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  • richardmitnick 9:02 am on February 14, 2018 Permalink | Reply
    Tags: , , , , , , , , Supermassive Black Holes   

    From ALMA: “ALMA Observes a Rotating Dust and Gas Donut around a Supermassive Black Hole” 

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ALMA

    14 February, 2018

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Masaaki Hiramatsu
    Education and Public Outreach Officer, NAOJ Chile
    Observatory
, Tokyo – Japan
    Phone: +81 422 34 3630
    Email: hiramatsu.masaaki@nao.ac.jp

    Charles E. Blue
    Public Information Officer
    National Radio Astronomy Observatory Charlottesville, Virginia – USA
    Phone: +1 434 296 0314
    Cell phone: +1 202 236 6324
    Email: cblue@nrao.edu

    Richard Hook
    Public Information Officer, ESO
    Garching bei München, Germany
    Phone: +49 89 3200 6655
    Cell phone: +49 151 1537 3591
    Email: rhook@eso.org

    1
    Artist’s impression of the dusty gaseous torus around an active supermassive black hole. ALMA revealed the rotation of the torus very clearly for the first time. Credit: ALMA (ESO/NAOJ/NRAO)

    High resolution observations with the Atacama Large Millimeter/submillimeter Array (ALMA) imaged a rotating dusty gas torus around an active supermassive black hole. The existence of such rotating donuts-shape structures was first suggested decades ago, but this is the first time one has been confirmed so clearly. This is an important step in understanding the co-evolution of supermassive black holes and their host galaxies.

    2
    The central region of the spiral galaxy M77. The NASA/ESA Hubble Space Telescope imaged the distribution of stars. ALMA revealed the distribution of gas in the very center of the galaxy. ALMA imaged a horseshoe-like structure with a radius of 700 light-years and a central compact component with a radius of 20 light-years. The latter is the gaseous torus around the AGN. Red indicates emission from formyl ions (HCO+) and green indicates hydrogen cyanide emission. Credit: ALMA (ESO/NAOJ/NRAO), Imanishi et al., NASA/ESA Hubble Space Telescope and A. van der Hoeven

    NASA/ESA Hubble Telescope

    Almost all galaxies hold concealed monstrous black holes in their centers. Researchers have known for a long time that the more massive the galaxy is, the more massive the central black hole is. This sounds reasonable at first, but host galaxies are 10 billion times bigger than the central black holes; it should be difficult for two objects of such vastly different scales to directly affect each other. So how could such a relation develop?

    Aiming to solve this shadowy problem, a team of astronomers utilized the high resolution of ALMA to observe the center of spiral galaxy M77. The central region of M77 is an “active galactic nucleus,” or AGN, which means that matter is vigorously falling toward the central supermassive black hole and emitting intense light. AGNs can strongly affect the surrounding environment, therefore they are important objects for solving the mystery of the co-evolution of galaxies and black holes.

    The team imaged the area around the supermassive black hole in M77 and resolved a compact gaseous structure with a radius of 20 light-years. And, the astronomers found that the compact structure is rotating around the black hole, as expected.2
    Motion of gas around the supermassive black hole in the center of M77. The gas moving toward us is shown in blue and that moving away from us is in red. The gas’s rotation is centered around the black hole. Credit: ALMA (ESO/NAOJ/NRAO), Imanishi et al.

    “To interpret various observational features of AGNs, astronomers have assumed rotating donut-like structures of dusty gas around active supermassive black holes. This is called the ‘unified model’ of AGN,” explained Masatoshi Imanishi, from the National Astronomical Observatory of Japan (NAOJ), the lead author on a paper published in the Astrophysical Journal Letters. “However, the dusty gaseous donut is very tiny in appearance. With the high resolution of ALMA, now we can directly see the structure.”

    Many astronomers have observed the center of M77 before, but never has the rotation of the gas donut around the black hole been seen so clearly. Besides the superior resolution of ALMA, the selection of molecular emission lines to observe was key to revealing the structure. The team observed specific microwave emission from hydrogen cyanide molecules (HCN) and formyl ions (HCO+). These molecules emit microwaves only in dense gas, whereas the more frequently observed carbon monoxide (CO) emits microwaves under a variety of conditions [1]. The torus around the AGN is assumed to be very dense, and the team’s strategy was right on the mark.

    “Previous observations have revealed the east-west elongation of the dusty gaseous torus. The dynamics revealed from our ALMA data agrees exactly with the expected rotational orientation of the torus,” said Imanishi.

    Interestingly, the distribution of gas around the supermassive black hole is much more complicated than what a simple unified model suggests. The torus seems to have an asymmetry and the rotation is not just following the gravity of the black hole but also contains highly random motion. These facts could indicate the AGN had a violent history, possibly including a merger with a small galaxy [2]. Nevertheless, the identification of the rotating torus is an important step.

    The Milky Way Galaxy, where we live, also has a supermassive black hole at its center.

    Milky Way Galaxy Credits: NASA/JPL-Caltech/R. Hurt

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

    This black hole is, however, in a very quiet state. Only a tiny amount of gas is accreting onto it. Therefore, to investigate an AGN in detail, astronomers need to observe the centers of distant galaxies. M77 is one of the nearest AGN and a suitable object for peering into the very center in detail.

    These observation results were published as Imanishi et al. ALMA Reveals an Inhomogeneous Compact Rotating Dense Molecular Torus at the NGC 1068 Nucleus in the Astrophysical Journal Letters (2018 February 1 issue, 853, L25).

    The research team members are:

    Masatoshi Imanishi (National Astronomical Observatory of Japan/SOKENDAI), Kouichiro Nakanishi (National Astronomical Observatory of Japan/SOKENDAI), Takuma Izumi (National Astronomical Observatory of Japan), and Keiichi Wada (Kagoshima University).

    Notes

    [1] García-Burillo et al. (2016) observed the distribution and motion of CO with ALMA and did not find clear rotation along the east-west torus direction. Their interpretation is that the turbulent motion is so intense that the east-west oriented rotating motion is not clear. Gallimore et al. (2016) also observed CO emission and found gas motion in the north-south direction. They interpret this as outflowing gas from the black hole.

    [2] Recently, astronomers used the Subaru Telescope to observe M77 and revealed signatures of a merger with a small galaxy billions of years ago. For details, please read the press release Minor Merger Kicks Supermassive Black Hole into High Gear issued in October 2017 from the Subaru Telescope.

    See the full article here .

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    The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

    NRAO Small
    ESO 50 Large
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  • richardmitnick 8:45 am on February 8, 2018 Permalink | Reply
    Tags: A New Look at Speeding Outflows, , , , , , , Supermassive Black Holes, UFOs- ultra-fast outflows   

    From AAS NOVA: ” A New Look at Speeding Outflows” 

    AASNOVA

    AAS NOVA

    7 February 2018
    Susanna Kohler

    1
    Artist’s impression of a galaxy that is releasing material via two strongly collimated jets (shown in red/orange) as well as via wide-angle, ultra-fast outflows (shown in gray/blue). The inset shows a closeup of the accretion disk and central supermassive black hole at the galaxy’s core. [ESA/AOES Medialab].

    The compact centers of active galaxies — known as active galactic nuclei, or AGN — are known for the dynamic behavior they exhibit as the supermassive black holes at their centers accrete matter. New observations of outflows from a nearby AGN provide a more detailed look at what happens in these extreme environments.

    Outflows from Giants

    2
    The powerful radio jets of Cygnus A, which extend far beyond the galaxy. [NRAO/AUI].

    AGN consist of a supermassive black hole of millions to tens of billions of solar masses surrounded by an accretion disk of in-falling matter. But not all the material falling toward the black hole accretes! Some of it is flung from the AGN via various types of outflows.

    The most well-known of these outflows are powerful radio jets — collimated and incredibly fast-moving streams of particles that blast their way out of the host galaxy and into space. Only around 10% of AGN are observed to host such jets, however — and there’s another outflow that’s more ubiquitous.

    Fast-Moving Absorbers

    Perhaps 30% of AGN — both those with and without observed radio jets — host wider-angle, highly ionized gaseous outflows known as ultra-fast outflows (UFOs). Ultraviolet and X-ray radiation emitted from the AGN is absorbed by the UFO, revealing the outflow’s presence: absorption lines appear in the ultraviolet and X-ray spectra of the AGN, blue-shifted due to the high speeds of the absorbing gas in the outflow.

    3
    Quasar PG 1211+143, indicated by the crosshairs at the center of the image, in the color context of its surroundings. [SDSS/S. Karge]

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft)

    But what is the nature of UFOs? Are they disk winds? Or are they somehow related to the radio jets? And what impact do they have on the AGN’s host galaxy?

    X-ray and Ultraviolet Cooperation

    New observations are now providing fresh information about one particular UFO. A team of scientists led by Ashkbiz Danehkar (Harvard-Smithsonian Center for Astrophysics [CfA]) recently used the Chandra and Hubble space telescopes to make the first simultaneous observations of the same outflow — a UFO in quasar PG 1211+143 — in both X-rays and in ultraviolet.

    Danehkar and collaborators found absorption lines in both sets of data revealing an outflow moving at ~17,000 km/s (for reference, that’s ~5.6% of the speed of light, and more than 1,500 times faster than Elon Musk’s roadster will be traveling at its maximum speed in the orbit it was launched onto yesterday by the Falcon Heavy). Having the information both from the X-ray and the ultraviolet data provides the opportunity to better asses the UFO’s physical characteristics.

    A Link Between Black Holes and Galaxies?

    4
    The X-ray spectrum for PG 1211+143 was obtained by Chandra HETGS (top); the ultraviolet spectrum was obtained by HST-COS G130M (bottom). [Adapted from Danehkar et al. 2018]

    NASA/Chandra Telescope

    NASA/ESA Hubble Telescope

    The authors use models of the data to demonstrate the plausibility of a scenario in which a shock driven by the radio jet gives rise to the fast bulk outflows detected in the X-ray and ultraviolet spectra.

    They also estimate the impact that the outflows might have on the AGN’s host galaxy, demonstrating that the energy injected into the galaxy could be somewhere between 0.02% and 0.6% of the AGN’s total luminosity. At the higher end of this range, this could have an evolutionary impact on the host galaxy, suggesting a possible link between the black hole’s behavior and how its host galaxy evolves.

    In order to draw definitive conclusions, we will need higher-resolution observations that can determine the total size and extent of these outflows. For that, we may need to wait for 2023, when a proposed X-ray spectrometer that might fit the bill, Arcus, may be launched.

    Citation

    Ashkbiz Danehkar et al 2018 ApJ http://iopscience.iop.org/article/10.3847/1538-4357/aaa427/meta

    See the full article here .

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    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
  • richardmitnick 2:58 pm on January 22, 2018 Permalink | Reply
    Tags: "Cosmic messenger" particles, , , , , , , KM3NeT neutrino telescope, , , Supermassive Black Holes, , ,   

    From Penn State: “Three types of extreme-energy space particles may have unified origin” 

    Penn State Bloc

    Pennsylvania State University

    22 January 2018
    Kohta Murase
    murase@psu.edu
    (+1) 814-863-9594

    Barbara Kennedy (PIO):
    bkk1@psu.edu,
    (+1) 814-863-4682

    [ Barbara K. Kennedy ]

    1
    This image illustrates the “multi-messenger” emission from a gigantic reservoir of cosmic rays that are accelerated by powerful jets from a supermassive black hole. Credit: Kanoko Horio.

    One of the biggest mysteries in astroparticle physics has been the origins of ultrahigh-energy cosmic rays, very high-energy neutrinos, and high-energy gamma rays. Now, a new theoretical model reveals that they all could be shot out into space after cosmic rays are accelerated by powerful jets from supermassive black holes and they travel inside clusters and groups of galaxies. It also shows that these space particles could travel inside clusters and groups of galaxies.

    The model explains the natural origins of all three types of “cosmic messenger” particles simultaneously, and is the first astrophysical model of its kind based on detailed numerical computations. A scientific paper that describes this model, produced by Penn State and University of Maryland scientists, will be published as an Advance Online Publication on the website of the journal Nature Physics on January 22, 2018.

    “Our model shows a way to understand why these three types of cosmic messenger particles have a surprisingly similar amount of power input into the universe, despite the fact that they are observed by space-based and ground-based detectors over ten orders of magnitude in individual particle energy,” said Kohta Murase, assistant professor of physics and astronomy and astrophysics at Penn State. “The fact that the measured intensities of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays are roughly comparable tempted us to wonder if these extremely energetic particles have some physical connections. The new model suggests that very high-energy neutrinos and high-energy gamma rays are naturally produced via particle collisions as daughter particles of cosmic rays, and thus can inherit the comparable energy budget of their parent particles. It demonstrates that the similar energetics of the three cosmic messengers may not be a mere coincidence.”

    Ultrahigh-energy cosmic rays are the most energetic particles in the universe — each of them carries an energy that is too high to be produced even by the Large Hadron Collider, the most powerful particle accelerator in the world. Neutrinos are mysterious and ghostly particles that hardly ever interact with matter. Very high-energy neutrinos, with energy more than one million mega-electronvolts, have been detected in the IceCube neutrino observatory in Antarctica.

    U Wisconsin IceCube neutrino observatory

    U Wisconsin IceCube experiment at the South Pole



    U Wisconsin ICECUBE neutrino detector at the South Pole


    IceCube Gen-2 DeepCore PINGU


    IceCube reveals interesting high-energy neutrino events

    Gamma rays have the highest-known electromagnetic energy — those with energies more than a billion times higher than a photon of visible light have been observed by the Fermi Gamma-ray Space Telescope and other ground-based observatories.

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    “Combining all information on these three types of cosmic messengers is complementary and relevant, and such a multi-messenger approach has become extremely powerful in the recent years,” Murase said.

    Murase and the first author of this new paper, Ke Fang, a postdoctoral associate at the University of Maryland, attempt to explain the latest multi-messenger data from very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays, based on a single but realistic astrophysical setup. They found that the multi-messenger data can be explained well by using numerical simulations to analyze the fate of these charged particles.

    “In our model, cosmic rays accelerated by powerful jets of active galactic nuclei escape through the radio lobes that are often found at the end of the jets,” Fang said. “Then we compute the cosmic-ray propagation and interaction inside galaxy clusters and groups in the presence of their environmental magnetic field. We further simulate the cosmic-ray propagation and interaction in the intergalactic magnetic fields between the source and the Earth. Finally we integrate the contributions from all sources in the universe.”

    The leading suspects in the half-century old mystery of the origin of the highest-energy cosmic particles in the universe were in galaxies called “active galactic nuclei,” which have a super-radiating core region around the central supermassive black hole. Some active galactic nuclei are accompanied by powerful relativistic jets. High-energy cosmic particles that are generated by the jets or their environments are shot out into space almost as fast as the speed of light.

    “Our work demonstrates that the ultrahigh-energy cosmic rays escaping from active galactic nuclei and their environments such as galaxy clusters and groups can explain the ultrahigh-energy cosmic-ray spectrum and composition. It also can account for some of the unexplained phenomena discovered by ground-based experiments,” Fang said. “Simultaneously, the very high-energy neutrino spectrum above one hundred million mega-electronvolts can be explained by particle collisions between cosmic rays and the gas in galaxy clusters and groups. Also, the associated gamma-ray emission coming from the galaxy clusters and intergalactic space matches the unexplained part of the diffuse high-energy gamma-ray background that is not associated with one particular type of active galactic nucleus.”

    “This model paves a way to further attempts to establish a grand-unified model of how all three of these cosmic messengers are physically connected to each other by the same class of astrophysical sources and the common mechanisms of high-energy neutrino and gamma-ray production,” Murase said. “However, there also are other possibilities, and several new mysteries need to be explained, including the neutrino data in the ten-million mega-electronvolt range recorded by the IceCube neutrino observatory in Antarctica. Therefore, further investigations based on multi-messenger approaches — combining theory with all three messenger data — are crucial to test our model.”

    The new model is expected to motivate studies of galaxy clusters and groups, as well as the development of other unified models of high-energy cosmic particles. It is expected to be tested rigorously when observations begin to be made with next-generation neutrino detectors such as IceCube-Gen2 and KM3Net, and the next-generation gamma-ray telescope, Cherenkov Telescope Array.

    Artist’s expression of the KM3NeT neutrino telescope

    HESS Cherenkov Telescope Array, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg

    “The golden era of multi-messenger particle astrophysics started very recently,” Murase said. “Now, all information we can learn from all different types of cosmic messengers is important for revealing new knowledge about the physics of extreme-energy cosmic particles and a deeper understanding about our universe.”

    The research was partially supported by the National Science Foundation (grant No. PHY-1620777) and the Alfred P. Sloan Foundation.

    See the full article here .

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  • richardmitnick 7:01 am on January 11, 2018 Permalink | Reply
    Tags: , , , , , , , Supermassive Black Holes   

    From Futurism: “This Year, We’ll See a Black Hole for the First Time in History” 

    futurism-bloc

    Futurism

    1.10.18
    Kristin Houser

    Using data collected from their network of telescopes, the Event Horizons Telescope team hopes to produce the first ever image of a black hole in 2018.

    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 NOEMA interferometer
    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 Hawaii SAO
    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

    Plateau de Bure interferometer
    Plateau de Bure interferometer

    NSF CfA Greenland telescope

    Greenland Telescope

    First Look At A Black Hole

    Within the next 12 months, astrophysicists believe they’ll be able to do something that’s never been done before, and it could have far-reaching implications for our understanding of the universe. A black hole is a point in space with a gravitational pull so strong that not even light can escape from it. Albert Einstein predicted the existence of black holes in his theory of general relativity, but even he wasn’t convinced that they actually existed. And thus far, no one has been able to produce concrete evidence that they do. The Event Horizon Telescope (EHT) could change that.

    The EHT isn’t so much one telescope as it is a network of telescopes around the globe. By working in harmony, these devices can provide all of the components necessary to capture an image of a black hole.

    “First, you need ultra-high magnification — the equivalent of being able to count the dimples on a golf ball in Los Angeles when you are sitting in New York,” EHT Director Sheperd Doeleman told Futurism.

    Next, said Doeleman, you need a way to see through the gas in the Milky Way and the hot gas surrounding the black hole itself. That requires a telescope as big as the Earth, which is where the EHT comes into play.

    The EHT team created a “virtual Earth-sized telescope,” said Doeleman, using a network of individual radio dishes scattered across the planet. They synchronized the dishes so that they could be programmed to observe the same point in space at the exact same time and record the radio waves they detected onto hard disks.

    The idea was that, by combining this data at a later date, the EHT team could produce an image comparable to one that could have been created using a single Earth-sized telescope.

    In April 2017, the EHT team put their telescope to the test for the first time. Over the course of five nights, eight dishes across the globe set their sights on Sagittarius A* (Sgr A*), a point in the center of the Milky Way that researchers believe is the location of a supermassive black hole.

    Data from the South Pole Telescope didn’t reach the MIT Haystack Observatory until mid-December due to a lack of cargo flights out of the region. Now that the team has the data from all eight radio dishes, they can begin their analysis in the hopes of producing the first image of a black hole.

    Proving Einstein Right (or Wrong)

    Not only would an image of a black hole prove that they do exist, it would also reveal brand new insights into our universe.

    “The impact of black holes on the universe is huge,” said Doeleman. “It’s now believed that the supermassive black holes at the center of galaxies and the galaxies they live in evolve together over cosmic times, so observing what happens near the event horizon will help us understand the universe on larger scales.”

    In the future, researchers could take images of a single black hole over time. This would allow the scientists to determine whether or not Einstein’s theory of general relativity holds true at the black hole boundary, as well as study how black holes grow and absorb matter, said Doeleman.

    See also https://bhi.fas.harvard.edu/ and http://eventhorizontelescope.org/

    See the full article here .

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    Futurism covers the breakthrough technologies and scientific discoveries that will shape humanity’s future. Our mission is to empower our readers and drive the development of these transformative technologies towards maximizing human potential.

     
  • richardmitnick 1:07 pm on January 10, 2018 Permalink | Reply
    Tags: , , , , Direct SMBH mass measurements in galaxies farther away are made using a technique called “reverberation mapping”, farther away, How massive is Supermassive? Astronomers measure more black holes, Key to the success of the SDSS Reverberation Mapping project lies in the SDSS’s ability to study many quasars at once, , Supermassive Black Holes   

    From SDSS: “How massive is Supermassive? Astronomers measure more black holes, farther away” 

    SDSS Telescope at Apache Point Observatory, NM, USA, Altitude 2,788 meters (9,147 ft)


    Sloan Digital Sky Survey

    January 9, 2018
    Today, astronomers from the Sloan Digital Sky Survey (SDSS) announced new measurements of the masses of a large sample of supermassive black holes far beyond the local Universe.

    1
    An artist’s rendering of the inner regions of an active galaxy/quasar, with a supermassive black hole at the center surrounded by a disk of hot material falling in. The inset at the bottom right shows how the brightness of light coming from the two different regions changes with time.
    The top panel of the plot shows the “continuum” region, which originates close in to the black hole (the general vicinity is indicated by the “swoosh” shape). The bottom panel shows the H-beta emission line region, which comes from fast-moving hydrogen gas farther away from the black hole (the general vicinity is indicated by the other “swoosh”). The time span covered by these two light curves is about six months.
    The bottom plot “echoes” the top, with a slight time delay of about 10 days indicated by the vertical line. This means that the distance between these two regions is about 10 light-days (about 150 billion miles, or 240 million kilometers). Image Credit: Nahks Tr’Ehnl (www.nahks.com) and Catherine Grier (The Pennsylvania State University) and the SDSS collaboration

    The results, being presented at the American Astronomical Society (AAS) meeting in National Harbor, Maryland and published in The Astrophysical Journal, represent a major step forward in our ability to measure supermassive black hole masses in large numbers of distant quasars and galaxies.

    “This is the first time that we have directly measured masses for so many supermassive black holes so far away,” says Catherine Grier, a postdoctoral fellow at the Pennsylvania State University and the lead author of this work. “These new measurements, and future measurements like them, will provide vital information for people studying how galaxies grow and evolve throughout cosmic time.”

    Supermassive Black Holes (SMBHs) are found in the centers of nearly every large galaxy, including those in the farthest reaches of the Universe. The gravitational attraction of these supermassive black holes is so great that nearby dust and gas in the host galaxy is inexorably drawn in. The infalling material heats up to such high temperatures that it glows brightly enough to be seen all the way across the Universe. These bright disks of hot gas are known as “quasars,” and they are clear indicators of the presence of supermassive black holes. By studying these quasars, we learn not only about SMBHs, but also about the distant galaxies that they live in. But to do all of this requires measurements of the properties of the SMBHs, most importantly their masses.

    The problem is that measuring the masses of SMBHs is a daunting task. Astronomers measure SMBH masses in nearby galaxies by observing groups of stars and gas near the galaxy center — however, these techniques do not work for more distant galaxies, because they are so far away that telescopes cannot resolve their centers. Direct SMBH mass measurements in galaxies farther away are made using a technique called “reverberation mapping.”

    Reverberation mapping works by comparing the brightness of light coming from gas very close in to the black hole (referred to as the “continuum” light) to the brightness of light coming from fast-moving gas farther out. Changes occurring in the continuum region impact the outer region, but light takes time to travel outwards, or “reverberate.” This reverberation means that there is a time delay between the variations seen in the two regions. By measuring this time delay, astronomers can determine how far out the gas is from the black hole. Knowing that distance allows them to measure the mass of the supermassive black hole — even though they can’t see the details of the black hole itself.

    Over the past 20 years, astronomers have used the reverberation mapping technique to laboriously measure the masses of around 60 SMBHs in nearby active galaxies. Reverberation mapping requires getting observations of these active galaxies, over and over again for several months — and so for the most part, measurements are made for only a handful of active galaxies at a time. Using the reverberation mapping technique on quasars, which are farther away, is even more difficult, requiring years of repeated observations. Because of these observational difficulties, astronomers had only successfully used reverberation mapping to measure SMBH masses for a handful of more distant quasars — until now.

    3
    A graph of known supermassive black hole masses at various “lookback times,” which measures the time into the past we see when we look at each quasar.
    More distant quasars have longer lookback times (since their light takes longer to travel to Earth), so we see them as they appeared in the more distant past. The Universe is about 13.8 billion years old, so the graph goes back to when the Universe was about half of its current age.
    The black hole masses measured in this work are shown as purple circles, while gray squares show black hole masses measured by prior reverberation mapping projects. The sizes of the squares and circles are related to the masses of the black holes they represent. The graph shows black holes from 5 million to 1.7 billion times the mass of the Sun.
    Image Credit: Catherine Grier (The Pennsylvania State University) and the SDSS collaboration

    In this new work, Grier’s team has used an industrial-scale application of the reverberation mapping technique with the goal of measuring black hole masses in tens to hundreds of quasars. The key to the success of the SDSS Reverberation Mapping project lies in the SDSS’s ability to study many quasars at once — the program is currently observing about 850 quasars simultaneously. But even with the SDSS’s powerful telescope, this is a challenging task because these distant quasars are incredibly faint.

    “You have to calibrate these measurements very carefully to make sure you really understand what the quasar system is doing,” says Jon Trump, an assistant professor at the University of Connecticut and a member of the research team.

    Improvements in the calibrations were obtained by also observing the quasars with the Canada-France-Hawaii-Telescope (CFHT) and the Steward Observatory Bok telescope located at Kitt Peak over the same observing season.


    CFHT, at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    Bok Telescope U Arizona Steward Observatory, 2.3-metre Bok Telescope at the Steward Observatory at Kitt Peak in Arizona, USA altitude 2,096 m (6,877 ft)

    After all of the observations were compiled and the calibration process was completed, the team found reverberation time delays for 44 quasars. They used these time delay measurements to calculate black hole masses that range from about 5 million to 1.7 billion times the mass of our Sun.

    “This is a big step forward for quasar science,” says Aaron Barth, a professor of astronomy at the University of California, Irvine who was not involved in the team’s research. “They have shown for the first time that these difficult measurements can be done in mass-production mode.”

    These new SDSS measurements increase the total number of active galaxies with SMBH mass measurements by about two-thirds, and push the measurements farther back in time to when the Universe was only half of its current age. But the team isn’t stopping there — they continue to observe these 850 quasars with SDSS, and the additional years of data will allow them to measure black hole masses in even more distant quasars, which have longer time delays that cannot be measured with a single year of data.

    “Getting observations of quasars over multiple years is crucial to obtain good measurements,” says Yue Shen, an assistant professor at the University of Illinois and Principal Investigator of the SDSS Reverberation Mapping project. “As we continue our project to monitor more and more quasars for years to come, we will be able to better understand how supermassive black holes grow and evolve.”

    The future of the SDSS holds many more exciting possibilities for using reverberation mapping to measure masses of supermassive black holes across the Universe. After the current fourth phase of the SDSS ends in 2020, the fifth phase of the program, SDSS-V, begins. SDSS-V features a new program called the Black Hole Mapper, which plans to measure SMBH masses in more than 1,000 more quasars, pushing farther out into the Universe than any reverberation mapping project ever before.

    “The Black Hole Mapper will let us move into the age of supermassive black hole reverberation mapping on a true industrial scale,” says Niel Brandt, a professor of Astronomy & Astrophysics at the Pennsylvania State University and a long-time member of the SDSS. “We will learn more about these mysterious objects than ever before.”

    See the full article here.

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    The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects. Learn and explore all phases and surveys—past, present, and future—of the SDSS.

    The SDSS began regular survey operations in 2000, after a decade of design and construction. It has progressed through several phases, SDSS-I (2000-2005), SDSS-II (2005-2008), SDSS-III (2008-2014), and SDSS-IV (2014-). Each of these phases has involved multiple surveys with interlocking science goals. The three surveys that comprise SDSS-IV are eBOSS, APOGEE-2, and MaNGA, described at the links below. You can find more about the surveys of SDSS I-III by following the Prior Surveys link.

    Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS- IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is http://www.sdss.org.

    SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU) / University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg), Max-Planck-Institut für Astrophysik (MPA Garching), Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatório Nacional / MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University.

     
  • richardmitnick 2:17 pm on January 1, 2018 Permalink | Reply
    Tags: , , , , Supermassive Black Holes, Supermassive black holes control star formation in large galaxies,   

    From UCSC: “Supermassive black holes control star formation in large galaxies” 

    UC Santa Cruz

    UC Santa Cruz

    January 01, 2018
    Tim Stephens
    stephens@ucsc.edu

    1
    This artist’s concept depicts a supermassive black hole at the center of a galaxy. The blue color here represents radiation pouring out from material very close to the black hole. The grayish structure surrounding the black hole, called a torus, is made up of gas and dust. Credit: NASA/JPL-Caltech.

    2
    The power of a supermassive black hole is seen in this image of Centaurus A, one of the active galactic nuclei closest to Earth. The image combines data from several telescopes at different wavelengths, showing jets and lobes powered by the supermassive black hole at the center of the galaxy. Image credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

    ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres

    MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres

    ESO/APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)

    NASA/Chandra Telescope

    Young galaxies blaze with bright new stars forming at a rapid rate, but star formation eventually shuts down as a galaxy evolves. A new study, published January 1, 2018, in Nature, shows that the mass of the black hole in the center of the galaxy determines how soon this “quenching” of star formation occurs.

    Every massive galaxy has a central supermassive black hole, more than a million times more massive than the sun, revealing its presence through its gravitational effects on the galaxy’s stars and sometimes powering the energetic radiation from an active galactic nucleus (AGN). The energy pouring into a galaxy from an active galactic nucleus is thought to turn off star formation by heating and dispelling the gas that would otherwise condense into stars as it cooled.

    This idea has been around for decades, and astrophysicists have found that simulations of galaxy evolution must incorporate feedback from the black hole in order to reproduce the observed properties of galaxies. But observational evidence of a connection between supermassive black holes and star formation has been lacking, until now.

    “We’ve been dialing in the feedback to make the simulations work out, without really knowing how it happens,” said Jean Brodie, professor of astronomy and astrophysics at UC Santa Cruz and a coauthor of the paper. “This is the first direct observational evidence where we can see the effect of the black hole on the star formation history of the galaxy.”

    The new results reveal a continuous interplay between black hole activity and star formation throughout a galaxy’s life, affecting every generation of stars formed as the galaxy evolves.

    Led by first author Ignacio Martín-Navarro, a postdoctoral researcher at UC Santa Cruz, the study focused on massive galaxies for which the mass of the central black hole had been measured in previous studies by analyzing the motions of stars near the center of the galaxy. To determine the star formation histories of the galaxies, Martín-Navarro analyzed detailed spectra of their light obtained by the Hobby-Eberly Telescope Massive Galaxy Survey.

    U Texas Austin McDonald Observatory Hobby-Eberly Telescope, Altitude 2,026 m (6,647 ft)

    Spectroscopy enables astronomers to separate and measure the different wavelengths of light from an object. Martín-Navarro used computational techniques to analyze the spectrum of each galaxy and recover its star formation history by finding the best combination of stellar populations to fit the spectroscopic data. “It tells you how much light is coming from stellar populations of different ages,” he said.

    When he compared the star formation histories of galaxies with black holes of different masses, he found striking differences. These differences only correlated with black hole mass and not with galactic morphology, size, or other properties.

    “For galaxies with the same mass of stars but different black hole mass in the center, those galaxies with bigger black holes were quenched earlier and faster than those with smaller black holes. So star formation lasted longer in those galaxies with smaller central black holes,” Martín-Navarro said.

    Other researchers have looked for correlations between star formation and the luminosity of active galactic nuclei, without success. Martín-Navarro said that may be because the time scales are so different, with star formation occurring over hundreds of millions of years, while outbursts from active galactic nuclei occur over shorter periods of time.

    A supermassive black hole is only luminous when it is actively gobbling up matter from its host galaxy’s inner regions. Active galactic nuclei are highly variable and their properties depend on the size of the black hole, the rate of accretion of new material falling onto the black hole, and other factors.

    “We used black hole mass as a proxy for the energy put into the galaxy by the AGN, because accretion onto more massive black holes leads to more energetic feedback from active galactic nuclei, which would quench star formation faster,” Martín-Navarro explained.

    The precise nature of the feedback from the black hole that quenches star formation remains uncertain, according to coauthor Aaron Romanowsky, an astronomer at San Jose State University and UC Observatories.

    “There are different ways a black hole can put energy out into the galaxy, and theorists have all kinds of ideas about how quenching happens, but there’s more work to be done to fit these new observations into the models,” Romanowsky said.

    In addition to Martín-Navarro, Brodie, and Romanowsky, the coauthors of the paper include Tomás Ruiz Lara at the Institute of Astrophysics of the Canary Islands in Tenerife, Spain, and Glenn van de Ven at UC Observatories and the European Southern Observatory. This research was funded by the U.S. National Science Foundation, the Spanish Ministry of Economy and Competitiveness, and the European Union Horizon 2020 research and innovation program.

    See the full article here .

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    UCO Lick Shane Telescope
    UCO Lick Shane Telescope interior
    Shane Telescope at UCO Lick Observatory, UCSC

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA

    UC Santa Cruz campus
    The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

    UCSC is the home base for the Lick Observatory.

    Lick Observatory's Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building
    Lick Observatory’s Great Lick 91-centimeter (36-inch) telescope housed in the South (large) Dome of main building

    Search for extraterrestrial intelligence expands at Lick Observatory
    New instrument scans the sky for pulses of infrared light
    March 23, 2015
    By Hilary Lebow
    1
    The NIROSETI instrument saw first light on the Nickel 1-meter Telescope at Lick Observatory on March 15, 2015. (Photo by Laurie Hatch) UCSC Lick Nickel telescope

    Astronomers are expanding the search for extraterrestrial intelligence into a new realm with detectors tuned to infrared light at UC’s Lick Observatory. A new instrument, called NIROSETI, will soon scour the sky for messages from other worlds.

    “Infrared light would be an excellent means of interstellar communication,” said Shelley Wright, an assistant professor of physics at UC San Diego who led the development of the new instrument while at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics.

    Wright worked on an earlier SETI project at Lick Observatory as a UC Santa Cruz undergraduate, when she built an optical instrument designed by UC Berkeley researchers. The infrared project takes advantage of new technology not available for that first optical search.

    Infrared light would be a good way for extraterrestrials to get our attention here on Earth, since pulses from a powerful infrared laser could outshine a star, if only for a billionth of a second. Interstellar gas and dust is almost transparent to near infrared, so these signals can be seen from great distances. It also takes less energy to send information using infrared signals than with visible light.

    5
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)

    Frank Drake, professor emeritus of astronomy and astrophysics at UC Santa Cruz and director emeritus of the SETI Institute, said there are several additional advantages to a search in the infrared realm.

    “The signals are so strong that we only need a small telescope to receive them. Smaller telescopes can offer more observational time, and that is good because we need to search many stars for a chance of success,” said Drake.

    The only downside is that extraterrestrials would need to be transmitting their signals in our direction, Drake said, though he sees this as a positive side to that limitation. “If we get a signal from someone who’s aiming for us, it could mean there’s altruism in the universe. I like that idea. If they want to be friendly, that’s who we will find.”

    Scientists have searched the skies for radio signals for more than 50 years and expanded their search into the optical realm more than a decade ago. The idea of searching in the infrared is not a new one, but instruments capable of capturing pulses of infrared light only recently became available.

    “We had to wait,” Wright said. “I spent eight years waiting and watching as new technology emerged.”

    Now that technology has caught up, the search will extend to stars thousands of light years away, rather than just hundreds. NIROSETI, or Near-Infrared Optical Search for Extraterrestrial Intelligence, could also uncover new information about the physical universe.

    “This is the first time Earthlings have looked at the universe at infrared wavelengths with nanosecond time scales,” said Dan Werthimer, UC Berkeley SETI Project Director. “The instrument could discover new astrophysical phenomena, or perhaps answer the question of whether we are alone.”

    NIROSETI will also gather more information than previous optical detectors by recording levels of light over time so that patterns can be analyzed for potential signs of other civilizations.

    “Searching for intelligent life in the universe is both thrilling and somewhat unorthodox,” said Claire Max, director of UC Observatories and professor of astronomy and astrophysics at UC Santa Cruz. “Lick Observatory has already been the site of several previous SETI searches, so this is a very exciting addition to the current research taking place.”

    NIROSETI will be fully operational by early summer and will scan the skies several times a week on the Nickel 1-meter telescope at Lick Observatory, located on Mt. Hamilton east of San Jose.

    The NIROSETI team also includes Geoffrey Marcy and Andrew Siemion from UC Berkeley; Patrick Dorval, a Dunlap undergraduate, and Elliot Meyer, a Dunlap graduate student; and Richard Treffers of Starman Systems. Funding for the project comes from the generous support of Bill and Susan Bloomfield.

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    UCSC is the home base for the Lick Observatory.

     
  • richardmitnick 5:09 pm on December 26, 2017 Permalink | Reply
    Tags: 'Direct Collapse' Black Holes May Explain Our Universe's Mysterious Quasars, , , , , , , , , , , Star formation is a violent process, Supermassive Black Holes,   

    From Ethan Siegel: “‘Direct Collapse’ Black Holes May Explain Our Universe’s Mysterious Quasars” 

    From Ethan Siegel
    Dec 26, 2017

    1
    The most distant X-ray jet in the Universe, from quasar GB 1428, is approximately the same distance and age, as viewed from Earth, as quasar S5 0014+81; both are over 12 billion light years away. X-ray: NASA/CXC/NRC/C.Cheung et al; Optical: NASA/STScI; Radio: NSF/NRAO/VLA

    NASA/Chandra Telescope


    NASA/ESA Hubble Telescope


    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    There’s a big problem when we look at the brightest, most energetic objects we can see in the early stages of the Universe. Shortly after the first stars and galaxies form, we find the first quasars: extremely luminous sources of radiation that span the electromagnetic spectrum, from radio up through the X-ray. Only a supermassive black hole could possibly serve as the engine for one of these cosmic behemoths, and the study of active objects like quasars, blazars, and AGNs all support this idea. But there’s a problem: it may not be possible to make a black hole so large, so quickly, to explain these young quasars that we see. Unless, that is, there’s a new way to make black holes beyond what we previously thought. This year, we found the first evidence for a direct collapse black hole, and it may lead to the solution we’ve sought for so long.

    2
    While distant host galaxies for quasars and active galactic nuclei can often be imaged in visible/infrared light, the jets themselves and the surrounding emission is best viewed in both the X-ray and the radio, as illustrated here for the galaxy Hercules A. It takes a black hole to power an engine such as this. NASA, ESA, S. Baum and C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA).

    Generically known as ‘active galaxies,’ almost all galaxies posses supermassive black holes at their center, but only a few emit the intense radiation associated with quasars or AGNs. The leading idea is that supermassive black holes will feed on matter, accelerating and heating it, which causes it to ionize and give off light. Based on the light we observe, we can successfully infer the mass of the central black hole, which often reaches billions of times the mass of our Sun. Even for the earliest quasars, such as J1342+0928, we can get up to a mass of 800 million solar masses just 690 million years after the Big Bang: when the Universe was just 5% of its current age.

    3
    This artist’s concept shows the most distant supermassive black hole ever discovered. It is part of a quasar from just 690 million years after the Big Bang. Robin Dienel/Carnegie Institution for Science.

    If you try to build a black hole in the conventional way, by having massive stars go supernova, form small black holes, and have them merge together, you run into problems. Star formation is a violent process, as when nuclear fusion ignites, the intense radiation burns off the remaining gas that would otherwise go into forming progressively more and more massive stars. From nearby star-forming regions to the most distant ones we’ve ever observed, this same process seems to be in place, preventing stars (and, hence, black holes) beyond a certain mass from ever forming.

    4
    An artist’s conception of what the Universe might look like as it forms stars for the first time. While stars might reach many hundreds or even a thousand solar masses, it’s very difficult to see how you could get a black hole of the mass the earliest quasars are known to possess. NASA/JPL-Caltech/R. Hurt (SSC).

    We have a standard scenario that’s very powerful and compelling: of supernova explosions, gravitational interactions, and then growth by mergers and accretion. But the early quasars we see are too massive too quickly to be explained by this. Our other known pathway to create black holes, from merging neutron stars, provides no further help. Instead, a third scenario of direct collapse may be responsible. This idea has been helped along by three pieces of evidence in the past year:

    1.The discovery of ultra-young quasars like J1342+0928, in possession of black holes many hundred of millions of solar masses.
    2.Theoretical advances that show how, if the direct collapse scenario is true, we could form early “seed” black holes a thousand times as massive as the ones formed by supernova.
    3.And the discovery of the first stars that become black holes via direct collapse, validating the process.

    5
    In addition to formation by supernovae and neutron star mergers, it should be possible for black holes to form via direct collapse. Simulations such as the one shown here demonstrate that, under the right condition, seed black holes of 100,000 to 1,000,000 solar masses could form in the very early stages of the Universe. Aaron Smith/TACC/UT-Austin.

    Normally, it’s the hottest, youngest, most massive, and newest stars in the Universe that will lead to a black hole. There are plenty of galaxies like this in the early stages of the Universe, but there are also plenty of proto-galaxies that are all gas, dust, and dark matter, with no stars in them yet. Out in the great cosmic abyss, we’ve even found an example of a pair of galaxies just like this: where one has furiously formed stars and the other one may not have formed any yet. The ultra-distant galaxy, known as CR7, has a massive population of young stars, and a nearby patch of light-emitting gas that may not have yet formed a single star in it.

    6
    Illustration of the distant galaxy CR7, which last year was discovered to house a pristine population of stars formed from the material direct from the Big Bang. One of these galaxies definitely houses stars; the other may not have formed any yet. M. Kornmesser / ESO.

    In a theoretical study published in March [Nature Astronomy] of this year, a fascinating mechanism for producing direct collapse black holes from a mechanism like this was introduced. A young, luminous galaxy could irradiate a nearby partner, which prevents the gas within it from fragmenting to form tiny clumps. Normally, it’s the tiny clumps that collapse into individual stars, but if you fail to form those clumps, you instead can just get a monolithic collapse of a huge amount of gas into a single bound structure. Gravitation then does its thing, and your net result could be a black hole over 100,000 times as massive as our Sun, perhaps even all the way up to 1,000,000 solar masses.

    6
    Distant, massive quasars show ultramassive black holes in their cores. It’s very difficult to form them without a large seed, but a direct collapse black hole could solve that puzzle quite elegantly. J. Wise/Georgia Institute of Technology and J. Regan/Dublin City University.

    There are many theoretical mechanisms that turn out to be intriguing, however, that aren’t borne out when it comes to real, physical environments. Is direct collapse possible? We can now definitively answer that question with a “yes,” as the first star that was massive enough to go supernova was seen to simply wink out of existence. No fireworks; no explosion; no increase in luminosity. Just a star that was there one moment, and replaces with a black hole the next. As spotted before-and-after with Hubble, there is no doubt that the direct collapse of matter to a black hole occurs in our Universe.

    7
    The visible/near-IR photos from Hubble show a massive star, about 25 times the mass of the Sun, that has winked out of existence, with no supernova or other explanation. Direct collapse is the only reasonable candidate explanation. NASA/ESA/C. Kochanek (OSU).

    Put all three of these pieces of information together, and you arrive at the following picture for how these supermassive black holes form so early.

    A region of space collapses to form stars, while a nearby region of space has also undergone gravitational collapse but hasn’t formed stars yet.
    The region with stars emits an intense amount of radiation, where the photon pressure keeps the gas in the other cloud from fragmenting into potential stars.
    The cloud itself continues to collapse, doing so in a monolithic fashion. It expels energy (radiation) as it does so, but without any stars inside.
    When a critical threshold is crossed, that huge amount of mass, perhaps hundreds of thousands or even millions of times the mass of our Sun, directly collapses to form a black hole.
    From this massive, early seed, it’s easy to get supermassive black holes simply by the physics of gravitation, merger, accretion, and time.

    It might not only be possible, but with the new array of radio telescopes coming online, as well as the James Webb Space Telescope, we may be able to witness the process in action.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    SKA Square Kilometer Array


    SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia


    SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    The galaxy CR7 is likely one example of many similar objects likely to be out there. As Volker Bromm, the theorist behind the direct collapse mechanism first said [RAS], a nearby, luminous galaxy could cause a nearby cloud of gas to directly collapse. All you need to do is begin with a

    “primordial cloud of hydrogen and helium, suffused in a sea of ultraviolet radiation. You crunch this cloud in the gravitational field of a dark-matter halo. Normally, the cloud would be able to cool, and fragment to form stars. However, the ultraviolet photons keep the gas hot, thus suppressing any star formation. These are the desired, near-miraculous conditions: collapse without fragmentation! As the gas gets more and more compact, eventually you have the conditions for a massive black hole.”

    8
    The directly collapsing star we observed exhibited a brief brightening before having its luminosity drop to zero, an example of a failed supernova. For a large cloud of gas, the luminous emission of light is expected, but no stars are necessary to form a black hole this way.
    NASA/ESA/P. Jeffries (STScI)

    With a little luck, by time 2020 rolls around, this is one longstanding mystery that might finally be solved.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 3:08 pm on December 20, 2017 Permalink | Reply
    Tags: 3C 298 host galaxy, , , , , , Shelley Wright of UCSD, Supermassive Black Holes   

    From Keck: “Astronomers Shed Light on Formation of Black Holes and Galaxies” 

    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft) above sea level, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    December 20, 2017
    No writer credit

    4
    Image of the quasar host galaxy from the UC San Diego research team’s data. The distance to this quasar galaxy is ~9.3 billion light years. The four-color image shows findings from use of the Keck Observatory and ALMA. As seen from Keck Observatory, the green colors highlight the energetic gas across the galaxy that is being illuminated by the quasar. The blue color represents powerful winds blowing throughout the galaxy. The red-orange colors represent the cold molecular gas in the system as seen from ALMA. The supermassive black hole sits at the center of the bright red-orange circular area slightly below the middle of the image. Credit: A. VAYNER AND TEAM

    Stars forming in galaxies appear to be influenced by the supermassive black hole at the center of the galaxy, but the mechanism of how that happens has not been clear to astronomers until now.

    “Supermassive black holes are captivating,” says lead author Shelley Wright, a University of California San Diego Professor of Physics.

    3
    UCSC alumna Shelley Wright, now an assistant professor of physics at UC San Diego, discusses the dichroic filter of the NIROSETI instrument. (Photo by Laurie Hatch)
    4
    NIROSETI AT UCSC Lick Observatory, attached to the existing Nickel 1-meter telescope, developed at Dunlap Institute, U Toronto

    “Understanding why and how galaxies are affected by their supermassive black holes is an outstanding puzzle in their formation, says Wright”

    In a study published today in The Astrophysical Journal,
    Wright, graduate student Andrey Vayner, and their colleagues examined the energetics surrounding the powerful winds generated by the bright, vigorous supermassive black hole (known as a “quasar”) at the center of the 3C 298 host galaxy, located approximately 9.3 billion light years away.

    “We study supermassive black holes in the very early universe when they are actively growing by accreting massive amounts of gaseous material,” says Wright. “While black holes themselves do not emit light, the gaseous material they chew on is heated to extreme temperatures, making them the most luminous objects in the universe.”

    The UC San Diego team’s research revealed that the winds blow out through the entire galaxy and impact the growth of stars.

    “This is remarkable that the supermassive black hole is able to impact stars forming at such large distances,” says Wright.

    Today, neighboring galaxies show that the galaxy mass is tightly correlated with the supermassive black hole mass. Wright’s and Vayner’s research indicates that 3C 298 does not fall within this normal scaling relationship between nearby galaxies and the supermassive black holes that lurk at their center. But, in the early universe, their study shows that the 3C 298 galaxy is 100 times less massive than it should be given its behemoth supermassive black hole mass.

    This implies that the supermassive black hole mass is established well before the galaxy, and potentially the energetics from the quasar are capable of controlling the growth of the galaxy.

    To conduct the study, the UC San Diego researchers utilized multiple state-of-the-art astronomical facilities. The first of these was Keck Observatory’s instrument OSIRIS (OH-Suppressing Infrared Imaging Spectrograph) and its advanced adaptive optics (AO) system.

    Keck OSIRIS

    An AO system allows ground-based telescopes to achieve higher quality images by correcting for the blurring caused by the Earth’s atmosphere. The resulting images are as good as those obtained from space.

    The second major facility was the Atacama Large Millimeter/submillimeter Array, known as “ALMA,” an international observatory in Chile that is able to detect millimeter wavelengths using up to 66 antennae to achieve high-resolution images of the gas surrounding the quasar.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    “The most enjoyable part of researching this galaxy has been putting together all the data from different wavelengths and techniques,” said Vayner. “Each new dataset that we obtained on this galaxy answered one question and helped us put some of the pieces of the puzzle together. However, at the same time, it created new questions about the nature of galaxy and supermassive black hole formation.”

    Wright agreed, saying that the data sets were “tremendously gorgeous” from both Keck Observatory and ALMA, offering a wealth of new information about the universe.

    These findings are the first results from a larger survey of distant quasars and their energetics’ impact on star formation and galaxy growth. Vayner and the team will continue developing results on more distant quasars using the new facilities and capabilities from Keck Observatory and ALMA.

    See the full article here .

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.


    Keck UCal

     
  • richardmitnick 8:40 pm on December 17, 2017 Permalink | Reply
    Tags: , , Atacama Desert of Chile so important for Optical Astonomy, , Carnegie Institution for Science Las Campanas Observatory, , , Earliest Black Hole Gives Rare Glimpse of Ancient Universe, , , , Supermassive Black Holes   

    From Quanta: “Earliest Black Hole Gives Rare Glimpse of Ancient Universe” 

    Quanta Magazine
    Quanta Magazine

    December 6, 2017 [Today in social media]
    Joshua Sokol

    1
    Olena Shmahalo/Quanta Magazine

    2
    The two Carnegie Magellan telescopes: Baade (left) and Clay (right)

    Astronomers have at least two gnawing questions about the first billion years of the universe, an era steeped in literal fog and figurative mystery. They want to know what burned the fog away: stars, supermassive black holes, or both in tandem? And how did those behemoth black holes grow so big in so little time?

    Now the discovery of a supermassive black hole smack in the middle of this period is helping astronomers resolve both questions. “It’s a dream come true that all of these data are coming along,” said Avi Loeb, the chair of the astronomy department at Harvard University.

    The black hole, announced today in the journal Nature, is the most distant ever found. It dates back to 690 million years after the Big Bang. Analysis of this object reveals that reionization, the process that defogged the universe like a hair dryer on a steamy bathroom mirror, was about half complete at that time.

    First Stars and Reionization Era, Caltech

    The researchers also show that the black hole already weighed a hard-to-explain 780 million times the mass of the sun.

    A team led by Eduardo Bañados, an astronomer at the Carnegie Institution for Science in Pasadena, found the new black hole by searching through old data for objects with the right color to be ultradistant quasars — the visible signatures of supermassive black holes swallowing gas. The team went through a preliminary list of candidates, observing each in turn with a powerful telescope at Las Campanas Observatory in Chile.

    4
    Carnegie Institution for Science Las Campanas Observatory telescopes in the southern Atacama Desert of Chile approximately 100 kilometres (62 mi) northeast of the city of La Serena,near the southern end and over 2,500 m (8,200 ft) high.

    On March 9, Bañados observed a faint dot in the southern sky for just 10 minutes. A glance at the raw, unprocessed data confirmed it was a quasar — not a nearer object masquerading as one — and that it was perhaps the oldest ever found. “That night I couldn’t even sleep,” he said.

    3
    Eduardo Bañados at the Las Campanas Observatory in Chile, where the new quasar was discovered. Courtesy of Eduardo Bañados. Baade and Clay in the background.

    The new black hole’s mass, calculated after more observations, adds to an existing problem. Black holes grow when cosmic matter falls into them. But this process generates light and heat. At some point, the radiation released by material as it falls into the black hole carries out so much momentum that it blocks new gas from falling in and disrupts the flow. This tug-of-war creates an effective speed limit for black hole growth called the Eddington rate. If this black hole began as a star-size object and grew as fast as theoretically possible, it couldn’t have reached its estimated mass in time.

    Other quasars share this kind of precocious heaviness, too. The second-farthest one known, reported on in 2011, tipped the scales at an estimated 2 billion solar masses after 770 million years of cosmic time.

    These objects are too young to be so massive. “They’re rare, but they’re very much there, and we need to figure out how they form,” said Priyamvada Natarajan, an astrophysicist at Yale University who was not part of the research team. Theorists have spent years learning how to bulk up a black hole in computer models, she said. Recent work suggests that these black holes could have gone through episodic growth spurts during which they devoured gas well over the Eddington rate.

    Bañados and colleagues explored another possibility: If you start at the new black hole’s current mass and rewind the tape, sucking away matter at the Eddington rate until you approach the Big Bang, you see it must have initially formed as an object heavier than 1,000 times the mass of the sun. In this approach, collapsing clouds in the early universe gave birth to overgrown baby black holes that weighed thousands or tens of thousands of solar masses. Yet this scenario requires exceptional conditions that would have allowed gas clouds to condense all together into a single object instead of splintering into many stars, as is typically the case.

    Cosmic Dark Ages

    2
    Cosmic Dark Ages. ESO.

    Even earlier in the early universe, before any stars or black holes existed, the chaotic scramble of naked protons and electrons came together to make hydrogen atoms. These neutral atoms then absorbed the bright ultraviolet light coming from the first stars. After hundreds of millions of years, young stars or quasars emitted enough light to strip the electrons back off these atoms, dissipating the cosmic fog like mist at dawn.

    3
    Lucy Reading-Ikkanda/Quanta Magazine

    Astronomers have known that reionization was largely complete by around a billion years after the Big Bang.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    At that time, only traces of neutral hydrogen remained. But the gas around the newly discovered quasar is about half neutral, half ionized, which indicates that, at least in this part of the universe, reionization was only half finished. “This is super interesting, to really map the epoch of reionization,” said Volker Bromm, an astrophysicist at the University of Texas.

    When the light sources that powered reionization first switched on, they must have carved out the opaque cosmos like Swiss cheese.

    Inflationary Universe. NASA/WMAP

    But what these sources were, when it happened, and how patchy or homogeneous the process was are all debated. The new quasar shows that reionization took place relatively late. That scenario squares with what the known population of early galaxies and their stars could have done, without requiring astronomers to hunt for even earlier sources to accomplish it quicker, said study coauthor Bram Venemans of the Max Planck Institute for Astronomy in Heidelberg.

    More data points may be on the way. For radio astronomers, who are gearing up to search for emissions from the neutral hydrogen itself, this discovery shows that they are looking in the right time period. “The good news is that there will be neutral hydrogen for them to see,” said Loeb. “We were not sure about that.”

    The team also hopes to identify more quasars that date back to the same time period but in different parts of the early universe. Bañados believes that there are between 20 and 100 such very distant, very bright objects across the entire sky. The current discovery comes from his team’s searches in the southern sky; next year, they plan to begin searching in the northern sky as well.

    “Let’s hope that pans out,” said Bromm. For years, he said, the baton has been handed off between different classes of objects that seem to give the best glimpses at early cosmic time, with recent attention often going to faraway galaxies or fleeting gamma-ray bursts. “People had almost given up on quasars,” he said.

    See the full article here .

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

     
  • richardmitnick 8:18 am on November 30, 2017 Permalink | Reply
    Tags: , Are Spinning Black Holes Louder?, , , , , Supermassive Black Holes   

    From AAS NOVA: “Are Spinning Black Holes Louder?” 

    AASNOVA

    AAS NOVA

    29 November 2017
    Susanna Kohler

    1
    Artist’s impression of a distant quasar sporting a relativistic jet. Could the radio-loudness of such a quasar depend on its central black hole’s spin? [ESO/M. Kornmesser]

    2
    A cloud of gas surrounds the distant quasar SDSS J102009.99+104002.7 in this image from ESO’s Very Large Telescope.

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    The name “quasar” is a shortening of “quasi-stellar radio source”, though we now know that only a small fraction of quasars are radio-loud. [ESO/Arrigoni Battaia et al.]

    Some distant active galaxies are louder in radio wavelengths than others. A new study explores whether this difference could be due to how quickly the supermassive black holes at their centers are spinning.

    Loud and Quiet Quasars

    Quasars, the most luminous type of active galactic nuclei, are powered by the accretion of material onto the supermassive black holes located at the centers of the galaxies. These distant beasts tend to fall into two general categories:

    1. radio-loud quasars, which host powerful relativistic radio jets and make up roughly 10% of the quasar population, and
    2. radio-quiet quasars, which feature only weak core radio emission and make up the remaining 90% of quasars.

    What causes this distinction in jet behavior? Many theories have been put forward, but today we’ll explore one potential factor in particular: the spin of the black hole.

    3
    Histogram of the [O III] equivalent width for radio-loud (solid red) vs. radio-quiet (dashed blue) quasars, for three different definitions of radio-loudness. [Adapted from Schulze et al. 2017]

    In the spin paradigm, it’s postulated that the angular momentum from a black hole’s spin — which can be retrograde, prograde, or nonexistent — is what allows (or doesn’t allow) for the launch of relativistic jets. In this picture, radio-loud quasars should have rapidly spinning supermassive black holes at their centers, whereas radio-quiet quasars should host low-spin black holes.

    A Tricky Measurement

    Past studies examining the spin paradigm suggest that it doesn’t hold up — several radio-quiet quasars were found to host black holes with apparently high spin. But measuring black-hole spins is notoriously tricky, with each method relying on a number of inferences. It’s possible that the method used to infer the high spins of these radio-quiet quasars might not have yielded accurate results.

    A team of scientists led by Andreas Schulze (National Astronomical Observatory of Japan) has now proposed an alternative approach to test the spin paradigm. Schulze and collaborators suggest using the strength of a particular emission line, [O III], to indirectly measure the black holes’ average radiative efficiency — i.e., how much of the energy of the mass accreting onto the black holes is converted into radiation. If the average efficiency for a sample of radio-loud quasars is different than that for a sample of radio-quiet quasars, this would mean a difference in black-hole spins for the two samples.

    Counting Spin Back In

    4
    [O III] equivalent width for the radio-loud (solid red) and radio-quiet (dashed blue) samples as a function of redshift. [Schulze et al. 2017]

    Using a sample of nearly 8,000 quasars identified in the Sloan Digital Sky Survey, the authors find that the [O III] line strength is enhanced by a factor of at least 1.5 in a radio-loud sample, compared to a radio-quiet sample matched in redshift, black-hole mass, and accretion rate.

    SDSS Telescope at Apache Point Observatory, NM, USA, Altitude 2,788 meters (9,147 ft)

    Schulze and collaborators argue that this suggests the black-hole spins of the radio-loud quasar population are systematically higher than those of the radio-quiet population.

    The authors caution that, like other tactics used to learn about black-hole spins, their approach relies on a number of key assumptions — and their results certainly don’t mean that spin must be the only factor differentiating between radio-loud and radio-quiet quasars. The results do suggest, however, that we shouldn’t count spin out of the game: it may play an important role in determining the loudness of these distant accreting monsters.

    Citation

    Andreas Schulze et al 2017 ApJ 849 4. doi:10.3847/1538-4357/aa9181

    Related Journal Articles
    See the full article for further references with links.

    See the full article here .

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    1

    AAS Mission and Vision Statement

    The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

    The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
    The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
    The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
    The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
    The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

    Adopted June 7, 2009

     
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