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  • richardmitnick 10:22 am on February 14, 2018 Permalink | Reply
    Tags: , , , , , Manu Garcia‎, Messier 33   

    From ESO via Manu: “Triangulum Galaxy Snapped by VST” 2014 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    ESO 50 Large

    European Southern Observatory

    6 August 2014

    Contacts
    J. Miguel Mas Hesse
    Center for Astrobiology (CSIC-INTA)
    Madrid, Spain
    Tel .: (+34) 918 131 196
    Email: mm@cab.inta-csic.es

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

    1
    The VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile has captured a beautifully detailed image of the galaxy Messier 33. This nearby spiral, the second closest large galaxy to our own galaxy, the Milky Way, is packed with bright star clusters, and clouds of gas and dust. The new picture is amongst the most detailed wide-field views of this object ever taken and shows the many glowing red gas clouds in the spiral arms with particular clarity.

    ESO VST interior

    Messier 33, otherwise known as NGC 598, is located about three million light-years away in the small northern constellation of Triangulum (The Triangle). Often known as the Triangulum Galaxy it was observed by the French comet hunter Charles Messier in August 1764, who listed it as number 33 in his famous list of prominent nebulae and star clusters. However, he was not the first to record the spiral galaxy; it was probably first documented by the Sicilian astronomer Giovanni Battista Hodierna around 100 years earlier.

    Although the Triangulum Galaxy lies in the northern sky, it is just visible from the southern vantage point of ESO’s Paranal Observatory in Chile. However, it does not rise very high in the sky. This image was taken by the VLT Survey Telescope (VST), a state-of-the-art 2.6-metre survey telescope with a field of view that is twice as broad as the full Moon. This picture was created from many individual exposures, including some taken through a filter passing just the light from glowing hydrogen, which make the red gas clouds in the galaxies spiral arms especially prominent.

    Among the many star formation regions in Messier 33’s spiral arms, the giant nebula NGC 604 stands out. With a diameter of nearly 1500 light-years, this is one of the largest nearby emission nebulae known. It stretches over an area 40 times the size of the visible portion of the much more famous — and much closer — Orion Nebula.

    The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, which includes the Milky Way, the Andromeda Galaxy, and about 50 other smaller galaxies.

    Local Group. Andrew Z. Colvin 3 March 2011

    Milky Way NASA/JPL-Caltech /ESO R. Hurt

    Andromeda Galaxy Adam Evans

    On an extremely clear, dark night, this galaxy is just visible with the unaided eye, and is considered to be the most distant celestial object visible without any optical help. Viewing conditions for the very patient are only set to improve in the long-term: the galaxy is approaching our own at a speed of about 100 000 kilometres per hour.

    A closer look at this beautiful new picture not only allows a very detailed inspection of the star-forming spiral arms of the galaxy, but also reveals the very rich scenery of the more distant galaxies scattered behind the myriad stars and glowing clouds of NGC 598.

    2
    Wide – field image of the galaxy Messier 33. Credit: ESO / DSS2, Davide De Martin.

    See the full article here .

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

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

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

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

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

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

    ESO ExTrA telescopes at Cerro LaSilla at an altitude of 2400 metres

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  • richardmitnick 3:00 pm on February 1, 2018 Permalink | Reply
    Tags: , , , , , Manu Garcia‎   

    From Chandra via Manu: “NASA’s Chandra Turns up Black Hole Bonanza in Galaxy Next Door” 2013 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NASA Chandra Banner

    NASA Chandra Telescope

    NASA Chandra

    June 12, 2013

    Media contacts:
    J.D. Harrington
    Headquarters, Washington
    202-358-5241
    j.d.harrington@nasa.gov

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

    1
    Credit: X-ray (NASA / CXC / SAO / R.Barnard, Z.Lee et al.), Optical (NOAO / AURA / NSF / REU Prog./B.Schoening, V.Harvey; Discover Fndn./CAHA/ OAUV / DSA / V.Peris).

    2
    The Andromeda galaxy in optical vision box for the black hole candidates captured X – ray by Chandra.

    3
    Chandra image near the core of Messier 31 with X – ray sources in red circles.

    Using data from NASA’s Chandra X-ray Observatory, astronomers have discovered an unprecedented bonanza of black holes in the Andromeda Galaxy, one of the nearest galaxies to the Milky Way.

    Using more than 150 Chandra observations, spread over 13 years, researchers identified 26 black hole candidates, the largest number to date, in a galaxy outside our own. Many consider Andromeda to be a sister galaxy to the Milky Way. The two ultimately will collide, several billion years from now.

    “While we are excited to find so many black holes in Andromeda, we think it’s just the tip of the iceberg,” said Robin Barnard of Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., and lead author of a new paper describing these results. “Most black holes won’t have close companions and will be invisible to us.”

    The black hole candidates belong to the stellar mass category, meaning they formed in the death throes of very massive stars and typically have masses five to 10 times that of our sun. Astronomers can detect these otherwise invisible objects as material is pulled from a companion star and heated up to produce radiation before it disappears into the black hole.

    The first step in identifying these black holes was to make sure they were stellar mass systems in the Andromeda Galaxy itself, rather than supermassive black holes at the hearts of more distant galaxies. To do this, the researchers used a new technique that draws on information about the brightness and variability of the X-ray sources in the Chandra data. In short, the stellar mass systems change much more quickly than the supermassive black holes.

    To classify those Andromeda systems as black holes, astronomers observed that these X-ray sources had special characteristics: that is, they were brighter than a certain high level of X-rays and also had a particular X-ray color. Sources containing neutron stars, the dense cores of dead stars that would be the alternate explanation for these observations, do not show both of these features simultaneously. But sources containing black holes do.

    The European Space Agency’s XMM-Newton X-ray observatory added crucial support for this work by providing X-ray spectra, the distribution of X-rays with energy, for some of the black hole candidates. The spectra are important information that helps determine the nature of these objects.

    ESA/XMM Newton X-ray telescope

    “By observing in snapshots covering more than a dozen years, we are able to build up a uniquely useful view of M31,” said co-author Michael Garcia, also of CfA. “The resulting very long exposure allows us to test if individual sources are black holes or neutron stars.”

    The research group previously identified nine black hole candidates within the region covered by the Chandra data, and the present results increase the total to 35. Eight of these are associated with globular clusters, the ancient concentrations of stars distributed in a spherical pattern about the center of the galaxy. This also differentiates Andromeda from the Milky Way as astronomers have yet to find a similar black hole in one of the Milky Way’s globular clusters.

    Seven of these black hole candidates are within 1,000 light-years of the Andromeda Galaxy’s center. That is more than the number of black hole candidates with similar properties located near the center of our own galaxy. This is not a surprise to astronomers because the bulge of stars in the middle of Andromeda is bigger, allowing more black holes to form.

    “When it comes to finding black holes in the central region of a galaxy, it is indeed the case where bigger is better,” said co-author Stephen Murray of Johns Hopkins University and CfA. “In the case of Andromeda we have a bigger bulge and a bigger supermassive black hole than in the Milky Way, so we expect more smaller black holes are made there as well.”

    This new work confirms predictions made earlier in the Chandra mission about the properties of X-ray sources near the center of M31. Earlier research by Rasmus Voss and Marat Gilfanov of the Max Planck Institute for Astrophysics in Garching, Germany, used Chandra to show there was an unusually large number of X-ray sources near the center of M31. They predicted most of these extra X-ray sources would contain black holes that had encountered and captured low mass stars. This new detection of seven black hole candidates close to the center of M31 gives strong support to these claims.

    “We are particularly excited to see so many black hole candidates this close to the center, because we expected to see them and have been searching for years,” said Barnard.

    These results will be published in the June 20 issue of The Astrophysical Journal. Many of the Andromeda observations were made within Chandra’s Guaranteed Time Observer program.

    See the full article here .

    Please help promote STEM in your local schools.

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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 9:44 am on January 4, 2018 Permalink | Reply
    Tags: , , , , , Manu Garcia‎,   

    From Hubble via Manu: “Hubble Reveals Stellar Fireworks in ‘Skyrocket’ Galaxy” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    Thanks, Manu

    NASA/ESA Hubble Telescope

    28 June 2016 [Found by Manu Garcia at IAC.]

    Donna Weaver
    Space Telescope Science Institute, Baltimore, Maryland
    410-338-4493
    dweaver@stsci.edu

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

    Debra Elmegreen
    Vassar College, Poughkeepsie, New York
    elmegreen@vassar.edu

    1
    As we celebrate the Fourth of July by watching dazzling fireworks shows, another kind of fireworks display is taking place in a small, nearby galaxy.

    A stellar fireworks show is lighting up one end of the diminutive galaxy Kiso 5639. The dwarf galaxy is shaped like a flattened pancake, but because it is tilted edge-on, it resembles a skyrocket, with a brilliant blazing head and a long, star-studded tail. Kiso 5639 is a rare, nearby example of elongated galaxies seen in abundance in the early universe. Astronomers suggest that the frenzied star birth is sparked by intergalactic gas raining on one end of the galaxy as it drifts through space.

    Fireworks shows are not just confined to Earth’s skies. NASA’s Hubble Space Telescope has captured a spectacular fireworks display in a small, nearby galaxy, which resembles a July 4th skyrocket.

    A firestorm of star birth is lighting up one end of the diminutive galaxy Kiso 5639. The dwarf galaxy is shaped like a flattened pancake, but because it is tilted edge-on, it resembles a skyrocket, with a brilliant blazing head and a long, star-studded tail.

    Kiso 5639 is a rare, nearby example of elongated galaxies that occur in abundance at larger distances, where we observe the universe during earlier epochs. Astronomers suggest that the frenzied star birth is sparked by intergalactic gas raining on one end of the galaxy as it drifts through space.

    “I think Kiso 5639 is a beautiful, up-close example of what must have been common long ago,” said lead researcher Debra Elmegreen of Vassar College, in Poughkeepsie, New York. “The current thinking is that galaxies in the early universe grow from accreting gas from the surrounding neighborhood. It’s a stage that galaxies, including our Milky Way, must go through as they are growing up.”

    Observations of the early universe, such as Hubble’s Ultra Deep Field, reveal that about 10 percent of all galaxies have these elongated shapes, and are collectively called “tadpoles.” But studies of the nearby universe have turned up only a few of these unusual galaxies, including Kiso 5639. The development of the nearby star-making tadpole galaxies, however, has lagged behind that of their peers, which have spent billions of years building themselves up into many of the spiral galaxies seen today.

    Elmegreen used Hubble’s Wide Field Planetary Camera 3 to conduct a detailed imaging study of Kiso 5639.

    Wide Field Camera 3 (WFC3) being tested.

    The images in different filters reveal information about an object by dissecting its light into its component colors. Hubble’s crisp resolution helped Elmegreen and her team analyze the giant star-forming clumps in Kiso 5639 and determine the masses and ages of the star clusters.

    The international team of researchers selected Kiso 5639 from a spectroscopic survey of 10 nearby tadpole galaxies, observed with the Grand Canary Telescope in La Palma, Spain, by J. Sánchez Almeida and collaborators at the Instituto de Astrofísica de Canarias. The observations revealed that in most of those galaxies, including Kiso 5639, the gas composition is not uniform.

    The bright gas in the galaxy’s head contains fewer heavier elements (collectively called “metals”), such as carbon and oxygen, than the rest of the galaxy. Stars consist mainly of hydrogen and helium, but cook up other “heavier” elements. When the stars die, they release their heavy elements and enrich the surrounding gas.

    “The metallicity suggests that there has to be rather pure gas, composed mostly of hydrogen, coming into the star-forming part of the galaxy, because intergalactic space contains more pristine hydrogen-rich gas,” Elmegreen explained. “Otherwise, the starburst region should be as rich in heavy elements as the rest of the galaxy.”

    Hubble offers a detailed view of the galaxy’s star-making frenzy. The telescope uncovered several dozen clusters of stars in the galaxy’s star-forming head, which spans 2,700 light-years across. These clusters have an average age of less than 1 million years and masses that are three to six times larger than those in the rest of the galaxy. Other star formation is taking place throughout the galaxy but on a much smaller scale. Star clusters in the rest of the galaxy are between several million to a few billion years old.

    “There is much more star formation going on in the head than what you would expect in such a tiny galaxy,” said team member Bruce Elmegreen of IBM’s Thomas J. Watson Research Center, in Yorktown Heights, New York. “And we think the star formation is triggered by the ongoing accretion of metal-poor gas onto a part of an otherwise quiescent dwarf galaxy.”

    Hubble also revealed giant holes peppered throughout the galaxy’s starburst head. These cavities give the galaxy’s head a Swiss-cheese appearance because numerous supernova detonations – like firework aerial bursts – have carved out holes of rarified superheated gas.

    The galaxy, located 82 million light-years away, has taken billions of years to develop because it has been drifting through an isolated “desert” in the universe, devoid of much gas.

    What triggered the starburst in such a backwater galaxy? Based on simulations by Daniel Ceverino of the Center for Astronomy at Heidelberg University in Germany, and other team members, the observations suggest that less than 1 million years ago, Kiso 5639’s leading edge encountered a filament of gas. The filament dropped a large clump of matter onto the galaxy, stoking the vigorous star birth.

    Debra Elmegreen expects that in the future other parts of the galaxy will join in the star-making fireworks show. “Galaxies rotate, and as Kiso 5639 continues to spin, another part of the galaxy may receive an infusion of new gas from this filament, instigating another round of star birth,” she said.

    The team’s results have been accepted for publication in The Astrophysical Journal.

    Other team members include Casiana Muñoz-Tuñón and Mercedes Filho (Instituto de Astrofísica de Canarias, Canary Islands), Jairo Mendez-Abreu (University of St. Andrews, United Kingdom), John Gallagher (University of Wisconsin-Madison), and Marc Rafelski (NASA Goddard Space Flight Center, Greenbelt, Maryland).

    Credits

    Credit: NASA, ESA, and D. Elmegreen (Vassar College), B. Elmegreen (IBM’s Thomas J. Watson Research Center), J. Sánchez Almeida, C. Muñoz-Tuñón, and M. Filho (Instituto de Astrofísica de Canarias), J. Mendez-Abreu (University of St. Andrews), J. Gallagher (University of Wisconsin-Madison), M. Rafelski (NASA Goddard Space Flight Center), and D. Ceverino (Center for Astronomy at Heidelberg University)

    See the full article here .

    Please help promote STEM in your local schools.

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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 8:51 am on December 22, 2017 Permalink | Reply
    Tags: , , , , Manu Garcia‎, , New Study Finds 'Winking' Star May Be Devouring Wrecked Planets, RZ Piscium   

    From Goddard via Manu: “New Study Finds ‘Winking’ Star May Be Devouring Wrecked Planets” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    Dec. 21, 2017

    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A team of U.S. astronomers studying the star RZ Piscium has found evidence suggesting its strange, unpredictable dimming episodes may be caused by vast orbiting clouds of gas and dust, the remains of one or more destroyed planets.

    1
    RZ Piscium, located in the constellation Pisces, is surrounded by huge dust clouds that appear to be the remains of one or more destroyed planets. Photo: NASA

    “Our observations show there are massive blobs of dust and gas that occasionally block the star’s light and are probably spiraling into it,” said Kristina Punzi, a doctoral student at the Rochester Institute of Technology (RIT) in New York and lead author of a paper describing the findings. “Although there could be other explanations, we suggest this material may have been produced by the break-up of massive orbiting bodies near the star.”


    Zoom into RZ Piscium, a star about 550 light-years away that undergoes erratic dips in brightness. This animation illustrates one possible interpretation of the system, with a giant planet near the star slowly dissolving. Gas and dust intermittently stream away from the planet, and these clouds occasionally eclipse the star as we view it from Earth. Credits: NASA’s Goddard Space Flight Center/CI Lab.

    RZ Piscium is located about 550 light-years away in the constellation Pisces. During its erratic dimming episodes, which can last as long as two days, the star becomes as much as 10 times fainter. It produces far more energy at infrared wavelengths than emitted by stars like our Sun, which indicates the star is surrounded by a disk of warm dust. In fact, about 8 percent of its total luminosity is in the infrared, a level matched by only a few of the thousands of nearby stars studied over the past 40 years. This implies enormous quantities of dust.

    These and other observations led some astronomers to conclude that RZ Piscium is a young Sun-like star surrounded by a dense asteroid belt, where frequent collisions grind the rocks to dust.

    But the evidence was far from clear. An alternative view suggests the star is instead somewhat older than our Sun and just beginning its transition into the red giant stage. A dusty disk from the star’s youth would have dispersed after a few million years, so astronomers needed another source of dust to account for the star’s infrared glow. Because the aging star is growing larger, it would doom any planets in close orbits, and their destruction could provide the necessary dust.

    So which is it, a young star with a debris disk or a planet-smashing stellar senior? According to the research by Punzi and her colleagues, RZ Piscium is a bit of both.

    The team investigated the star using the European Space Agency’s (ESA) XMM-Newton satellite, the Shane 3-meter telescope at Lick Observatory in California and the 10-meter Keck I telescope at W. M. Keck Observatory in Hawaii.

    ESA/XMM Newton X-ray telescope

    The UCO Lick C. Donald Shane telescope is a 120-inch (3.0-meter) reflecting telescope located at the Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)

    UCSC Lick Observatory, Mt Hamilton, in San Jose, California, Altitude 1,283 m (4,209 ft)


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    Young stars are often prodigious X-ray sources. Thanks to 11 hours of XMM-Newton observations, Punzi’s team shows that RZ Piscium is, too. Its total X-ray output is roughly 1,000 times greater than our Sun’s, essentially clinching the case for stellar youth.

    The team’s ground-based observations revealed the star’s surface temperature to be about 9,600 degrees Fahrenheit (5,330 degrees Celsius), only slightly cooler than the Sun’s. They also show the star is enriched in the tell-tale element lithium, which is slowly destroyed by nuclear reactions inside stars.

    “The amount of lithium in a star’s surface declines as it ages, so it serves as a clock that allows us to estimate the elapsed time since a star’s birth,” said co-author Joel Kastner, director of RIT’s Laboratory for Multiwavelength Astrophysics. “Our lithium measurement for RZ Piscium is typical for a star of its surface temperature that is about 30 to 50 million years old.”

    So while the star is young, it’s actually too old to be surrounded by so much gas and dust. “Most Sun-like stars have lost their planet-forming disks within a few million years of their birth,” said team member Ben Zuckerman, an astronomy professor at the University of California, Los Angeles. “The fact that RZ Piscium hosts so much gas and dust after tens of millions of years means it’s probably destroying, rather than building, planets.”

    Ground-based observations also probed the star’s environment, capturing evidence that the dust is accompanied by substantial amounts of gas. Based on the temperature of the dust, around 450 degrees F (230 degrees C), the researchers think most of the debris is orbiting about 30 million miles (50 million kilometers) from the star.

    “While we think the bulk of this debris is about as close to the star as the planet Mercury ever gets to our Sun, the measurements also show variable and rapidly moving emission and absorption from hydrogen-rich gas,” said co-author Carl Melis, an associate research scientist at the University of California, San Diego. “Our measurements provide evidence that material is both falling inward toward the star and also flowing outward.”

    A paper reporting the findings was published Thurs., Dec. 21, in The Astronomical Journal.

    The best explanation that accounts for all of the available data, say the researchers, is that the star is encircled by debris representing the aftermath of a disaster of planetary proportions. It’s possible the star’s tides may be stripping material from a close substellar companion or giant planet, producing intermittent streams of gas and dust, or that the companion is already completely dissolved. Another possibility is that one or more massive gas-rich planets in the system underwent a catastrophic collision in the astronomically recent past.

    ESA’s XMM-Newton observatory was launched in December 1999 from Kourou, French Guiana. NASA funded elements of the XMM-Newton instrument package and provides the NASA Guest Observer Facility at Goddard, which supports use of the observatory by U.S. astronomers.

    See the full Goddard article here.
    See Manu Garcia’s full article here. Look near the top for the language translator.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


    NASA/Goddard Campus

     
  • richardmitnick 12:25 pm on December 17, 2017 Permalink | Reply
    Tags: a fusion of galaxies, ARP 273, , , , , Manu Garcia‎,   

    From Manu Garcia for Hubble: “ARP 273, a fusion of galaxies” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NASA Hubble contacts
    Oli Usher
    Hubble/ESA
    Garching, Germany
    Tel: +49-89-3200-6855
    ousher@eso.org

    Ray Villard
    Space Telescope Science Institute
    Baltimore, USA
    Tel: +1-410-338-4514
    villard@stsci.edu

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    1
    UGC 1810 is located on top of the image, UGC 1813 at the bottom.
    This Hubble image is a composite of data taken with three separate WFC3 that allow a wide range of wavelengths covering the blue and red ultraviolet portions of the spectrum filter. Credits: NASA, ESA, and equipment Hubble Heritage (STScI / AURA)

    In celebration of the 21st anniversary of the deployment of the Hubble Space Telescope in space, astronomers at the Space Telescope Institute of Science in Baltimore, Maryland, led the Hubble eye to an especially photogenic group of interacting galaxies called Arp 273.

    The largest of the spirals, known as UGC 1810 , has a disc which is distorted in a way tidalmente rose by the gravitational pull of the tide of the companion galaxy below it, known as UGC 1813 . A strip of blue jewels across the top is the combined light from clusters of intensely bright and hot blue stars. These massive stars glow in ultraviolet light.

    The smallest and most fellow at the border shows distinct signs of intense star formation at its nucleus, perhaps triggered by the encounter with the companion galaxy.

    A number of unusual spiral patterns in the large galaxy is a telltale sign of interaction. The large external arm partially shown as a ring, a feature seen when interacting galaxies actually pass each other. This suggests that the smaller companion sank deep, but off-center, through UGC 1810 . The inner set of spiral arms is highly distorted the plane with one arm going behind the bulge and returns on the other side. It is not known exactly how these two spiral patterns are connected.

    A mini-spiral may be visible in the spiral arms of UGC 1810 in the upper right. It is remarkable how the outer spiral arm changes shape as it passes this third galaxy, smooth with many old stars (reddish) back and clumpy and extremely blue on the other. The fairly regular spacing forming knots blue stars fits what is seen in the spiral arms of other galaxies and is predictable based on the instabilities in the gas in the arm.

    2
    Hubble’s WFC3

    The largest pair galaxy UGC 1810 – 1813 UGC has a mass which is approximately five times that of the smaller galaxy. In unequal pairs like this, the relatively rapid passage of a companion galaxy produces unbalanced or asymmetric structure in the primary coil. Also in such matches, the starburst activity typically begins in the smaller galaxies rather than the main galaxies. These effects could be due to the fact that the smaller galaxies have consumed less gas in its core, where new stars are born.

    Arp 273 lies in the constellation Andromeda and is about 300 million light years away from Earth. The image shows a tenuous tidal bridge of material between the two galaxies that are separated by tens of thousands of light years apart.

    The interaction was visualized on 17 December 2010 with the Wide Field Camera 3, Hubble (WFC3), Wide Field Camera 3.

    Published in Hubble on 20 April 2011.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    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 10:08 am on December 17, 2017 Permalink | Reply
    Tags: , , , , Manu Garcia‎,   

    From Hubble via Manu: “Galaxies gone wild!” 24 April 2008 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    24 April 2008
    Aaron Evans
    Department of Astronomy
    University of Virginia, Charlottesville, USA
    E-mail: aaron.evans@stonybrook.edu

    Lars Lindberg Christensen
    Hubble/ESA, Garching, Germany
    Tel: +49-(0)89-3200-6306
    Cellular: +49-(0)173-3872-621
    E-mail: lars@eso.org

    Ray Villard
    Space Telescope Science Institute, Baltimore, USA
    Tel: +1-410-338-4514
    E-mail: villard@stsci.edu

    1
    Fifty nine new images of colliding galaxies make up the largest collection of Hubble images ever released together. As this astonishing Hubble atlas of interacting galaxies illustrates, galaxy collisions produce a remarkable variety of intricate structures.

    Interacting galaxies are found throughout the Universe, sometimes as dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that result in new galaxies. A series of 59 new images of colliding galaxies has been released from the several terabytes of archived raw images from the NASA/ESA Hubble Space Telescope to mark the 18th anniversary of the telescope’s launch. This is the largest collection of Hubble images ever released to the public simultaneously.

    Galaxy mergers, which were more common in the early Universe than they are today, are thought to be one of the main driving forces for cosmic evolution, turning on quasars, sparking frenetic star births and explosive stellar deaths. Even apparently isolated galaxies will show signs in their internal structure that they have experienced one or more mergers in their past. Each of the various merging galaxies in this series of images is a snapshot of a different instant in the long interaction process.

    Our own Milky Way contains the debris of the many smaller galaxies it has encountered and devoured in the past, and it is currently absorbing the Sagittarius dwarf elliptical galaxy.

    Credits: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)

    In turn, it looks as if our Milky Way will be subsumed into its giant neighbour, the Andromeda galaxy, resulting in an elliptical galaxy, dubbed “Milkomeda”, the new home for the Earth, the Sun and the rest of the Solar System in about two billion years time. The two galaxies are currently rushing towards each other at approximately 500,000 kilometres per hour.

    Andromeda Galaxy Messier 31 with Messier32 -a satellite galaxy copyright Terry Hancock.

    Cutting-edge observations and sophisticated computer models, such as those pioneered by the two Estonian brothers Alar Toomre and Juri Toomre in the 1970s, demonstrate that galaxy collisions are far more common than previously thought.

    2
    ESO 593-8 is an impressive pair of interacting galaxies with a feather-like galaxy crossing a companion galaxy. The two components will probably merge to form a single galaxy in the future. The pair is adorned with a number of bright blue star clusters. ESO 593-8 is located in the constellation of Sagittarius, the Archer, some 650 million light-years away from Earth.
    This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on 24th April 2008. Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University)

    Interactions are slow stately affairs, despite the typically high relative speeds of the interacting galaxies, taking hundreds of millions of years to complete. The interactions usually follow the same progression, and are driven by the tidal pull of gravity. Actual collisions between stars are rare as so much of a galaxy is simply empty space, but as the gravitational webs linking the stars in each galaxy begin to mesh, strong tidal effects disrupt and distort the old patterns leading to new structures, and finally to a new stable configuration.

    The pull of the Moon that produces the twice-daily rise and fall of the Earth’s oceans illustrates the nature of tidal interactions. Tides between galaxies are much more disruptive than oceanic tides for two main reasons. Firstly, stars in galaxies, unlike the matter that makes up the Earth, are bound together only by the force of gravity. Secondly, galaxies can pass much closer to each other, relative to their size, than do the Earth and the Moon. The billions of stars in each interacting galaxy move individually, following the pull of gravity from all the other stars, so the interwoven tidal forces can produce the most intricate and varied effects as galaxies pass close to each other.

    Typically the first tentative sign of an interaction will be a bridge of matter as the first gentle tugs of gravity tease out dust and gas from the approaching galaxies (IC 2810).

    Magellanic Bridge ESA_Gaia satellite. Image credit V. Belokurov D. Erkal A. Mellinger.

    As the outer reaches of the galaxies begin to intermingle, long streamers of gas and dust, known as tidal tails, stretch out and sweep back to wrap around the cores (NGC 6786, UCG 335, NGC 6050). These long, often spectacular, tidal tails are the signature of an interaction and can persist long after the main action is over. As the galaxy cores approach each other their gas and dust clouds are buffeted and accelerated dramatically by the conflicting pull of matter from all directions (NGC 6621, NGC 5256). These forces can result in shockwaves rippling through the interstellar clouds (ARP 148). Gas and dust are siphoned into the active central regions, fuelling bursts of star formation that appear as characteristic blue knots of young stars (NGC 454). As the clouds of dust build they are heated so that they radiate strongly, becoming some of the brightest (luminous and ultraluminous) infrared objects (APG 220) in the sky.

    3
    Fifty nine new images of colliding galaxies make up the largest collection of Hubble images ever released together. As this astonishing Hubble atlas of interacting galaxies illustrates, galaxy collisions produce a remarkable variety of intricate structures.
    Most of the 59 new Hubble images are part of a large investigation of luminous and ultraluminous infrared galaxies called the GOALS project (Great Observatories All-sky LIRG Survey). This survey combines observations from Hubble, the NASA Spitzer Space Observatory, the NASA Chandra X-Ray Observatory and NASA Galaxy Explorer.

    NASA/Galex telescope

    NASA/Spitzer Infrared Telescope

    NASA/Chandra Telescope

    The Hubble observations are led by Professor Aaron S. Evans from the University of Virginia and the National Radio Astronomy Observatory (USA). Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech)

    These objects emit up to several thousand billion times the luminosity of our Sun. They are the most rapidly star-forming galaxies in today’s Universe and are linked to the occurrence of quasars. Unlike standard spiral galaxies like the Milky Way, which radiate from stars and hot gas distributed over their entire span of perhaps 100,000 light-years, the energy in luminous and ultraluminous infrared galaxies is primarily generated within their central portion, over an extent of 1000 to 10,000 light-years. This energy emanates both from vigorous star formation processes, which can generate up to a few hundred solar masses of new stars per year (in comparison, the Milky Way generates a few solar masses of new stars per year), and from massive accreting black holes, a million to a billion times the mass of the Sun, in the central region.

    Intense star formation regions and high levels of infrared and far-infrared radiation are typical of the most active central period of the interaction and are seen in many of the objects in this release. Other visible signs of an interaction are disruptions to the galaxy nuclei (NGC 3256, NGC 17). This disruption may persist long after the interaction is over, both for the case where a larger galaxy has swallowed a much smaller companion and where two more closely matched galaxies have finally separated.

    Most of the 59 new Hubble images are part of a large investigation of luminous and ultraluminous infrared galaxies called the GOALS project (Great Observatories All-sky LIRG Survey). This survey combines observations from Hubble, the NASA Spitzer Space Observatory, the NASA Chandra X-Ray Observatory and NASA Galaxy Explorer. The Hubble observations are led by Professor Aaron S. Evans from the University of Virginia and the National Radio Astronomy Observatory (USA).

    A number of the interacting galaxies seen here are included in the The Atlas of Peculiar Galaxies, a remarkable catalogue produced by the astronomer Halton Arp in the mid-1960s that built on work by B.A. Vorontsov-Velyaminov from 1959. Arp compiled the catalogue in a pioneering attempt to solve the mystery of the bizarre shapes of galaxies observed by ground-based telescopes. Today, the peculiar structures seen by Arp and others are well understood as the result of complex gravitational interactions.

    Acknowledgements for this photo release:

    Project lead: Lars Lindberg Christensen
    Image processing: Davide de Martin (ESA/Hubble) and Zolt Levay (STScI)
    Cosmetic cleaning: Amit Kapadia, Nuno Marques, Maximilian Kaufl (ESA/Hubble)
    Colour correction and cosmetic adjustments: Zolt Levay (STScI) & Martin Kornmesser (ESA/Hubble)
    HST Principle Investigator: A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook), and the PIs of Hubble Proposals 9735, 11091, 6276, 10575, 7129, 7467, 6438.
    Astronomical processing pipeline: The STScI ACS team
    Data Archiving and pipeline implementation: The ESO/ST-ECF Archive and the STScI Archive
    Textual information: Ana Margarida Lopes, Will Gater, Anne Rhodes, Raquel Yumi Shida & Lars Lindberg Christensen (ESA/Hubble)
    Web products: Raquel Yumi Shida (ESA/Hubble) & Stratis Kakadelis (STScI)

    From Manu:

    4
    NGC 5256
    A riot of color and light dances through this peculiarly shaped galaxy, NGC 5256 . Smoke plumes are released in all directions and the bright nucleus illuminates the chaotic regions of gas and dust swirling in the center of the galaxy. Its strange structure is due to the fact that this is not a galaxy, but two, in the process of a galactic collision.
    NGC 5256 , also known as Markarian 266, is about 350 million light years from Earth in the constellation Ursa Major (The Great Bear) [1]. It is composed of two disk galaxies whose nuclei are currently 13 000 light years away. Its gas, dust and constituents stars swirled together in a cosmic vigorous mixing, in bright lighting newborn star formation regions through star Galaxy.

    Notes
    [1] NGC 5256 has been previously photographed by Hubble as part of a collection of 59 images of galaxies fused launched the 18th anniversary of Hubble 24 April 2008. This adds new image data H-alpha taken from the camera field ample 3 (WFC3) data previously available, which causes the gas to be visible.

    See the full Hubble article here .
    See Manu’s article here .
    Please help promote STEM in your local schools.

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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 12:22 pm on December 10, 2017 Permalink | Reply
    Tags: , , , , , Manu Garcia‎, The Chamaeleon I region   

    From ESA via Manu: “Star formation in the Chamaeleon” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    ESA Space For Europe Banner

    European Space Agency

    1

    27/11/2017

    ESA/Herschel spacecraft

    A dark cloud when observed with optical telescopes, the Chamaeleon I region reveals itself as an active hub of star formation in this far-infrared image from ESA’s Herschel space observatory. Only around 550 light-years away in the southern constellation of Chamaeleon, it is one of the closest areas where stars are bursting into life.

    Launched in 2009, Herschel observed the sky at far-infrared and submillimetre wavelengths until 2013. Sensitive to the heat from the small fraction of cold dust mixed in with the clouds of gas where stars form, it provided unprecedented views of the interstellar material that pervades our Milky Way galaxy.

    Herschel’s extraordinary scans uncovered a vast and intricate network of filamentary structures everywhere in the Galaxy, confirming that filaments are crucial elements in the process of star formation.

    After a filamentary web arises from turbulent motions of gas in the interstellar material, gravity takes over, but only in the densest filaments, which become unstable and fragment into compact objects – the seeds of future stars.

    Chamaeleon I is no exception, with several elongated structures weaving their way through the cloud. Most of the star-forming activity is taking place at the convergence of filaments – in the bright area towards the top right and in the vaster region just left of the image centre, sprinkled with newborn stars that are heating up the material in their surroundings.

    Analysing images like this, astronomers have identified more than 200 young stars in this two million year-old cloud. Most of these stars are still surrounded by a disc of leftover material from the formation process, which may evolve and later give rise to planets.

    Owing to its relative vicinity, Chamaeleon I is an ideal laboratory to explore protoplanetary discs and their properties using Herschel data.

    This image was first published in a paper by Á. Ribas et al. (2013) [Astronomy & Astrophysics], which presents a study of protoplanetary discs in this region. It was also shared as a #HerschelMoment during a public campaign on Twitter to celebrate the legacy of ESA’s observatory in September 2017.

    This three-colour image combines Herschel observations at 70 microns (blue), 160 microns (green) and 250 microns (red), and spans about 2.5º on the long side; north is to the right and east is up.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 11:44 am on December 7, 2017 Permalink | Reply
    Tags: , , , Blazar CTA 102, , Emission from the centre of a galaxy has a serpentine shape, , Manu Garcia‎   

    From Manu at IAC: “Emission from the centre of a galaxy has a serpentine shape” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    IAC

    Instituto de Astrofísica de Canarias – IAC

    Dec. 4, 2017
    Contact in IAC:
    José Antonio Acosta Pulido jap@iac.es

    An international group of scientists led by members of the National Instituto of Astrophysics (Osservatorio Astronomico di Torino (INAF-OATo) with participation by researchers from the Instituto de Astrofísica de Canarias (IAC) has discovered a peculiar spiral jet with many twists. The results of these observations are published today in Nature.

    1
    No image caption or credit.

    3
    No image caption or credit.

    4
    No image caption or credit.

    A blazar is an astronomical object within an elliptical galaxy, at whose centre there is a supermassive black hole which emits jets of radiation and particles with huge energies. When these are directed towards the Earth we can detect them. They are among the most energetic phenomena in the universo.

    In the second half of last year the blazar CTA 102, which is 7,600 million light years from Earth, brightened considerably, drawing the attention of all the astronomers who specialise in this kind of objects. The peak emission was detected on December 28th when it was 3,500 times greater than the brightness minima observed in previous years. This event was so exceptional that for a few days this object was the brightest blazar observed until now.

    To follow this event the researchers of the Astrophysical Observatory of Turin (OATo) coordinated an intense multifrecuency observational campaign in the framework of of the international collaboration Whole Earth Blazar Telescope (WEBT). More than 40 telescopes in the northern hemisphere took thousands of observations in the visible, radio, and near infrared ranges, which enabled the production of detailed light curves. Among the telescopoes used in the collaboration were the Carlos Sánchez Telescope and the IAC-80 and STELLA telescopes, all of them at the Teide Observatory (Izaña, Tenerife).

    3
    IAC Observatorio del Teide, on Mount Teide at 2,390 metres (7,840 ft), located on Tenerife, Spain. It is operated by the Instituto de Astrofísica de Canarias

    “This large quantity of data has enabled us to verify the hypothesis that the variability of this object is due to changes in the relativistic Doppler factor” explains José Antonio Acosta Pulido, a researcher at the IAC and one of the authors of the article, which is published today in Nature magazine.

    The researchers’ interpretation is that the jet is “serpentine and inhomogeneous” because it emits radiation over a range of frequencies and from different zones, which change their orientation due to the instabilities in the jet, or to orbital motions.

    Within this interpretation Acosta explains that “The incredible rise inthe luminosity was due to the increased alignment (this occurred nearly 8 thousand million years ago) of the emitting zone of the jet with our line of sight to the object” Thanks to these observatinos the model used in this research is supported both theoretically and observationally.

    “Three dimensional numerical simulations, taking into account the magnetohydrodynamic properties and the relativistic velocities, predict the appearance and the propagation of instabilities in the jet, which then distort it “ explains Acosta. He adds that “ In addition the images obtained by radio-interferometry show,on scales of one parsec (some three light years) that the jet appears to be helical, and contains many vórtices. The picture which emerges is one of a twisting jet whose emission is amplified at different wavelengths at different times, by the “lighthouse effect”. The orientation in December 2016 was especially favourable for the extraordinary amplification observed.

    The Observatories of the Instituto de Astrofísica de Canarias (IAC) are part of the network of Singular Scientific and Technical Infrastructures (ICTS) of Spain.

    Other researchers:

    Carlos Lázaro
    Francesca Pinna
    Cristina Protasio
    F.J. Redondo-Lorenzo
    Gustavo Rodríguez Coira
    Noel Castro Segura
    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

    The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
    The Centro de Astrofísica en La Palma (CALP)
    The Observatorio del Teide (OT), in Izaña (Tenerife).
    The Observatorio del Roque de los Muchachos (ORM), in Garafía (La Palma).

    These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

    The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

    The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

    The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

    The IAC’s research programme includes astrophysical research and technological development projects.

    The IAC is also involved in researcher training, university teaching and outreachactivities.

    The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.


    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, SpainGran Telescopio CANARIAS, GTC

     
  • richardmitnick 1:35 pm on November 26, 2017 Permalink | Reply
    Tags: , , , , , Herschel's Chronicles of Galaxy Evolution, Manu Garcia‎   

    From Herschel at ESA via Manu: “Herschel’s Chronicles of Galaxy Evolution” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    ESA Space For Europe Banner

    European Space Agency

    September 20, 2017 [Thanks to Manu for digging out this gem of an article.]

    Göran Pilbratt
    Herschel Project Scientist
    Directorate of Science
    European Space Agency
    Email: gpilbratt@cosmos.esa.int
    Phone: +31-71-565-3621

    Philip Appleton
    Herschel Project Scientist and Task Lead at Caltech/IPAC-Herschel
    NASA Herschel Science Center
    Email: apple@ipac.caltech.edu
    Phone: +1-626-395-3119

    1

    Delving deep into the history of our cosmos, the Herschel Space Observatory scrutinised hundreds of thousands of star-forming galaxies, peering back in time to when the Universe was less than one billion years old.

    ESA/Herschel spacecraft

    These observations probed the peak epoch of stellar production, about ten billion years ago, when galaxies were forming stars roughly ten times faster than their present counterparts.

    Looking at the starry spectacle of the night sky, we might be tricked by its seemingly timeless beauty to think that the multitude of distant suns have been there since the beginning of time. But, if our eyes could peer back into cosmic history up to the first few seconds of our Universe, almost 14 billion years ago, they would be treated to a very different view.

    Shortly after the Big Bang – the hot and dense phase that sets our cosmic tale into motion – the Universe was very different from what we can observe nowadays, and it took a few hundred million years for stars and galaxies to start to emerge from the primordial ‘soup’ that filled the early cosmos.

    Piecing together how galaxies formed and evolved, giving birth to stars at different paces throughout the history of the Universe, is one of the most intriguing and challenging topics in present day astrophysics and cosmology research.

    Infrared is the key

    In their quest to investigate how galaxies differ at various cosmic epochs, astronomers have been collecting increasingly larger samples, searching for the light that was emitted by galaxies many billions of years ago and that has been travelling across the Universe ever since. These studies greatly benefit from combining observations at different wavelengths of light, with the infrared band being crucial to pinpoint galaxies that are fiercely forming stars.

    Star formation in galaxies takes place within dense clouds of gas that, for most of cosmic history, also contain small amounts of dust. Newborn stars shine brightly in ultraviolet and visible wavelengths, but only about half of this starlight, on average, leaves a galaxy unhindered; neighbouring dust grains absorb the other half, radiating it again but, this time, at longer wavelengths.

    As a result of the dust interspersed in the interstellar material, galaxies emit roughly 50 per cent of their total light at mid-infrared, far-infrared, and sub-millimetre wavelengths –between 8 micron and 1 mm – with a peak in the far-infrared, around 50-200 microns. For this reason, observations in this spectral range are fundamental for quantifying a galaxy’s star formation activity.

    In addition, the expansion of the Universe stretches the wavelengths of light emitted by distant objects. This effect, known as redshift, becomes increasingly more significant the farther a galaxy is from us.

    This causes the peak of dust emission to move from the far-infrared to sub-millimetre wavelengths. Therefore observations that cover these two portions of the electromagnetic spectrum complement each other, capturing dusty emission from star formation in both nearby and distant galaxies.

    Performing observations at infrared wavelengths with telescopes on the ground, however, is generally difficult – if not impossible – because of the presence of Earth’s atmosphere, so astronomers turned to space.

    In the early 1980s, the US-Dutch-British Infrared Astronomical Satellite (IRAS) was the first space mission to map the sky in the far-infrared, followed by ESA’s Infrared Space Observatory (ISO) in the late 1990s, NASA’s Spitzer Space Telescope, launched in 2003, and JAXA’s Akari, which operated between 2006 and 2011.

    NASA IRAS spacecraft

    2
    ISO spacecraft, ESA

    NASA/Spitzer Infrared Telescope

    JAXA AKARI spacecraft

    With mid-infrared observations from ISO and Spitzer, astronomers started to perceive the glow of warm dust from individual star-forming galaxies sprinkled across the Universe’s history. But it was only with ESA’s Herschel Space Observatory, launched in 2009 and operational until 2013, that these investigations unleashed their full potential.

    The observatory’s broad spectral coverage, including the far-infrared and sub-millimetre range, extended to longer wavelengths than those probed by Spitzer, ISO, and Akari. As a result, astronomers could sense cooler dust than that which had been detected by its predecessors.

    With its unprecedented angular resolution, Herschel could also spot galaxies that had been missed by these earlier observatories at the wavelengths they had in common.

    In addition, and perhaps most importantly, its particular spectral range made it possible to catch galaxies whose light had been redshifted to longer wavelengths than those probed by its predecessors, tracing out star formation to greater distances and thus earlier times in cosmic history.

    With a 3.5-metre primary mirror, Herschel sported the largest infrared telescope flown to date, granting astronomers unprecedented sensitivity that was crucial to observe star-forming galaxies across the Universe.

    Scrutinising the evolution of galaxies was the focus of various Key Programmes that dedicated over 2000 hours to these observations – among them, the Herschel Multi-tiered Extragalactic Survey, the PACS Evolutionary Probe, and the Herschel Thousand Degree Survey.

    Following in the footsteps of previous studies based on Spitzer data, Herschel allowed astronomers to resolve the diffuse ‘fog’ known as the cosmic infrared background radiation into hundreds of thousands of individual, actively star-forming galaxies, seen as they were at a variety of past epochs. Herschel’s contribution was crucial to push the observations up to the time when the Universe was less than one billion years old, probing the full period when star formation peaked and even beyond.

    This result, which has opened new avenues to study the evolution of galaxies, is somewhat suggestive of the revolutionary observations by Galileo who, just over four centuries before, had pointed the newly invented telescope at the diffuse white glow of the Milky Way, breaking it down into a myriad of individual stars.

    The heyday of star formation

    With its deep surveys of several regions of the sky, Herschel revealed a Universe teeming with star-forming galaxies, their presence uncovered by the glow of dust heated by the stars in the making.

    Measuring how bright a galaxy shines in the far-infrared can inform astronomers about how much dust is there and how cool it is, which can be used, in turn, to determine the pace of the galaxy’s star formation activity.

    In the present Universe, galaxies produce stars at a rather leisurely pace, with our Milky Way giving birth to only a few Sun-like stars every year. However, galaxies have been far more prolific in the past, and Herschel has been instrumental in estimating just how much so.

    Stars and galaxies have been bursting into life since the Universe was about half a billion years old, and astronomers now agree that this activity peaked a few billion years later. At that glorious epoch, Herschel confirmed that galaxies were forming stars roughly ten times faster, on average, than they are nowadays.

    Shortly after, the average rate of star formation in galaxies began to decline, and it has been consistently doing so over the past ten billion years of cosmic history.

    With such a marked difference in the star-forming activity of present and past galaxies, it is legitimate to wonder whether the physical processes that regulate the stellar production also underwent any substantial change over the eons.

    Most galaxies in today’s Universe are making stars in a steady, gentle fashion, and only rarely do dynamical interactions of galaxies, or mergers, trigger the occasional, intense burst of stellar birth.

    Astronomers suspected that galactic mergers might have been responsible for the higher pace of star formation at its peak, ten billion years ago, but hints from Spitzer and, later, more robust evidence from Herschel surprisingly revealed that this was not the case.

    In spite of their higher production rates, most galaxies at earlier cosmic epochs seem to be quite ‘ordinary’: their greater productivity is likely an effect of cold gas – the raw material to make stars – being more plentiful at those times.

    Within this scenario, earlier galaxies are not concealing any mysterious mechanism that boosts their star-making efficiency, but are most likely just scaled-up versions of the galaxies we observe at the present time.

    This result relegates merger-triggered starbursts to a minor role in the total history of star formation; the decisive ingredient seems to be a steady supply of cold gas, which could well be provided by intergalactic streams – as suggested by numerical simulation of cosmic structure formation.

    In addition, Herschel demonstrated that, at any given time in the Universe, the vast majority of star-forming galaxies seem to obey a very simple rule: the greater the mass of stars hosted in a galaxy, the faster this galaxy is forming new stars. This relation, called the Galaxy Main Sequence, had already been identified using Spitzer observations of galaxies in more recent epochs, but Herschel confirmed that it applies also to earlier times.

    That such a relation seems to be true across most of cosmic history is remarkable, suggesting that relatively simple mechanisms must be regulating the complex process of a galaxy turning its interstellar material into stars.

    Only a small fraction of extremely prolific starburst galaxies appear to break this rule, in the earlier and later Universe alike. Herschel did find that such behemoths were slightly more abundant at earlier times, but demonstrated that they were never the primary channel of star formation at any epoch. Indeed, the fierce activity of stellar production observed in starburst galaxies seems not to be sustainable over long periods of time, causing them to rapidly quench their star formation.

    More recently, new analyses of Herschel observations have shown that the situation may not be so clear-cut after all. These studies indicate that the Galaxy Main Sequence might break down also in the case of very massive galaxies, suggesting that, as galaxies grow more massive by accreting cold gas, they could reach a point where they stop forming stars very efficiently. The reasons for this change in behaviour are still being investigated.

    The role of feedback

    What caused the drop in star formation rate, ten billion years ago, and its overall declining trend ever since?

    While it is evident that, in the past, galaxies had at their disposal a much larger supply of raw material from which to form stars than they do at present, the physical processes that drained them of their reservoirs of interstellar gas (and dust) are still not fully understood. Similarly, astronomers are still probing the possible mechanisms underlying the Galaxy Main Sequence.

    Another open issue concerns a striking similarity observed between the long-term history of two apparently disparate processes that take place in galaxies: the formation of stars and the accretion of matter onto the supermassive black holes that are lurking at their cores: both processes appear to peak around ten billion years ago. How can the evolution of black holes, which are relatively small-sized and confined at the centre of their host galaxies, be linked to the star-forming activity that takes place on much larger scales?

    The answer to some – or perhaps all – of these questions might lie in the ‘feedback’ effects exerted on the interstellar material that pervades a galaxy by stellar radiation and winds, supernova explosions, and outflows possibly triggered by the activity of its central black hole.

    Astronomers have long been studying the role of feedback on galaxy evolution using a variety of observations across the spectrum. Looking at nearby galaxies that are forming stars more briskly than most of their neighbours, Herschel brought important input to this quest.

    Using Herschel data, astronomers discovered massive outflows of molecular gas streaming away from the cores of several star-forming galaxies in the local Universe. While outflowing gas in neutral and ionised form had been observed in earlier studies, this was the first detection of massive outflows of molecular gas – crucial in the making of stars – being pushed away from a galaxy. The strongest outflows were seen in galaxies that host actively accreting supermassive black holes at their centre, hinting at a role for black-hole feedback in draining a galaxy’s reservoir of star-forming material.

    Further clues were found in nearby radio galaxies, which exhibit symmetric jets of plasma flying out, at the speed of light, from the central black hole. These jets definitely have the power to affect the gas on much larger scales and perhaps even to impede the host galaxy’s star formation.

    Herschel observations were also key to proving a crucial aspect in these feedback matters, uncovering for the first time the causal link between the black hole activity at the centre of a galaxy and the gas outflows seen on much larger scales. This was made possible by comparing a galactic-wide outflow of molecular gas, detected by Herschel, with X-ray data probing a powerful wind of ionised gas driven by the black hole at the core of the galaxy. Observing these two phenomena in the same galaxy for the first time, astronomers further demonstrated the role played by black holes in regulating the formation of stars in their host galaxies.

    Making sense of it all

    To get to the bottom of how differently galaxies evolved across the history of the Universe, observations are compared with the predictions from computer simulations, which attempt to reproduce the build-up of cosmic structures on very large scales. Many new simulations have also embraced the very challenging task of including a number of small-scale processes to account for the feedback effects caused by star formation or the activity of supermassive black holes.

    As for Herschel’s survey of over 12 billion years of star formation, a comparison with the simulated cosmos showed that some processes underlying galaxy evolution seem to be well understood, but many details remain unclear. Simulations are still far from reproducing the complex and diverse properties recorded by surveys of galaxies, especially concerning the link between feedback and star formation, and there is still much work to do before all pieces of this cosmic puzzle fall into place.

    Nevertheless, Herschel’s unprecedented observations are greatly helping astronomers in their ambitious endeavour of assembling the complex history of how stars and galaxies formed and evolved in the cosmos. Pushing the experimental boundaries farther than any of its predecessors, the mission has revealed a number of previously hidden gems, near and far, that have been crucial to piecing together this intriguing tale, while at the same time it also uncovered new mysteries that will keep astronomers busy for the foreseeable future.

    Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA’s Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel’s three science instruments. The NASA Herschel Science Center, part of IPAC at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.

    See the full article here .

    Please help promote STEM in your local schools.

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 1:53 pm on November 25, 2017 Permalink | Reply
    Tags: , , , , , Manu Garcia‎, ,   

    From Spitzer via Manu: “Spitzer Reveals Ancient Galaxies’ Frenzied Starmaking” 


    Manu Garcia, a friend from IAC.

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    NASA/Spitzer Telescope


    Spitzer

    10.30.17

    1

    A deep look back to the early universe by NASA’s Spitzer Space Telescope has revealed a surprisingly rowdy bunch of galaxies. Within a large galaxy sample observed 1.5 billion years after the Big Bang, Spitzer witnessed around 15 percent of galaxies undergoing bouts of extreme starmaking, called starbursts. The discovery suggests that starbursts—a rare phenomenon in the modern cosmos—were actually relatively common in the past, and played a major role in creating our universe’s stars.

    Typically, galaxies go with a take-it-slow approach to starmaking. Over billions of years, that unhurried stellar production has been credited with forging almost all stars in existence. The new findings, however, show starburst galaxies cranking out upwards of half of the total new stars in the cosmic era under study. Moving forward, astronomers will have to ensure galactic evolution theories can account for these more frequent frenzies of starmaking.

    “This research shows for the first time that starburst galaxies are much more important than previously thought in the early star formation history of the universe,” said Karina Caputi, an associate professor at the University of Groningen in the Netherlands. Caputi is lead author of a new paper describing the results, published on Oct 30 in The Astrophysical Journal.

    “We have discovered an unknown population of starburst galaxies that could change the way we think many galaxies grow their stars,” said Karina.

    Caputi and her colleagues pored over a voluminous dataset of nearly 6000 distant galaxies observed as part of Spitzer’s Matching Survey of the UltraVISTA ultra-deep Stripes (SMUVS) program. The scientists looked for a type of light, called H-alpha, emitted by the element hydrogen. This glow marks regions where new groups of stars have just formed from the gravitational collapse of giant clouds of gas and dust. Over vast cosmic distances—like the 12 billion light years to the galaxies in Caputi’s study—the expansion of the universe stretches H-alpha’s visible, pink-reddish light into the infrared wavelengths seen by Spitzer. Researchers can therefore leverage Spitzer as a valuable tool in gauging the levels of star formation in the early universe.

    Prior investigations have focused mostly on starbursts breaking out in galaxies with high masses, usually selected out of small datasets. The catalog of observations Caputi’s team went through offered a more complete picture, though, by capturing numerous intermediate-mass galaxies also flush with the signs of starburst activity. Bringing those overlooked galaxies into the fold boosted the overall starburst percentage from negligible to a significant 15 percent, and with it, over half of the total starmaking at that time in the universe’s chronology. “We analyzed a much larger and more representative galaxy sample,” Caputi says.

    The development of a new star—from cold, diffuse gas cloud to a hot, concentrated ball of matter—is a process that spans tens of millions of years. At any given time in a galaxy, only so many stars-to-be are going through this process; our own Milky Way languidly produces only about one Sun’s-mass-worth of new stars annually. Yet in a starburst galaxy, that rate of stellar creation can be hundreds of times faster.

    As a result, although their quantities differ, slow-poke and fast-pace galaxies ultimately make similar contributions to the overall stellar budget. “There appear to be two types of galaxies which form stars: some are more numerous, but grow more slowly. The others are less numerous, but grow much faster,” Caputi explained. “In the end, both groups can form the same total amount of stars.”

    What exactly is causing all the starbursts remains a mystery. Galaxy mergers, where the diffuse star-forming materials in two galaxies mix into gas clouds dense enough to ignite star formation, stand as highly likely candidates. Gravitational interactions with neighboring galaxies, or encounters with uncommonly thick patches of matter in the barren expanses between galaxies, might also fire up starbursts.

    “We still have a lot of work to do in understanding why galaxies go into a starburst mode,” says Caputi. “Now that we have a sense of just how significant these furious periods of activity are for giving us such a large amount of the universe’s stars, we are highly motivated to get to the bottom of the mystery.”

    This research has been funded by the European Research Council through the Consolidator Grant ID 681627-BUILDUP.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory located on the campus of the California Institute of Technology and part of NASA’s Infrared Processing and Analysis Center.

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