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  • richardmitnick 10:11 am on May 23, 2016 Permalink | Reply
    Tags: , , , , NASA Chandra   

    From Daily Galaxy: “”Attempt No Journey There” –Swarm of 10,000 Black Holes and Neutron Stars Orbit Milky Way’s Supermassive Black Hole” 

    Daily Galaxy
    The Daily Galaxy

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    No image caption, no image credit

    May 22, 2016

    “The giant black holes in the cores of galaxies, a million to 20 billion times heavier than the Sun, therefore, cannot have been born in the death of a star. They must have formed in some other way, perhaps by the agglomeration of many smaller black holes; perhaps by the collapse of massive clouds of gas.” ― Kip S. Thorne, The Science of Interstellar.

    “The Center of our Milky Way Galaxy is a place of extremes,” says Mark Morris, an expert on The Galactic Center at UCLA. “For every star in our nighttime sky, for example, there would be a million for someone looking up from a planet near the Galactic center.”

    Thinking about a far-future visit to our galaxy’s central zone, brings to mind Arthur C. Clark’s admonition about a visit to Jupiter’s ocean moon, Europa –“All These Worlds are Yours –Except Europa Attempt No Landing There.” In addition to the extreme star density, a swarm of 10,000 or more black holes may be orbiting the Milky Way’s supermassive black hole, according to observations from NASA’s Chandra X-ray Observatory in 2015.

    Sag A*  NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way
    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way”

    This would represent the highest concentration of black holes anywhere in the Galaxy. These relatively small, stellar-mass black holes, along with neutron stars, appear to have migrated into the Galactic Center over the course of several billion years. Could this migration be the prelude to feeding our supermassive black hole suggested by Caltech’s Kip Thorne?

    The discovery was made as part of Chandra’s ongoing program of monitoring the region around Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, reported by by Michael Muno of the University of California, Los Angeles (UCLA) at a 2015 meeting of the American Astronomical Society.

    Among the thousands of X-ray sources detected within 70 light years of Sgr A*, Muno and his colleagues searched for those most likely to be active black holes and neutron stars by selecting only the brightest sources that also exhibited large variations in their X-ray output. These characteristics identify black holes and neutron stars that are in binary star systems and are pulling matter from nearby companion stars. Of the seven sources that met these criteria, four are within three light years of Sgr A*.

    “Although the region around Sgr A* is crowded with stars, we expected that there was only a 20 percent chance that we would find even one X-ray binary within a three-light-year radius,” said Muno. “The observed high concentration of these sources implies that a huge number of black holes and neutron stars have gathered in the center of the Galaxy.”

    Mark Morris, also of UCLA and a coauthor on the present work, had predicted a decade ago that a process called dynamical friction would cause stellar black holes to sink toward the center of the Galaxy. Black holes are formed as remnants of the explosions of massive stars and have masses of about 10 suns. As black holes orbit the center of the Galaxy at a distance of several light years, they pull on surrounding stars, which pull back on the black holes.

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    Unidentified. No image credit.

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    The images above are part of a Chandra program that monitors a region around the Milky Way’s supermassive black hole, Sagittarius A* (Sgr A*). Four bright, variable X-ray sources (circles) were discovered within 3 light years of Sgr A* (the bright source just above Source C). The lower panel illustrates the strong variability of one of these sources. This variability, which is present in all the sources, is indicative of an X-ray binary system where a black hole or neutron star is pulling matter from a nearby companion star.

    “Stars are packed quite close together in the center zone,” says Morris. “Then, there’s that supermassive black hole that is sitting in there, relatively quiet for now, but occasionally producing a dramatic outpouring of energy. The UCLA Galactic center group been use the Keck Telescopes in Hawaii to follow its activity for the last 17 years, watching not only the fluctuating emission from the black hole, but also watching the stars around it as they rapidly orbit the black hole.”

    Morris had predicted a decade ago that a process called dynamical friction would cause stellar black holes to sink toward the center of the Galaxy. Black holes are formed as remnants of the explosions of massive stars and have masses of about 10 suns. As black holes orbit the center of the Galaxy at a distance of several light years, they pull on surrounding stars, which pull back on the black holes. The net effect is that black holes spiral inward, and the low-mass stars move out. From the estimated number of stars and black holes in the Galactic Center region, dynamical friction is expected to produce a dense swarm of 20,000 black holes within three light years of Sgr A*. A similar effect is at work for neutron stars, but to a lesser extent because they have a lower mass.

    Once black holes are concentrated near Sgr A*, they will have numerous close encounters with normal stars there, some of which are in binary star systems. The intense gravity of a black hole can induce an ordinary star to “change partners” and pair up with the black hole while ejecting its companion. This process and a similar one for neutron stars are expected to produce several hundreds of black hole and neutron star binary systems.

    The black holes and neutron stars in the cluster are expected to gradually be swallowed by the supermassive black hole, Sgr A*, at a rate of about one every million years. At this rate, about 10,000 black holes and neutron stars would have been captured in a few billion years, adding about 3 percent to the mass of the central supermassive black hole, which is currently estimated to contain the mass of 3.7 million suns.

    In the meantime, the acceleration of low-mass stars by black holes will eject low-mass stars from the central region. This expulsion will reduce the likelihood that normal stars will be captured by the central supermassive black hole. This may explain why the central regions of some galaxies, including the Milky Way, are fairly quiet even though they contain a supermassive black hole.

    See the full article here .

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  • richardmitnick 8:03 pm on May 12, 2016 Permalink | Reply
    Tags: , , NASA Chandra, Tycho Supernova Remnant   

    From Chandra: Tycho’s Supernova Remnant from Chandra 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

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    Credit X-ray: NASA/CXC/GSFC/B.Williams et al; Optical: DSS
    Release Date May 12, 2016

    For the first time, a movie has been made of the evolution of Tycho’s supernova remnant.

    This sequence includes X-rays observations from Chandra spaced out over a decade and a half.

    Tycho belongs to a class of supernovas used to measure the expansion of the Universe so the details of these explosions are very important.

    By combining the Chandra data with 30 years worth of observations with the VLA, scientists have learned new things about this remnant and its history.


    Access mp4 video here .
    Video released in 2011

    When the star that created this supernova remnant exploded in 1572, it was so bright that it was visible during the day. And though he wasn’t the first or only person to observe this stellar spectacle, the Danish astronomer Tycho Brahe wrote a book about his extensive observations of the event, gaining the honor of it being named after him.

    In modern times, astronomers have observed the debris field from this explosion – what is now known as Tycho’s supernova remnant – using data from NASA’s Chandra X-ray Observatory, the NSF’s Karl G. Jansky Very Large Array (VLA) and many other telescopes.

    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, New Mexico.
    NRAO/VLA, on the Plains of San Agustin fifty miles west of Socorro, New Mexico

    Today, they know that the Tycho remnant was created by the explosion of a white dwarf star, making it part of the so-called Type Ia class of supernovas used to track the expansion of the Universe.

    Since much of the material being flung out from the shattered star has been heated by shock waves – similar to sonic booms from supersonic planes – passing through it, the remnant glows strongly in X-ray light. Astronomers have now used Chandra observations from 2000 through 2015 to create the longest movie of the Tycho remnant’s X-ray evolution over time, using five different images. This shows the expansion from the explosion is still continuing about 450 years later, as seen from Earth’s vantage point roughly 10,000 light years away.

    By combining the X-ray data with some 30 years of observations in radio waves with the VLA, astronomers have also produced a movie, using three different images. Astronomers have used these X-ray and radio data to learn new things about this supernova and its remnant.

    The researchers measured the speed of the blast wave at many different locations around the remnant. The large size of the remnant enables this motion to be measured with relatively high precision. Although the remnant is approximately circular, there are clear differences in the speed of the blast wave in different regions. The speed in the right and lower right directions is about twice as large as that in the left and the upper left directions. This difference was also seen in earlier observations.

    This range in speed of the blast wave’s outward motion is caused by differences in the density of gas surrounding the supernova remnant. This causes an offset in position of the explosion site from the geometric center, determined by locating the center of the circular remnant. The astronomers found that the size of the offset is about 10% of the remnant’s current radius, towards the upper left of the geometric center. The team also found that the maximum speed of the blast wave is about 12 million miles per hour.

    Offsets such as this between the explosion center and the geometric center could exist in other supernova remnants. Understanding the location of the explosion center for Type Ia supernovas is important because it narrows the search region for a surviving companion star. Any surviving companion star would help identify the trigger mechanism for the supernova, showing that the white dwarf pulled material from the companion star until it reached a critical mass and exploded. The lack of a companion star would favor the other main trigger mechanism, where two white dwarfs merge causing the critical mass to be exceeded, leaving no star behind.

    The significant offset from the center of the explosion to the remnant’s geometric center is a relatively recent phenomenon. For the first few hundred years of the remnant, the explosion’s shock was so powerful that the density of gas it was running into did not affect its motion. The density discrepancy from the left side to the right has increased as the shock moved outwards, causing the offset in position between the explosion center and the geometric center to grow with time. So, if future X-ray astronomers, say 1,000 years from now, do the same observation, they should find a much larger offset.

    A paper* describing these results has been accepted for publication in The Astrophysical Journal Letters and is available online*. The authors are Brian Williams (NASA’s Goddard Space Flight Center), Laura Chomiuk (Michigan State University), John Hewitt (University of North Florida), John Blondin (North Carolina State University), Kazimierz Borkowski (NCSU), Parviz Ghavamian (Towson University), Robert Petre (GSFC), and Stephen Reynolds (NCSU).

    *Science paper:
    An X-ray and Radio Study of the Varying Expansion Velocities in Tycho’s Supernova Remnant

    See the full article here .

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

     
  • richardmitnick 8:38 pm on April 28, 2016 Permalink | Reply
    Tags: , , NASA Chandra, Probing Dark Energy with Clusters   

    From Chandra: “Probing Dark Energy with Clusters: ‘Russian Doll’ Galaxy Clusters Reveal Information About Dark Energy” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    April 28, 2016

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    Composite

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    X-ray

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    Optical

    Fast Facts for Abell 1835:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 7 Dec 2005, 24 Jul and 25 Aug 2006

    Fast Facts for MS 1455.0+2232:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 19 May 2000, 05 Sep 2003, 23 Mar 2007

    Fast Facts for RXJ 1347.5-1145:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 3 Sep 2003, 16 Mar, 14 May and 11 Dec 2012

    Fast Facts for ZWCL 3146:
    Credit X-ray: NASA/CXC/Univ. of Alabama/A. Morandi et al; Optical: SDSS, NASA/STScI
    Release Date April 28, 2016
    Observation Dates 10 May 2000, 18 Jan 2008

    Researchers are using a large sample of galaxy cluster to investigate dark energy.

    The details of X-ray emission from over 300 galaxy clusters were obtained with Chandra.

    The galaxy clusters range in distance from about 760 million to 8.7 billion light years from Earth.

    The study shows that dark energy has not changed over billions of years.

    These four galaxy clusters were part of a large survey of over 300 clusters used to investigate dark energy, the mysterious energy that is currently driving the accelerating expansion of the Universe, as described in our latest press release. In these composite images, X-rays from NASA’s Chandra X-ray Observatory (purple) have been combined with optical light from the Hubble Space Telescope and Sloan Digital Sky Survey (red, green, and blue).

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    SDSS Telescope at Apache Point, NM, USA
    SDSS Telescope at Apache Point, NM, USA

    Researchers used a novel technique that takes advantage of the observation that the outer reaches of galaxy clusters, the largest structures in the universe held together by gravity, show similarity in their X-ray emission profiles and sizes. That is, more massive clusters are simply scaled up versions of less massive ones, similar to Russian dolls that nest inside one another.

    The amount of matter in the Universe, which is dominated by the unseen substance called dark matter, and the properties of dark energy (what astronomers call cosmological parameters) affect the rate of expansion of the Universe and, therefore, how the distances to objects change with time. If the cosmological parameters used are incorrect and a cluster is inferred to be traveling away faster than the correct value, then a cluster will appear to be larger and fainter due to this “Russian doll” property. If the cluster is inferred to be traveling away more slowly than the correct value, the cluster will be smaller and brighter than a cluster according to theory.

    These latest results confirm earlier studies that the amount of dark energy has not changed over billions of years. They also support the idea that dark energy is best explained by the “cosmological constant,” which Einstein first proposed and is equivalent to the energy of empty space.

    The galaxy clusters in this large sample ranged in distance from about 760 million to 8.7 billion light years from Earth, providing astronomers with information about the era where dark energy caused the once-decelerating expansion of the Universe to accelerate.

    The X-ray emission in the outer parts of galaxy clusters is faint because the gas is diffuse there. To deal with this issue in this study, the X-ray signal from different clusters was added together. Regions near the centers of the clusters are excluded from the analysis because of large differences between the properties of different clusters caused by supermassive black hole outbursts, the cooling of gas and the formation of stars.

    A paper describing these results by Andrea Morandi and Ming Sun (University of Alabama at Huntsville) appeared in the April 11th, 2016 issue of the Monthly Notices of the Royal Astronomical Society journal and is available online*.

    *Science paper:
    Probing dark energy via galaxy cluster outskirts

    See the full article here .

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

     
  • richardmitnick 11:06 pm on March 10, 2016 Permalink | Reply
    Tags: , , , NASA Chandra   

    From Chandra: “MACS J0416.1-2403 and MACS J0717.5+3745: Telescopes Combine to Push Frontier on Galaxy Clusters” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    MACS J0416.1-2403 and MACS J0717.5+3745
    Credit X-ray: NASA/CXC/SAO/G.Ogrean et al.; Optical: NASA/STScI; Radio: NRAO/AUI/NSF
    Release Date March 10, 2016

    These two galaxy clusters are part of the “Frontier Fields” project that obtains long observations with multiple telescopes.

    Galaxy clusters are important because they are the largest structures in the Universe held together by gravity.

    Both of these objects are sites where multiple galaxy clusters are colliding.

    X-rays from Chandra reveal the massive amounts of hot gas that pervade each galaxy cluster.

    Galaxy clusters are enormous collections of hundreds or even thousands of galaxies and vast reservoirs of hot gas embedded in massive clouds of dark matter, invisible material that does not emit or absorb light but can be detected through its gravitational effects. These cosmic giants are not merely novelties of size or girth – rather they represent pathways to understanding how our entire universe evolved in the past and where it may be heading in the future.

    To learn more about clusters, including how they grow via collisions, astronomers have used some of the world’s most powerful telescopes, looking at different types of light. They have focused long observations with these telescopes on a half dozen galaxy clusters. The name for this galaxy cluster project is the Frontier Fields.

    Two of these Frontier Fields galaxy clusters, MACS J0416.1-2403 (abbreviated MACS J0416) and MACS J0717.5+3745 (MACS J0717 for short) are featured here in a pair of multi-wavelength images.

    Located about 4.3 billion light years from Earth, MACS J0416 is a pair of colliding galaxy clusters that will eventually combine to form an even bigger cluster. MACS J0717, one of the most complex and distorted galaxy clusters known, is the site of a collision between four clusters. It is located about 5.4 billion light years away from Earth.

    These new images of MACS J0416 and MACS J0717 contain data from three different telescopes: NASA’s Chandra X-ray Observatory (diffuse emission in blue), Hubble Space Telescope (red, green, and blue), and the NSF’s [NRAO] Jansky Very Large Array (diffuse emission in pink). Where the X-ray and radio emission overlap the image appears purple. Astronomers also used data from the the Giant Metrewave Radio Telescope [GMRT] in India in studying the properties of MACS J0416.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NRAO VLA
    NRAO/VLA

    Giant Metrewave Radio Telescope
    GMRT

    The Chandra data shows gas in the merging clusters with temperatures of millions of degrees. The optical data shows galaxies in the clusters and other, more distant, galaxies lying behind the clusters. Some of these background galaxies are highly distorted because of gravitational lensing, the bending of light by massive objects. This effect can also magnify the light from these objects, enabling astronomers to study background galaxies that would otherwise be too faint to detect. Finally, the structures in the radio data trace enormous shock waves and turbulence. The shocks are similar to sonic booms, generated by the mergers of the clusters.

    New results from multi-wavelength studies of MACS J0416 and MACS J0717, described in two separate papers, are included below.

    An open question for astronomers about MACS J0416 has been: are we seeing a collision in these clusters that is about to happen or one that has already taken place? Until recently, scientists have been unable to distinguish between these two explanations. Now, the combined data from these various telescopes is providing new answers.

    In MACS J0416 the dark matter (which leaves its gravitational imprint in the optical data) and the hot gas (detected by Chandra) line up well with each other. This suggests that the clusters have been caught before colliding. If the clusters were being observed after colliding the dark matter and hot gas should separate from each other, as seen in the famous colliding cluster system known as the Bullet Cluster.

    Bullet Cluster NASA Chandra NASA ESA Hubble
    Bullet Cluster. NASA/Chandra NASA/ESA Hubble

    The cluster in the upper left contains a compact core of hot gas, most easily seen in a specially processed image, and also shows evidence of a nearby cavity, or hole in the X-ray emitting gas. The presence of these structures also suggests that a major collision has not occurred recently, otherwise these features would likely have been disrupted. Finally, the lack of sharp structures in the radio image provides more evidence that a collision has not yet occurred.

    In the cluster located in the lower right, the observers have noted a sharp change in density on the southern edge of the cluster. This change in density is most likely caused by a collision between this cluster and a less massive structure located further to the lower right.

    In Jansky Very Large Array images of this cluster, seven gravitationally-lensed sources are observed, all point sources or sources that are barely larger than points. This makes MACS J0717 the cluster with the highest number of known lensed radio sources. Two of these lensed sources are also detected in the Chandra image. The authors are only aware of two other lensed X-ray sources behind a galaxy cluster.

    All of the lensed radio sources are galaxies located between 7.8 and 10.4 billion light years away from Earth. The brightness of the galaxies at radio wavelengths shows that they contain stars forming at high rates. Without the amplification by lensing, some of these radio sources would be too faint to detect with typical radio observations. The two lensed X-ray sources detected in the Chandra images are likely active galactic nuclei (AGN) at the center of galaxies. AGN are compact, luminous sources powered by gas heated to millions of degrees as it falls toward supermassive black holes. These two X-ray sources would have been detected without lensing but would have been two or three times fainter.

    The large arcs of radio emission in MACS J0717 are very different from those in MACS J0416 because of shock waves arising from the multiple collisions occurring in the former object. The X-ray emission in MACS J0717 has more clumps because there are four clusters violently colliding.

    Georgiana Ogrean, who was at Harvard-Smithsonian Center for Astrophysics while leading the work on MACS J0416 research, is currently at Stanford University. The paper describing these results was published in the October 20th, 2015 issue of the Astrophysical Journal and is available online. The research on MACS J0717 was led by Reinout van Weeren from the Harvard-Smithsonian Center for Astrophysics, and was published in the February 1st, 2016 issue of the Astrophysical Journal and is available online.

    See the full article here .

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

     
  • richardmitnick 9:28 pm on February 16, 2016 Permalink | Reply
    Tags: , , , NASA Chandra   

    From Chandra: “B3 0727+409: Glow from the Big Bang Allows Discovery of Distant Black Hole Jet” 

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    February 16, 2016
    No writer credit found

    Black Hole Jet B3 0727 409 Glow from the Big Bang Allows Discovery
    Credit X-ray: NASA/CXC/ISAS/A.Simionescu et al, Optical: DSS
    Release Date February 16, 2016

    A jet from a very distant black hole, called B3 0727+409, has been found using the Chandra X-ray Observatory. The light from this jet was emitted just 2.7 billion light years after the Big Bang when the Universe was only one fifth its current age. Jets in the early Universe such as this one give astronomers a way to probe the growth of black holes at a very early epoch. Typically, such distant jets are discovered in radio waves first, but not B3 0727+409 that was first found by Chandra.

    A jet from a very distant black hole being illuminated by the leftover glow from the Big Bang, known as the cosmic microwave background (CMB), has been found as described in our latest press release.

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    Astronomers using NASA’s Chandra X-ray Observatory discovered this faraway jet serendipitously when looking at another source in Chandra’s field of view.

    Jets in the early Universe such as this one, known as B3 0727+409, give astronomers a way to probe the growth of black holes at a very early epoch in the cosmos. The light from B3 0727+409 was emitted about 2.7 billion years after the Big Bang when the Universe was only about one fifth of its current age.

    This main panel graphic shows Chandra’s X-ray data that have been combined with an optical image from the [ESO]Digitized Sky Survey. (Note that the two sources near the center of the image do not represent a double source, but rather a coincidental alignment of the distant jet and a foreground galaxy.)

    Caltech Palomar  Samuel Oschin 48 inch Telescope
    Caltech Palomar  Samuel Oschin 48 inch Telescope Interior with Edwin Hubble
    UK Schmidt Telescope Exterior
    AAO UK Schmidt Telescope Interior
    Above, Caltech Palomar Samuel Oschin 48″ Schmidt telescope. Below, UK Schmidt telescope, both used in the DSS Survey.

    The inset shows more detail of the X-ray emission from the jet detected by Chandra. The length of the jet in 0727+409 is at least 300,000 light years. Many long jets emitted by supermassive black holes have been detected in the nearby Universe, but exactly how these jets give off X-rays has remained a matter of debate. In B3 0727+409, it appears that the CMB is being boosted to X-ray wavelengths.

    Scientists think that as the electrons in the jet fly from the black hole at close to the speed of light, they move through the sea of CMB radiation and collide with microwave photons. This boosts the energy of the photons up into the X-ray band to be detected by Chandra. If this is the case, it implies that the electrons in the B3 0727+409 jet must keep moving at nearly the speed of light for hundreds of thousands of light years.

    The significance of this discovery is heightened because astronomers essentially stumbled across this jet while observing a galaxy cluster in the field. Historically, such distant jets have been discovered in radio waves first, and then followed up with X-ray observations to look for high-energy emission. If bright X-ray jets can exist with very faint or undetected radio counterparts, it means that there could be many more of them out there because astronomers haven’t been systematically looking for them.

    A paper describing these results was published in the 2016 January 1st issue of The Astrophysical Journal Letters and is available online. The authors are Aurora Simionescu (Institute of Space and Astronautical Science, Kanagawa, Japan), Lukasz Stawarz (Jagiellonian University, Kraków, Poland), Yuto Ichinohe (Institute of Space and Astronautical Science, Kanagawa, Japan), Teddy Cheung (Naval Research Laboratory, Washington, DC), Marek Jamrozy (Jagiellonian University, Kraków, Poland), Aneta Siemiginowska (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA), Kouichi Hagino (Institute of Space and Astronautical Science, Kanagawa, Japan), Poshak Gandhi (University of Southampton, Southampton, UK) and Norbert Werner (Stanford University, Stanford, CA).

    See the full article here .

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

     
  • richardmitnick 3:53 pm on February 2, 2016 Permalink | Reply
    Tags: , , , Far Away, NASA Chandra, Pictor A: Blast from Black Hole in a Galaxy Far   

    From Chandra: “Pictor A: Blast from Black Hole in a Galaxy Far, Far Away” 

    NASA Chandra

    February 2, 2016
    Pictor A Blast from Black Hole in a Galaxy Far, Far Away
    Credit X-ray: NASA/CXC/Univ of Hertfordshire/M.Hardcastle et al., Radio: CSIRO/ATNF/ATCA
    Release Date February 2, 2016

    A giant jet spanning continuously for over 300,000 light years is seen blasting out of the galaxy Pictor A.

    A new composite image shows this jet in X-rays (blue) and radio waves (red). [see the original full article for more images.]

    In addition to the main jet, there is evidence for a jet moving in the opposite direction.

    Chandra observations at various times over a 15-year period provide new details of this impressive system.

    The Star Wars franchise has featured the fictitious “Death Star,” which can shoot powerful beams of radiation across space. The Universe, however, produces phenomena that often surpass what science fiction can conjure.

    The Pictor A galaxy is one such impressive object. This galaxy, located nearly 500 million light years from Earth, contains a supermassive black hole at its center. A huge amount of gravitational energy is released as material swirls towards the event horizon, the point of no return for infalling material. This energy produces an enormous beam, or jet, of particles traveling at nearly the speed of light into intergalactic space.

    To obtain images of this jet, scientists used NASA’s Chandra X-ray Observatory at various times over 15 years. Chandra’s X-ray data (blue) have been combined with radio data from the Australia Telescope Compact Array (red) in this new composite image.

    CSIRO Australia Compact Array
    Australia Telescope Compact Array

    By studying the details of the structure seen in both X-rays and radio waves, scientists seek to gain a deeper understanding of these huge collimated blasts.

    The jet [to the right] in Pictor A is the one that is closest to us. It displays continuous X-ray emission over a distance of 300,000 light years. By comparison, the entire Milky Way is about 100,000 light years in diameter. Because of its relative proximity and Chandra’s ability to make detailed X-ray images, scientists can look at detailed features in the jet and test ideas of how the X-ray emission is produced.

    In addition to the prominent jet seen pointing to the right in the image, researchers report evidence for another jet pointing in the opposite direction, known as a “counterjet”. While tentative evidence for this counterjet had been previously reported, these new Chandra data confirm its existence. The relative faintness of the counterjet compared to the jet is likely due to the motion of the counterjet away from the line of sight to the Earth.

    The labeled image shows the location of the supermassive black hole, the jet and the counterjet. Also labeled is a “radio lobe” where the jet is pushing into surrounding gas and a “hotspot” caused by shock waves – akin to sonic booms from a supersonic aircraft – near the tip of the jet.

    The detailed properties of the jet and counterjet observed with Chandra show that their X-ray emission likely comes from electrons spiraling around magnetic field lines, a process called synchrotron emission. In this case, the electrons must be continuously re-accelerated as they move out along the jet. How this occurs is not well understood

    The researchers ruled out a different mechanism for producing the jet’s X-ray emission. In that scenario, electrons flying away from the black hole in the jet at near the speed of light move through the sea of cosmic background radiation (CMB) left over from the hot early phase of the Universe after the Big Bang3.

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    When a fast-moving electron collides with one of these CMB photons, it can boost the photon’s energy up into the X-ray band.

    The X-ray brightness of the jet depends on the power in the beam of electrons and the intensity of the background radiation. The relative brightness of the X-rays coming from the jet and counterjet in Pictor A do not match what is expected in this process involving the CMB, and effectively eliminate it as the source of the X-ray production in the jet.

    A paper describing these results will be published in the Monthly Notices of the Royal Astronomical Society and is available online. The authors are Martin Hardcastle from the University of Hertfordshire in the UK, Emil Lenc from the University of Sydney in Australia, Mark Birkinshaw from the University of Bristol in the UK, Judith Croston from the University of Southampton in the UK, Joanna Goodger from the University of Hertfordshire, Herman Marshall from the Massachusetts Institute of Technology in Cambridge, MA, Eric Perlman from the Florida Institute of Technology, Aneta Siemiginowska from the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, Lukasz Stawarz from Jagiellonian University in Poland and Diana Worrall from the University of Bristol.

    See the full article here .

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

     
  • richardmitnick 4:48 pm on January 29, 2016 Permalink | Reply
    Tags: , , NASA Chandra, X-ray jet   

    From AAS NOVA: “Surprise Discovery of an X-Ray Jet” 

    AASNOVA

    American Astronomical Society

    29 January 2016
    Susanna Kohler

    Xray jet Chandra
    Chandra X-ray image of the quasar B3 0727+409. This high-redshift quasar jet is unusual in that there is very little radio emission associated with it. Very Large Array [VLA] radio observations are shown in green contours; click for the full view! [Simionescu et al. 2016]

    Accreting, supermassive black holes that reside at galactic centers can power enormous jets, bright enough to be observed from vast distances away. The recent discovery of such a jet in X-ray wavelengths, without an apparent radio counterpart, has interesting implications for our understanding of how these distant behemoths shine.

    An Excess of X-Rays

    Quasar B3 0727+409 was serendipitously discovered to host an X-ray jet when a group of scientists, led by Aurora Simionescu (Institute of Space and Astronautical Sciences of the Japan Aerospace Exploration Agency), was examining Chandra observations of another object.

    NASA Chandra Telescope
    NASA/Chandra

    NRAO VLA
    Karl V Jansky NRAO VLA

    The Chandra data reveal bright, compact, extended emission from the core of quasar B3 0727+409, with a projected length of ~100 kpc. There also appears to be further X-ray emission at a distance of ~280 kpc, which Simionescu and collaborators speculate may be the terminal hotspot of the jet.

    The quasar is located at a redshift of z=2.5 — which makes this jet one of only a few high-redshift X-ray jets known to date. But what makes it especially intriguing is that, though the authors searched through both recent and archival radio observations of the quasar, the only radio counterpart they could find was a small feature close to the quasar core (which may be a knot in the jet). Unlike what is typical of quasar jets, there was no significant additional radio emission coinciding with the rest of the X-ray jet.

    Making Jets Shine

    What does this mean? To answer this, we must consider one of the outstanding questions about quasar jets: what radiation processes dominate their emission? One process possibly contributing to the X-ray emission is inverse-Compton scattering of low-energy cosmic microwave background (CMB) photons off of the electrons in the jet; these photons can scatter up to X-ray energies.

    Interestingly, there’s a testable prediction associated with this mechanism. If this process dominates the X-ray emission of quasar jets, then the X-ray-to-radio flux ratio of the jet would increase with redshift as (1+z)4, due to the increased density of CMB photons at higher redshift.

    Thus far, our limited detections of high-redshift X-ray quasars have made it difficult to test this prediction, but quasar B3 0727+409 provides an extremely useful data point. When the authors model the radio-to-X-ray flux ratio for the jet, they find that it’s entirely consistent with the inverse-Compton scenario.

    This discovery suggests that the inverse-Compton mechanism may indeed be what dominates the X-ray radiation from jets like this one. And since our current observing strategies focus on Chandra follow-up of known bright radio jets, this could mean that there is an entire population of similar systems — with bright X-ray and faint radio emission — that we have missed!
    Citation

    A. Simionescu et al 2016 ApJ 816 L15. doi:10.3847/2041-8205/816/1/L15

    See the full article here .

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  • richardmitnick 4:12 pm on January 7, 2016 Permalink | Reply
    Tags: , , NASA Chandra, ,   

    From Hubble: “NASA’s Great Observatories Weigh Massive Young Galaxy Cluster” 

    NASA Hubble Telescope

    Hubble

    January 7, 2016
    CONTACT

    Megan Watzke
    Chandra X-ray Center, Cambridge, Massachusetts
    617-496-7998
    mwatzke@cfa.harvard.edu

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4514
    villard@stsci.edu

    Whitney Clavin
    Jet Propulsion Laboratory, Pasadena, California
    818-354-4673
    whitney.clavin@jpl.nasa.gov

    Mark Brodwin
    University of Missouri, Kansas City, Missouri
    brodwinm@umkc.edu

    Temp 1
    Hubble, Chandra, Spitzer Composite of Massive Galaxy Cluster IDCS J1426.5+3508

    Temp 2
    HST Image of Massive Galaxy Cluster IDCS J1426.5+3508

    Temp 3
    Compass and Scale Image of Massive Galaxy Cluster IDCS J1426.5+3508

    Astronomers have used data from three of NASA’s Great Observatories to make the most detailed study yet of an extremely massive young galaxy cluster. This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 trillion suns. This object has important implications for understanding how these megastructures formed and evolved early in the universe.

    The galaxy cluster, called IDCS J1426.5+3508 (IDCS 1426 for short), is so far away that the light detected is from when the universe was roughly a quarter of its current age. It is the most massive galaxy cluster detected at such an early age.

    First discovered by the Spitzer Space Telescope in 2012, IDCS 1426 was then observed using the Hubble Space Telescope and the Keck Observatory to determine its distance.

    NASA Spitzer Telescope
    NASA/Spitzer

    Keck Observatory
    Keck Observatory Interior
    Keck Observatory

    Observations from the Combined Array for Millimeter-wave Astronomy indicated it was extremely massive.

    Caltech Combined Array for Millimeter Astronomy
    Caltech/Combined Array for Millimeter-wave Astronomy

    New data from the Chandra X-ray Observatory confirm the galaxy cluster mass and show that about 90 percent of the mass of the cluster is in the form of dark matter, a mysterious substance detected so far only through its gravitational pull on normal matter composed of atoms.

    NASA Chandra Telescope
    NASA/Chandra

    “We are really pushing the boundaries with this discovery,” said Mark Brodwin of the University of Missouri at Kansas City, who led the study. “As one of the earliest massive structures to form in the universe, this cluster sets a high bar for theories that attempt to explain how clusters and galaxies evolve.”

    Galaxy clusters are the largest objects in the universe bound together by gravity. Because of their sheer size, scientists think it should take several billion years for them to form. The distance of IDCS J1426 means astronomers are observing it when the universe was only 3.8 billion years old, implying that the cluster is seen at a very young age.

    The data from Chandra reveal a bright knot of X-rays near the middle of the cluster, but not exactly at its center. This overdense core has been dislodged from the cluster center, possibly by a merger with another developing cluster 500 million years prior. Such a merger would cause the X-ray-emitting, hot gas to slosh around like wine in a glass that is tipped from side to side.

    “Mergers with other groups and clusters of galaxies should have been more common so early in the history of the universe,” said co-author Michael McDonald of the Massachusetts Institute of Technology in Cambridge, Massachusetts. “That appears to have played an important part in this young cluster’s rapid formation.”

    Aside from this cool core, the hot gas in the rest of the cluster is very smooth and symmetric. This is another indication that IDCS 1426 formed very rapidly. In addition, astronomers found possible evidence that the abundance of elements heavier than hydrogen and helium in the hot gas is unusually low. This suggests that this galaxy cluster might still be in the process of enriching its hot gas with these elements as supernovae create heavier elements and blast them out of individual galaxies.

    “The presence of this massive galaxy cluster in the early universe doesn’t upset our current understanding of cosmology,” said co-author of Anthony Gonzalez of the University of Florida in Gainesville, Florida. “It does, however, give us more information to work with as we refine our models.”

    Evidence for other massive galaxy clusters at early times has been found, but none of these matches IDCS 1426, with its combination of mass and youth. The mass determination used three independent methods: a measurement of the mass needed to confine the hot X-ray-emitting gas to the cluster, the imprint of the cluster’s gaseous mass on the cosmic microwave background radiation [CMB], and the observed distortions in the shapes of galaxies behind the cluster, which are caused by the bending of light from the galaxies by the gravity of the cluster.

    CMB Planck ESA
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    These results were presented at the 227th American Astronomical Society meeting being held in Kissimmee, Florida. A paper describing these results has been accepted for publication in The Astrophysical Journal and is available online. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington, D.C. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations. The Spitzer Space Telescope is managed by NASA’s Jet Propulsion Laboratory in Pasadena, California. The Spitzer Science Center at the California Institute of Technology in Pasadena conducts science operations. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

    Data Description:

    The HST data were taken from the following proposals: 11663 : M. Brodwin (University of Missouri, Kansas City), P. Eisenhardt (JPL), A. Stanford (UC Davis/LLNL), D. Stern (JPL), L. Moustakas (JPL), A. Dey (NOAO), B. Jannuzi (University of Arizona/NOAO), and A. Gonzalez (University of Florida, Gainesville);

    12203: A. Stanford (UC Davis/LLNL), M. Brodwin (University of Missouri, Kansas City), A. Gonzalez (University of Florida, Gainesville), A. Dey (NOAO), D. Stern (JPL), G. Zeimann (Penn State University), and P. Eisenhardt and L. Moustakas (JPL);

    and 12994: A. Gonzalez (University of Florida, Gainesville), M. Brodwin (University of Missouri, Kansas City), A. Stanford (UC Davis/LLNL), J. Rhodes and D. Stern (JPL), P. Eisenhardt (JPL), C. Fedeli (University of Florida), G. Zeimann (Penn State University), A. Dey (NOAO), and D. Marrone (University of Arizona).

    The science team includes M. Brodwin (University of Missouri, Kansas City), M. McDonald (MIT), A. Gonzalez (University of Florida, Gainesville), A. Stanford (UC Davis/LLNL), P. Eisenhardt and D. Stern (JPL), and G. Zeimann (Penn State University).
    Instruments/Filters:
    ACS/WFC F606W (V)
    ACS//WFC F814W(I)
    WFC3/IR F160W (H)

    NASA Hubble ACS
    ACS

    NASA Hubble WFC3
    WFC3

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 5:48 pm on January 5, 2016 Permalink | Reply
    Tags: , , NASA Chandra, NGC 5195 Galaxy   

    From Chandra- “NGC 5195: NASA’s Chandra Finds Supermassive Black Hole Burping Nearby” 

    NASA Chandra

    January 5, 2016
    No writer credit found

    Temp 1
    Credit X-ray: NASA/CXC/Univ of Texas/E.Schlegel et al; Optical: NASA/STScI
    Release Date January 5, 2016

    One of the nearest supermassive black holes to Earth with active powerful outbursts has been discovered.

    Such outbursts are part of the “feedback” process that is important to the evolution of the black hole and its host galaxy.

    Evidence for these eruptions was found with the Chandra X-ray Observatory in the galaxy NGC 5195.

    Two arcs in the X-ray data suggest separate eruptions from the black hole occurred millions of years ago.

    Astronomers have used NASA’s Chandra X-ray Observatory to discover one of the nearest supermassive black holes to Earth that is currently undergoing powerful outbursts, as described in our latest press release. This galactic burping was found in the Messier 51 galaxy, which is located about 26 million light years from Earth and, contains a large spiral galaxy NGC 5194 (also known by its nickname of the “Whirlpool”), merging with a smaller companion galaxy NGC 5195.

    This main panel of this graphic shows M51 in visible light data from the Hubble Space Telescope (red, green, and blue).

    NASA Hubble Telescope
    NASA/ESA Hubble

    The box at the top of the image outlines the field of view by Chandra in the latest study, which focuses on the smaller component of M51, NGC 5195.

    The inset to the right shows the details of the Chandra data (blue) of this region. Researchers found a pair of arcs in X-ray emission close to the center of the galaxy, which they interpret as two outbursts from the galaxy’s supermassive black hole (mouse over annotated image for additional information). The authors estimate that it took about one to three million years for the inner arc to reach its current position, and three to six million years for the outer arc.

    Temp 1
    X-ray close-up

    Just outside the outer X-ray arc is a slender region of hydrogen emission detected in an optical image. This suggests that the X-ray emitting gas has “snow-plowed” or swept-up the hydrogen gas from the center of the galaxy. This is a clear case where a supermassive black hole is affecting its host galaxy, in a phenomenon that astronomers called “feedback.”

    This arc of hydrogen gas contains what appears to be two or three small “HII regions.” An HII (pronounced “H-two”) region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms (HI) to form clouds of ionized hydrogen (HII). This suggests that the outer arc has plowed up enough material to trigger the formation of new stars.

    The outbursts of the supermassive black hole in NGC 5195 may have been triggered by the interaction of this galaxy with the large spiral galaxy in M51, causing gas to be disrupted and then funneled down towards the black hole.

    These results were presented at the 227th meeting of the American Astronomical Society meeting in Kissimmee, Florida. They are also in a paper submitted to The Astrophysical Journal and the authors are Eric Schlegel (University of Texas at San Antonio), Christine Jones (Harvard-Smithsonian Center for Astrophysics), Marie Marachek (CfA), and Laura Vega (Fisk University and Vanderbilt University Bridge Program).

    See the full article here .

    Another view of NGC 5195, this from NASA/ESA Hubble
    3
    A Hubble Space Telescope (HST) image of Messier 51. M51A (the Whirlpool Galaxy) is the spiral galaxy on the left. NGC 5195 is the galaxy in the top right corner. Credit:HST/STScI/AURA/NASA/ESA.

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

     
  • richardmitnick 2:31 pm on December 25, 2015 Permalink | Reply
    Tags: , , , NASA Chandra   

    From CfA: “Magnetic Fields in Powerful Radio Jets” 

    Smithsonian Astrophysical Observatory
    Smithsonian Astrophysical Observatory

    December 25, 2015
    No Writer Credit

    1
    X-ray jets from the galaxy Pictoris A. The greyscale image was taken by the Chandra X-ray Observatory and reveals the detailed X-ray structure of the jets, which extend over nearly one million light-years. The red contours show the radio emission. Astronomers analyzing these and other data have concluded that the X-ray emission is produced by rapidly moving charged particles in magnetic fields. NASA/Chandra, Hardcastle et al.

    Super-massive black holes at the centers of galaxies can spawn tremendous bipolar jets when matter in the vicinity forms a hot, accreting disk around the black hole. The rapidly moving charged particles in the jets radiate when they are deflected by magnetic fields; these jets were discovered at radio wavelengths several decades ago. In the most dramatic cases, the energetic particles move at speeds close to the speed of light and extend over hundreds of thousands of light-years, well beyond the visible boundaries of the galaxy. The physical processes that drive these jets and cause them to radiate are among the most important outstanding problems of modern astrophysics.

    One of the most significant and unexpected discoveries of the Chandra X-ray Observatory was that bright X-rays are also emitted by these jets.

    NASA Chandra Telescope
    NASA Chandra

    The X-rays are also produced by the acceleration of charged particles, at least according to some models, but there are other possible mechanisms as well. Fast-moving particles can scatter background light, boosting it into the X-ray band. Alternatively, shocks can generate X-ray emission (or at least a significant portion of it), either as the jets interact with stellar winds and interstellar medium or, within the jet, as a consequence of jet variability, instability, turbulence, or other phenomena.

    2
    Original NASA description: The Hubble Space Telescope imaged this view in February 1995. The arcing, graceful structure is actually a bow shock about half a light-year across, created from the wind from the star L.L. Orionis colliding with the Orion Nebula flow.
    Date February 1995
    Source NASA

    NASA Hubble Telescope
    NASA/ESA Hubble

    CfA astronomer Aneta Siemiginowska and her colleagues have studied the bright radio jet galaxy Pictoris A, located almost five hundred million light-years away, using very deep Chandra measurements – the observations used an accumulated total of over four days of time, spread over a fourteen year period. These data enabled the first detailed analysis of the spectral character of the emission all along the jets. The emission turns out to be remarkably uniform everywhere, something that is extremely unlikely if scattering were responsible, but which is a natural consequence of the magnetic field process. The scientists therefore reject the scattering model in favor of the latter. However, the jets do have within them many small clumps, internal structures, and lobes. Shocks and/or scattering are possible explanations for the emission in some of these structures. Although these new results represent some dramatic improvements in our understanding of Pic A, high-resolution radio measurements of a large sample of similar jets are now needed to refine and extend the models. Large-scale X-ray jets, for example, have been also detected in very distant quasars. The results from Pic A, together with future Chandra observations, will help astronomers determine the extent to which these distant jets also rely on the same processes, or if they invoke other ones.

    Reference(s):

    “Deep Chandra Observations of Pictor A,” M.J. Hardcastle, E. Lenc, M. Birkinshaw, J.H. Croston, J.L. Goodger, H.L. Marshall, E.S. Perlman, A. Siemiginowska, Ł. Stawarz, and D.M. Worrall, MNRAS 2015 (in press).

    See the full article here .

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    About CfA

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy. The long relationship between the two organizations, which began when the SAO moved its headquarters to Cambridge in 1955, was formalized by the establishment of a joint center in 1973. The CfA’s history of accomplishments in astronomy and astrophysics is reflected in a wide range of awards and prizes received by individual CfA scientists.

    Today, some 300 Smithsonian and Harvard scientists cooperate in broad programs of astrophysical research supported by Federal appropriations and University funds as well as contracts and grants from government agencies. These scientific investigations, touching on almost all major topics in astronomy, are organized into the following divisions, scientific departments and service groups.

     
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