZTF-Zwicky Transient Facility   

    From Northwestern University: “Spectacular ultraviolet flash may finally explain how white dwarfs explode” 

    Northwestern U bloc
    From Northwestern University

    July 23, 2020

    Amanda Morris
    (847) 467-6790
    amandamo@northwestern.edu

    White dwarf explosion caused extremely rare burst of ultraviolet (UV) light.
    This is just the second time a UV flash accompanied a type Ia supernova.
    White dwarfs are cool objects; UV light requires something incredibly hot.
    Researchers will have a better understanding of how white dwarfs explode as they continue to watch the event throughout the year.

    For just the second time ever, astrophysicists have spotted a spectacular flash of ultraviolet (UV) light accompanying a white dwarf explosion.

    An extremely rare type of supernova, the event is poised to offer insights into several long-standing mysteries, including what causes white dwarfs to explode, how dark energy accelerates the cosmos and how the universe creates heavy metals, such as iron.

    “The UV flash is telling us something very specific about how this white dwarf exploded,” said Northwestern University astrophysicist Adam Miller, who led the research. “As time passes, the exploded material moves farther away from the source. As that material thins, we can see deeper and deeper. After a year, the material will be so thin that we will see all the way into the center of the explosion.”

    At that point, Miller said, his team will know more about how this white dwarf — and all white dwarfs, which are dense remnants of dead stars — explode.

    1
    Zwicky Transient Facility composite image of SN2019yvq (blue dot in the center of the image) in the host galaxy NGC 4441 (large yellow galaxy in the center of the image), which is nearly 140 million light-years away from Earth. SN 2019yvq exhibited a rarely observed ultraviolet flash in the days after the star exploded.
    Credit: ZTF/A. A. Miller (Northwestern University) and D. Goldstein (Caltech)

    Zwicky Transient Facility (ZTF) instrument installed on the 1.2m diameter Samuel Oschin Telescope at Palomar Observatory in California. Courtesy Caltech Optical Observatories

    Caltech Palomar Samuel Oschin 48 inch Telescope, located in San Diego County, California, United States, altitude 1,712 m (5,617 ft)

    The paper was published today (July 23) in The Astrophysical Journal.

    Common event with a rare twist

    Using the Zwicky Transient Facility [above] in California, researchers first spotted the peculiar supernova in December 2019 — just a day after it exploded. The event, dubbed SN2019yvq, occurred in a relatively nearby galaxy located 140 million light-years from Earth, very close to tail of the dragon-shaped Draco constellation.

    Within hours, astrophysicists used NASA’s Neil Gehrels Swift Observatory to study the phenomenon in ultraviolet and X-ray wavelengths.

    NASA Neil Gehrels Swift Observatory

    They immediately classified SN2019yvq as a type Ia (pronounced “one-A”) supernova, a fairly frequent event that occurs when a white dwarf explodes.

    “These are some of the most common explosions in the universe,” Miller said. “But what’s special is this UV flash. Astronomers have searched for this for years and never found it. To our knowledge, this is actually only the second time a UV flash has been seen with a type Ia supernova.”

    Heated mystery

    The rare flash, which lasted for a couple days, indicates that something inside or nearby the white dwarf was incredibly hot. Because white dwarfs become cooler and cooler as they age, the influx of heat puzzled astronomers.

    “The simplest way to create UV light is to have something that’s very, very hot,” Miller said. “We need something that is much hotter than our sun — a factor of three or four times hotter. Most supernovae are not that hot, so you don’t get the very intense UV radiation. Something unusual happened with this supernova to create a very hot phenomenon.”

    Miller and his team believe this is an important clue to understanding why white dwarfs explode, which has been a long-standing mystery in the field. Currently, there are multiple competing hypotheses. Miller is particularly interested in exploring four different hypotheses, which match his team’s data analysis from SN2019yvq.

    Potential scenarios that could cause a white dwarf to explode with a UV flash are:

    A white dwarf consumes material from its companion star and becomes so massive and unstable that it explodes. The white dwarf’s expelled material and the companion star collide, causing a flash of UV emission;
    Extremely hot radioactive material in the white dwarf’s core mixes with its outer layers, causing the outer shell to reach higher temperatures than usual;
    An outer layer of helium ignites carbon within the white dwarf, causing an extremely hot double explosion and a UV flash;
    Two white dwarfs merge, triggering an explosion with colliding ejecta that emit UV radiation.

    “Within a year,” Miller said, “we’ll be able to figure out which one of these four is the most likely explanation.”

    Earth-shattering insights

    Once the researchers know what caused the explosion, they will apply those findings to learn more about planet formation and dark energy.

    Because most of the iron in the universe is created by type Ia supernovae, better understanding this phenomenon could tell us more about our own planet. Iron from exploded stars, for example, formed the core of all rocky planets, including Earth.

    “If you want to understand how the Earth formed, you need to understand where iron came from and how much iron was needed,” Miller said. “Understanding the ways in which a white dwarf explodes gives us a more precise understanding of how iron is created and distributed throughout the universe.”

    Illuminating dark energy

    White dwarfs already play an enormous role in physicists’ current understanding of dark energy as well. Physicists predict that white dwarfs all have the same brightness when they explode. So type Ia supernovae are considered “standard candles,” allowing astronomers to calculate exactly how far the explosions lie from Earth. Using supernovae to measure distances led to the discovery of dark energy, a finding recognized with the 2011 Nobel Prize in Physics.

    _____________________________________________
    4

    4 October 2011

    The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2011

    with one half to

    Saul Perlmutter
    The Supernova Cosmology Project
    Lawrence Berkeley National Laboratory and University of California,
    Berkeley, CA, USA

    and the other half jointly to

    Brian P. Schmidt
    The High-z Supernova Search Team
    Australian National University,
    Weston Creek, Australia

    and

    Adam G. Riess
    The High-z Supernova Search Team
    Johns Hopkins University and Space Telescope Science Institute,
    Baltimore, MD, USA

    “for the discovery of the accelerating expansion of the Universe through observations of distant supernovae”

    Saul Perlmutter [The Supernova Cosmology Project] shared the 2006 Shaw Prize in Astronomy, the 2011 Nobel Prize in Physics, and the 2015 Breakthrough Prize in Fundamental Physics with Brian P. Schmidt and Adam Riess [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

    Written in the stars

    “Some say the world will end in fire, some say in ice…” *
    What will be the final destiny of the Universe? Probably it will end in ice, if we are to believe this year’s Nobel Laureates in Physics. They have studied several dozen exploding stars, called supernovae, and discovered that the Universe is expanding at an ever-accelerating rate. The discovery came as a complete surprise even to the Laureates themselves.

    In 1998, cosmology was shaken at its foundations as two research teams presented their findings. Headed by Saul Perlmutter [The Supernova Cosmology Project], one of the teams had set to work in 1988. Brian Schmidt headed another team [The High-z Supernova Search Team], launched at the end of 1994, where Adam Riess was to play a crucial role.

    The research teams raced to map the Universe by locating the most distant supernovae. More sophisticated telescopes on the ground and in space, as well as more powerful computers and new digital imaging sensors (CCD, Nobel Prize in Physics in 2009), opened the possibility in the 1990s to add more pieces to the cosmological puzzle.

    The teams used a particular kind of supernova, called type Ia supernova. It is an explosion of an old compact star that is as heavy as the Sun but as small as the Earth. A single such supernova can emit as much light as a whole galaxy. All in all, the two research teams found over 50 distant supernovae whose light was weaker than expected – this was a sign that the expansion of the Universe was accelerating. The potential pitfalls had been numerous, and the scientists found reassurance in the fact that both groups had reached the same astonishing conclusion.

    For almost a century, the Universe has been known to be expanding as a consequence of the Big Bang about 14 billion years ago. However, the discovery that this expansion is accelerating is astounding. If the expansion will continue to speed up the Universe will end in ice.

    The acceleration is thought to be driven by dark energy, but what that dark energy is remains an enigma – perhaps the greatest in physics today. What is known is that dark energy constitutes about three quarters of the Universe. Therefore the findings of the 2011 Nobel Laureates in Physics have helped to unveil a Universe that to a large extent is unknown to science. And everything is possible again.
    _____________________________________________

    Standard Candles to measure age and distance of the universe from supernovae. NASA

    5
    Evolution of the ultraviolet and visible light emitted from SN2019yvq. Most Type Ia SNe emit far more light in the visible region of the electromagnetic spectrum than in the ultraviolet. As shown here, SN 2019yvq exhibited a spectacular ultraviolet flash just after it exploded. Credit: A. A. Miller/Northwestern University

    “We don’t have a direct way to measure the distance to other galaxies,” Miller explained. “Most galaxies are actually moving away from us. If there is a type Ia supernova in a distant galaxy, we can use it to measure a combination of distance and velocity that allows us to determine the acceleration of the universe. Dark energy remains a mystery. But these supernovae are the best way to probe dark energy and understand what it is.”

    And by better understanding white dwarfs, Miller believes we potentially could better understand dark energy and how fast it causes the universe to accelerate.

    “At the moment, when measuring distances, we treat all of these explosions as the same, yet we have good reason to believe that there are multiple explosion mechanisms,” he said. “If we can determine the exact explosion mechanism, we think we can better separate the supernovae and make more precise distance measurements.”

    The paper, “The spectacular ultraviolet flash from the peculiar type Ia supernova 2019yvq,” was partially supported by the Large Synoptic Survey Telescope Corporation, the Brinson Foundation and the Moore Foundation.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Northwestern South Campus
    South Campus

    Northwestern is recognized nationally and internationally for its educational programs.

    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.

     
  • richardmitnick 5:12 pm on June 25, 2020 Permalink | Reply
    Tags: "Black Hole Collision May Have Exploded with Light", , , , , , , , ZTF-Zwicky Transient Facility   

    From Caltech: “Black Hole Collision May Have Exploded with Light” 

    Caltech Logo

    From Caltech

    June 25, 2020
    Whitney Clavin
    (626) 395‑1944
    wclavin@caltech.edu

    1
    Artist’s concept of a supermassive black hole and its surrounding disk of gas. Embedded within this disk are two smaller black holes orbiting one another. Using data from the Zwicky Transient Facility (ZTF) at Palomar Observatory, researchers have identified a flare of light suspected to have come from one such binary pair soon after they merged into a larger black hole. The merger of the black holes would have caused them to move in one direction within the disk, plowing through the gas in such a way to create a light flare. The finding, while not confirmed, could amount to the first time that light has been seen from a coalescing pair of black holes. These merging black holes were first spotted on May 21, 2019, by the National Science Foundation’s Laser Interferometer Gravitational-wave Observatory (LIGO) and the European Virgo detector, which picked up gravitational waves generated by the merger.
    Credit: Caltech/R. Hurt (IPAC)

    Zwicky Transient Facility (ZTF) instrument installed on the 1.2m diameter Samuel Oschin Telescope at Palomar Observatory in California. Courtesy Caltech Optical Observatories

    Caltech Palomar Samuel Oschin 48 inch Telescope, located in San Diego County, California, United States, altitude 1,712 m (5,617 ft)

    Possible light flare observed from small black holes within the disk of a massive black hole.

    When two black holes spiral around each other and ultimately collide, they send out ripples in space and time called gravitational waves. Because black holes do not give off light, these events are not expected to shine with any light waves, or electromagnetic radiation. But some theorists have come up with ways in which a black hole merger might explode with light. Now, for the first time, astronomers have seen evidence for one of these light-producing scenarios.

    With the help of Caltech’s Zwicky Transient Facility (ZTF), funded by the National Science Foundation (NSF) and located at Palomar Observatory near San Diego, the scientists have spotted what might be a flare of light from a pair of coalescing black holes. The black hole merger was first witnessed by the NSF’s Laser Interferometer Gravitational-wave Observatory (LIGO) and the European Virgo detector on May 21, 2019, in an event called S190521g. As the black holes merged, jiggling space and time, they sent out gravitational waves.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    While this was happening, ZTF was performing its robotic survey of the sky that captured all kinds of objects that flare, erupt, or otherwise vary in the night sky. One flare the survey caught, generated by a distant active supermassive black hole, or quasar, called J1249+3449, was pinpointed to the region of the gravitational-wave event S190521g.

    “This supermassive black hole was burbling along for years before this more abrupt flare,” says Matthew Graham, a research professor of astronomy at Caltech and the project scientist for ZTF. “The flare occurred on the right timescale, and in the right location, to be coincident with the gravitational-wave event. In our study, we conclude that the flare is likely the result of a black hole merger, but we cannot completely rule out other possibilities.” Graham is lead author of the new study, published today, June 25, in the journal Physical Review Letters.

    “ZTF was specifically designed to identify new, rare, and variable types of astronomical activity like this,” says NSF Division of Astronomical Science Director Ralph Gaume. “NSF support of new technology continues to expand how we can track such events.”

    How do two merging black holes erupt with light? In the scenario outlined by Graham and his colleagues, two partner black holes were nestled within a disk surrounding a much larger black hole.

    “At the center of most galaxies lurks a supermassive black hole. It’s surrounded by a swarm of stars and dead stars, including black holes,” says co-author K. E. Saavik Ford of the City University of New York (CUNY) Graduate Center, the Borough of Manhattan Community College (BMCC), and the American Museum of Natural History (AMNH). “These objects swarm like angry bees around the monstrous queen bee at the center. They can briefly find gravitational partners and pair up but usually lose their partners quickly to the mad dance. But in a supermassive black hole’s disk, the flowing gas converts the mosh pit of the swarm to a classical minuet, organizing the black holes so they can pair up,” she says.

    Once the black holes merge, the new, now-larger black hole experiences a kick that sends it off in a random direction, and it plows through the gas in the disk. “It is the reaction of the gas to this speeding bullet that creates a bright flare, visible with telescopes,” says co-author Barry McKernan, also of the CUNY Graduate Center, BMCC, and AMNH.

    Such a flare is predicted to begin days to weeks after the initial splash of gravitational waves produced during the merger. In this case, ZTF did not catch the event right away, but when the scientists went back and looked through archival ZTF images months later, they found a signal that started days after the May 2019 gravitational-wave event. ZTF observed the flare slowly fade over the period of a month.

    The scientists attempted to get a more detailed look at the light of the supermassive black hole, called a spectrum, but by the time they looked, the flare had already faded. A spectrum would have offered more support for the idea that the flare came from merging black holes within the disk of the supermassive black hole. However, the researchers say they were able to largely rule out other possible causes for the observed flare, including a supernova or a tidal disruption event, which occurs when a black hole essentially eats a star.

    What is more, the team says it is not likely that the flare came from the usual rumblings of the supermassive black hole, which regularly feeds off its surrounding disk. Using the Catalina Real-Time Transient Survey, led by Caltech, they were able to assess the behavior of the black hole over the past 15 years, and found that its activity was relatively normal until May of 2019, when it suddenly intensified.

    “Supermassive black holes like this one have flares all the time. They are not quiet objects, but the timing, size, and location of this flare was spectacular,” says co-author Mansi Kasliwal (MS ’07, PhD ’11), an assistant professor of astronomy at Caltech. “The reason looking for flares like this is so important is that it helps enormously with astrophysics and cosmology questions. If we can do this again and detect light from the mergers of other black holes, then we can nail down the homes of these black holes and learn more about their origins.”

    The newly formed black hole should cause another flare in the next few years. The process of merging gave the object a kick that should cause it to enter the supermassive black hole’s disk again, producing another flash of light that ZTF should be able to see.

    The Physical Review Letters paper was funded by the NSF, NASA, the Heising-Simons Foundation, and the GROWTH (Global Relay of Observatories Watching Transients Happen) program. Other co-authors include: K. Burdge, S.G. Djorgovski, A.J. Drake, D. Duev, A.A. Mahabal, J. Belecki, R. Burruss, G. Helou, S.R. Kulkarni, F.J. Masci, T. Prince, D. Reiley, H. Rodriguez, B. Rusholme, R.M. Smith, all from Caltech; N.P. Ross of the University of Edinburgh; Daniel Stern of the Jet Propulsion Laboratory, managed by Caltech for NASA; M. Coughlin of the University of Minnesota; S. van Velzen of University of Maryland, College Park and New York University; E.C. Bellm of the University of Washington; S.B. Cenko of NASA Goddard Space Flight Center; V. Cunningham of University of Maryland, College Park; and M.T. Soumagnac of the Lawrence Berkeley National Laboratory and the Weizmann Institute of Science.

    In addition to the NSF, ZTF is funded by an international collaboration of partners, with additional support from NASA, the Heising-Simons Foundation, members of the Space Innovation Council at Caltech, and Caltech itself.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 10:23 am on January 16, 2020 Permalink | Reply
    Tags: "First Asteroid Found Inside Orbit of Venus", 2020 AV2 belongs to a small class of asteroids known as Atiras., , it is the first "Vatira" asteroid with the "V" standing for Venus, The Palomar Observatory's 48-inch Samuel Oschin Telescope., ZTF-Zwicky Transient Facility   

    From Caltech: “First Asteroid Found Inside Orbit of Venus” 

    Caltech Logo

    From Caltech

    January 15, 2020

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

    3
    2020 AV2 orbits entirely within the orbit of Venus. Credit: Bryce Bolin/Caltech

    Zwicky Transient Facility (ZTF) instrument installed on the 1.2m diameter Samuel Oschin Telescope at Palomar Observatory in California. Courtesy Caltech Optical Observatories

    1
    ZTF is installed at the Palomar Observatory’s 48-inch Samuel Oschin Telescope. Credit: Palomar/Caltech

    A rare asteroid orbiting snugly within the inner confines of our solar system has been discovered by Caltech’s Zwicky Transient Facility, or ZTF, a survey camera based at Palomar Observatory. The newfound body, named 2020 AV2, is the first asteroid found to orbit entirely within the orbit of Venus.

    “Getting past the orbit of Venus must have been challenging,” says George Helou, executive director of the IPAC astronomy center at Caltech and a ZTF co-investigator, who explains that the asteroid must have migrated in toward Venus from farther out in the solar system. “The only the way it will ever get out of its orbit is if it gets flung out via a gravitational encounter with Mercury or Venus, but more likely it will end up crashing on one of those two planets.”

    2020 AV2 belongs to a small class of asteroids known as Atiras, which are bodies with orbits that fall within the orbit of Earth. More specifically, it is the first “Vatira” asteroid, with the “V” standing for Venus. Vatira asteroids, which were only hypothesized until now, have orbits that fall entirely inside the orbit of Venus.

    The ZTF camera is particularly adept at finding asteroids because it scans the entire sky rapidly and thus can catch the asteroids during their short-lived appearances in the night sky. Because Vatiras orbit so close to our sun, they are only visible at dusk or dawn.

    2020 AV2 is the third Atira discovered by ZTF as part of its Twilight program developed by Wing-Huen Ip of the National Central University in Taiwan, and Quanzhi Ye, formerly of Caltech and now at the University of Maryland. The asteroid, which was initially designated ZTF09k5, was first flagged as a candidate on January 4, 2020, by Bryce Bolin, a postdoctoral scholar at Caltech. Soon thereafter, an alert was posted by the Minor Planet Center, the official organization for cataloging small solar system bodies such as asteroids, and this piqued the interest of the astronomical community. Several telescopes around the globe followed up on the target, helping to pin down the body’s unusual orbit and narrow down estimates of its size.

    The asteroid spans about 1 to 3 kilometers and has an elongated orbit tilted about 15 degrees relative to the plane of our solar system. During its 151-day orbit around the sun, it always travels interior to Venus, but at its closest approach to the sun, it comes very close to the orbit of Mercury.

    “An encounter with a planet probably flung the asteroid into Venus’s orbit,” explains Tom Prince, the Ira S. Bowen Professor of Physics at Caltech and a senior research scientist at JPL, which Caltech manages for NASA, as well as a co-investigator of ZTF. “It’s the opposite of what happens when a space mission swings by a planet for a gravity boost. Instead of gaining energy from a planet, it loses it.”

    Members of the ZTF team says they look forward to hunting for more Vatira asteroids in the future. “We have no idea how many more there are like this or if it’s unique,” says Helou.

    ZTF is funded by the National Science Foundation and an international collaboration of partners. Additional support comes from Caltech and the Heising-Simons Foundation. ZTF data are processed and archived by IPAC. NASA supports ZTF’s search for near-Earth objects through the Near-Earth Object Observations program.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

    Caltech campus

     
  • richardmitnick 7:37 am on October 30, 2019 Permalink | Reply
    Tags: "NSF invests in cyberinfrastructure institute to harness cosmic data", Cyberinfrastructure, , SCIMMA-Scalable Cyberinfrastructure Institute for Multi-Messenger Astrophysics, , ZTF-Zwicky Transient Facility   

    From University of Washington: “NSF invests in cyberinfrastructure institute to harness cosmic data” 

    U Washington

    From University of Washington

    The National Science Foundation awarded the University of Wisconsin-Milwaukee and nine collaborating organizations, including the University of Washington, $2.8 million for a two-year “conceptualization phase” of the Scalable Cyberinfrastructure Institute for Multi-Messenger Astrophysics.

    1
    The night sky at Palouse Falls in southeastern Washington.Mark Stone/University of Washington

    SCIMMA’s goal is to develop algorithms, databases and computing and networking cyberinfrastructure to help scientists interpret multi-messenger observations. Multi-messenger astrophysics combines observations of light, gravitational waves and particles to understand some of the most extreme events in the universe. For example, the observation of both gravitational waves and light from the collision of two neutron stars in 2017 helped explain the origin of heavy elements, allowed an independent measurement of the expansion of the universe and confirmed the association between neutron-star mergers and gamma-ray bursts.

    The institute would facilitate global collaborations, thus transcending the capabilities of any single existing institution or team. It is directed by Patrick Brady, a professor of physics at the University of Wisconsin-Milwaukee and director of the Center for Gravitation, Cosmology and Astrophysics. One of three co-principal investigators on the project is Mario Jurić, a UW associate professor of astronomy and senior data science fellow at the UW eScience Institute.

    As part of SCIMMA, UW researchers will work to develop a “transient alert” system that will alert researchers around the world about cosmic events picked up, for example, by astronomical observatories.

    “These events could include phenomena like collisions between black holes and neutron stars detected via gravitational waves, exploding supernovae detected by neutrino emissions, and other energetic phenomena detected in visible wavelengths of light,” said Jurić, who is also a faculty member with the UW DIRAC Institute. “UW researchers have demonstrated these technologies as part of the Zwicky Transient Facility project, where the UW-built ZTF Alert Distribution System transmitted more than 100 million alerts over the past two years.”

    Zwicky Transient Facility (ZTF) instrument installed on the 1.2m diameter Samuel Oschin Telescope at Palomar Observatory in California. Courtesy Caltech Optical Observatories

    Caltech Palomar Samuel Oschin 48 inch Telescope, located in San Diego County, California, United States, altitude 1,712 m (5,617 ft)

    W researchers will also help develop a prototype remote analysis platform, which will allow scientists to analyze archived multi-messenger astrophysics using future resources provided by SCIMMA, said Jurić.

    SCIMMA’s two-year conceptualization phase began Sept. 1. Among its goals are enabling seamless co-analysis of disparate datasets by supporting the interoperability of software and data services. In addition, over the next two years SCIMMA will develop education and training curricula designed to enhance the STEM workforce, according to an announcement by the NSF.

    “Multi-messenger astrophysics is a data-intensive science in its infancy that is already transforming our understanding of the universe,” said Brady. “The promise of multi-messenger astrophysics, however, can be realized only if sufficient cyberinfrastructure is available to rapidly handle, combine and analyze the very large-scale distributed data from all types of astronomical measurements. The conceptualization phase of SCIMMA will balance rapid prototyping, novel algorithm development and software sustainability to accelerate scientific discovery over the next decade and more.”

    Additional project collaborators include Columbia University; the Center for Advanced Computing and Department of Astronomy at Cornell University; Las Cumbres Observatory, a California-based network of observatories; Michigan State University; Pennsylvania State University; the University of California, Santa Barbara; the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; and the Texas Advanced Computing Center at the University of Texas at Austin.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    u-washington-campus
    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
    So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 1:46 pm on September 18, 2019 Permalink | Reply
    Tags: , , , Caltech Palomar Samuel Oschin 48 inch Telescope, , , LINER galaxies-low ionization nuclear emission line region galaxies, , ZTF-Zwicky Transient Facility   

    From University of Maryland: “UMD-led Study Captures Six Galaxies Undergoing Sudden, Dramatic Transitions” 

    From University of Maryland

    September 18, 2019

    Matthew Wright
    301-405-9267
    mewright@umd.edu

    Zwicky Transient Facility observations reveal surprising transformations from sleepy LINER galaxies to blazing quasars within months.

    Zwicky Transient Facility (ZTF) instrument installed on the 1.2m diameter Samuel Oschin Telescope at Palomar Observatory in California. Courtesy Caltech Optical Observatories

    Edwin Hubble at Caltech Palomar Samuel Oschin 48 inch Telescope, (credit: Emilio Segre Visual Archives/AIP/SPL)

    Caltech Palomar Samuel Oschin 48 inch Telescope, located in San Diego County, California, United States, altitude 1,712 m (5,617 ft)

    1
    A new study led by University of Maryland astronomers documented six sleepy, low-ionization nuclear emission-line region galaxies (LINERs; left) suddenly transforming into blazing quasars (right), home to the brightest of all active galactic nuclei. The researchers suggest they have discovered an entirely new type of black hole activity at the centers of these six LINER galaxies. Image credits: (Left; infrared & visible light imagery): ESA/Hubble, NASA and S. Smartt (Queen’s University Belfast); (Right; artist’s concept): NASA/JPL-Caltech

    Galaxies come in a wide variety of shapes, sizes and brightnesses, ranging from humdrum ordinary galaxies to luminous active galaxies. While an ordinary galaxy is visible mainly because of the light from its stars, an active galaxy shines brightest at its center, or nucleus, where a supermassive black hole emits a steady blast of bright light as it voraciously consumes nearby gas and dust.

    Sitting somewhere on the spectrum between ordinary and active galaxies is another class, known as low-ionization nuclear emission-line region (LINER) galaxies. While LINERs are relatively common, accounting for roughly one-third of all nearby galaxies, astronomers have fiercely debated the main source of light emission from LINERs. Some argue that weakly active galactic nuclei are responsible, while others maintain that star-forming regions outside the galactic nucleus produce the most light.

    A team of astronomers observed six mild-mannered LINER galaxies suddenly and surprisingly transforming into ravenous quasars—home to the brightest of all active galactic nuclei. The team reported their observations, which could help demystify the nature of both LINERs and quasars while answering some burning questions about galactic evolution, in The Astrophysical Journal on September 18, 2019. Based on their analysis, the researchers suggest they have discovered an entirely new type of black hole activity at the centers of these six LINER galaxies.

    “For one of the six objects, we first thought we had observed a tidal disruption event, which happens when a star passes too close to a supermassive black hole and gets shredded,” said Sara Frederick, a graduate student in the University of Maryland Department of Astronomy and the lead author of the research paper. “But we later found it was a previously dormant black hole undergoing a transition that astronomers call a ‘changing look,’ resulting in a bright quasar. Observing six of these transitions, all in relatively quiet LINER galaxies, suggests that we’ve identified a totally new class of active galactic nucleus.”

    All six of the surprising transitions were observed during the first nine months of the Zwicky Transient Facility (ZTF), an automated sky survey project based at Caltech’s Palomar Observatory near San Diego, California, which began observations in March 2018. UMD is a partner in the ZTF effort, facilitated by the Joint Space-Science Institute (JSI), a partnership between UMD and NASA’s Goddard Space Flight Center.

    Changing look transitions have been documented in other galaxies—most commonly in a class of active galaxies known as Seyfert galaxies. By definition, Seyfert galaxies all have a bright, active galactic nucleus, but Type 1 and Type 2 Seyfert galaxies differ in the amount of light they emit at specific wavelengths. According to Frederick, many astronomers suspect that the difference results from the angle at which astronomers view the galaxies.

    Type 1 Seyfert galaxies are thought to face Earth head-on, giving an unobstructed view of their nuclei, while Type 2 Seyfert galaxies are tilted at an oblique angle, such that their nuclei are partially obscured by a donut-shaped ring of dense, dusty gas clouds. Thus, changing look transitions between these two classes present a puzzle for astronomers, since a galaxy’s orientation towards Earth is not expected to change.

    Frederick and her colleagues’ new observations may call these assumptions into question.

    “We started out trying to understand changing look transformations in Seyfert galaxies. But instead, we found a whole new class of active galactic nucleus capable of transforming a wimpy galaxy to a luminous quasar,” said Suvi Gezari, an associate professor of astronomy at UMD, a co-director of JSI and a co-author of the research paper. “Theory suggests that a quasar should take thousands of years to turn on, but these observations suggest that it can happen very quickly. It tells us that the theory is all wrong. We thought that Seyfert transformation was the major puzzle. But now we have a bigger issue to solve.”

    Frederick and her colleagues want to understand how a previously quiet galaxy with a calm nucleus can suddenly transition to a bright beacon of galactic radiation. To learn more, they performed follow-up observations on the objects with the Discovery Channel Telescope, which is operated by the Lowell Observatory in partnership with UMD, Boston University, the University of Toledo and Northern Arizona University.


    Discovery Channel Telescope, operated by the Lowell Observatory in partnership with UMD, Boston University, the University of Toledo and Northern Arizona University, at Lowell Observatory, Happy Jack AZ, USA, Altitude 2,360 m (7,740 ft)

    These observations helped to clarify aspects of the transitions, including how the rapidly transforming galactic nuclei interacted with their host galaxies.

    “Our findings confirm that LINERs can, in fact, host active supermassive black holes at their centers,” Frederick said. “But these six transitions were so sudden and dramatic, it tells us that there is something altogether different going on in these galaxies. We want to know how such massive amounts of gas and dust can suddenly start falling into a black hole. Because we caught these transitions in the act, it opens up a lot of opportunities to compare what the nuclei looked like before and after the transformation.”

    Unlike most quasars, which light up the surrounding clouds of gas and dust far beyond the galactic nucleus, the researchers found that only the gas and dust closest to the nucleus had been turned on. Frederick, Gezari and their collaborators suspect that this activity gradually spreads from the galactic nucleus—and may provide the opportunity to map the development of a newborn quasar.

    “It’s surprising that any galaxy can change its look on human time scales. These changes are taking place much more quickly than we can explain with current quasar theory,” Frederick said. “It will take some work to understand what can disrupt a galaxy’s accretion structure and cause these changes on such short order. The forces at play must be very extreme and very dramatic.”

    ###

    In addition to Frederick and Gezari, UMD-affiliated co-authors of the research paper include Adjunct Associate Professor of Astronomy Bradley Cenko, former Neil Gehrels Prize Postdoctoral Fellow Erin Kara and astronomy graduate student Charlotte Ward.

    “A New Class of Changing-look LINERs,” by Sara Frederick, Suvi Gezari, Matthew Graham, Bradley Cenko, Sjoert Van Velzen, Daniel Stern, Nadejda Blagorodnova, Shrinivas Kulkarni, Lin Yan, Kishalay De, Christoffer Fremling, Tiara Hung, Erin Kara, David Shupe, Charlotte Ward, Eric Bellm, Richard Dekany, Dmitry Duev, Ulrich Feindt, Matteo Giomi, Thomas Kupfer, Russ Laher, Frank Masci, Adam Miller, James Neill, Chow-Choong Ngeow, Maria Patterson, Michael Porter, Ben Rusholme, Jesper Sollerman and Richard Walters, was published in The Astrophysical Journal on September 18, 2019.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Maryland Campus

    Driven by the pursuit of excellence, the University of Maryland has enjoyed a remarkable rise in accomplishment and reputation over the past two decades. By any measure, Maryland is now one of the nation’s preeminent public research universities and on a path to become one of the world’s best. To fulfill this promise, we must capitalize on our momentum, fully exploit our competitive advantages, and pursue ambitious goals with great discipline and entrepreneurial spirit. This promise is within reach. This strategic plan is our working agenda.

    The plan is comprehensive, bold, and action oriented. It sets forth a vision of the University as an institution unmatched in its capacity to attract talent, address the most important issues of our time, and produce the leaders of tomorrow. The plan will guide the investment of our human and material resources as we strengthen our undergraduate and graduate programs and expand research, outreach and partnerships, become a truly international center, and enhance our surrounding community.

    Our success will benefit Maryland in the near and long term, strengthen the State’s competitive capacity in a challenging and changing environment and enrich the economic, social and cultural life of the region. We will be a catalyst for progress, the State’s most valuable asset, and an indispensable contributor to the nation’s well-being. Achieving the goals of Transforming Maryland requires broad-based and sustained support from our extended community. We ask our stakeholders to join with us to make the University an institution of world-class quality with world-wide reach and unparalleled impact as it serves the people and the state of Maryland.

     
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