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  • richardmitnick 2:29 pm on March 31, 2020 Permalink | Reply
    Tags: "Hubble Finds Best Evidence for Elusive Mid-Sized Black Hole", (IMBH)-intermediate-mass black hole, , , , , ESA/XMM-Newton, , , The X-ray source named 3XMM J215022.4−055108   

    From NASA/ESA Hubble Telescope: “Hubble Finds Best Evidence for Elusive Mid-Sized Black Hole” 

    NASA/ESA Hubble Telescope

    From NASA/ESA Hubble Telescope

    March 31, 2020

    Leah Ramsay
    Space Telescope Science Institute, Baltimore, Maryland
    667-218-6439
    lramsay@stsci.edu

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

    Dacheng Lin
    University of New Hampshire, Durham, New Hampshire
    dacheng.lin@unh.edu

    High-resolution imaging reveals black hole’s hideout in extra-galactic star cluster.

    1
    About This Image. Illustration of Mid-Sized Black Hole Eating a Star
    This artist’s concept depicts a cosmic homicide in action. A wayward star is being shredded by the intense gravitational pull of a black hole that contains tens of thousands of solar masses. The stellar remains are forming an accretion disk around the black hole. Flares of X-ray light from the super-heated gas disk alerted astronomers to the black hole’s location; otherwise it lurked unknown in the dark. The elusive object is classified as an intermediate-mass black hole (IMBH), as it is much less massive than the monster black holes that dwell in the centers of galaxies. Therefore, IMBHs are mostly quiescent because they do not pull in as much material, and are hard to find. Hubble observations provide evidence that the IMBH dwells inside a dense star cluster. The cluster itself may be the stripped-down core of a dwarf galaxy. Credits: NASA/ESA and D. Player (STScI)

    Astronomers have found the best evidence for the perpetrator of a cosmic homicide: a black hole of an elusive class known as “intermediate-mass,” which betrayed its existence by tearing apart a wayward star that passed too close.

    Weighing in at about 50,000 times the mass of our Sun, the black hole is smaller than the supermassive black holes (at millions or billions of solar masses) that lie at the cores of large galaxies, but larger than stellar-mass black holes formed by the collapse of a massive star.

    These so-called intermediate-mass black holes (IMBHs) are a long-sought “missing link” in black hole evolution. Though there have been a few other IMBH candidates, researchers consider these new observations the strongest evidence yet for mid-sized black holes in the universe.

    It took the combined power of two X-ray observatories and the keen vision of NASA’s Hubble Space Telescope to nail down the cosmic beast.

    “Intermediate-mass black holes are very elusive objects, and so it is critical to carefully consider and rule out alternative explanations for each candidate. That is what Hubble has allowed us to do for our candidate,” said Dacheng Lin of the University of New Hampshire, principal investigator of the study. The results are published on March 31, 2020 in The Astrophysical Journal Letters.

    The story of the discovery reads like a Sherlock Holmes story, involving the meticulous step-by-step case-building necessary to catch the culprit.

    Lin and his team used Hubble to follow up on leads from NASA’s Chandra X-ray Observatory and the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton).

    NASA/Chandra X-ray Telescope

    ESA/XMM Newton

    In 2006 these high-energy satellites detected a powerful flare of X-rays, but were not sure if they originated from inside or outside of our galaxy. Researchers attributed it to a star being torn apart after coming too close to a gravitationally powerful compact object, like a black hole.

    Surprisingly, the X-ray source, named 3XMM J215022.4−055108, was not located in a galaxy’s center, where massive black holes normally would reside. This raised hopes that an IMBH was the culprit, but first another possible source of the X-ray flare had to be ruled out: a neutron star in our own Milky Way galaxy, cooling off after being heated to a very high temperature. Neutron stars are the crushed remnants of an exploded star.

    Hubble was pointed at the X-ray source to resolve its precise location. Deep, high-resolution imaging provides strong evidence that the X-rays emanated not from an isolated source in our galaxy, but instead in a distant, dense star cluster on the outskirts of another galaxy — just the type of place astronomers expected to find an IMBH. Previous Hubble research has shown that the mass of a black hole in the center of a galaxy is proportional to that host galaxy’s central bulge. In other words, the more massive the galaxy, the more massive its black hole. Therefore, the star cluster that is home to 3XMM J215022.4−055108 may be the stripped down core of a lower-mass dwarf galaxy that has been gravitationally and tidally disrupted by its close interactions with its current larger galaxy host.

    IMBHs have been particularly difficult to find because they are smaller and less active than supermassive black holes; they do not have readily available sources of fuel, nor as strong a gravitational pull to draw stars and other cosmic material which would produce telltale X-ray glows. Astronomers essentially have to catch an IMBH red-handed in the act of gobbling up a star. Lin and his colleagues combed through the XMM-Newton data archive, searching hundreds of thousands of observations to find one IMBH candidate.

    The X-ray glow from the shredded star allowed astronomers to estimate the black hole’s mass of 50,000 solar masses. The mass of the IMBH was estimated based on both X-ray luminosity and the spectral shape. “This is much more reliable than using X-ray luminosity alone as typically done before for previous IMBH candidates,” said Lin. “The reason why we can use the spectral fits to estimate the IMBH mass for our object is that its spectral evolution showed that it has been in the thermal spectral state, a state commonly seen and well understood in accreting stellar-mass black holes.”

    This object isn’t the first to be considered a likely candidate for an intermediate-mass black hole. In 2009 Hubble teamed up with NASA’s Swift observatory and the XMM-Newton X-ray space telescope to identify what is interpreted as an IMBH, called HLX-1, located towards the edge of the galaxy ESO 243-49.

    NASA Neil Gehrels Swift Observatory

    It too is in the center of a young, massive cluster of blue stars, that may be a stripped down dwarf galaxy core. The X-rays come from a hot accretion disk around the black hole. “The main difference is that our object is tearing a star apart, providing strong evidence that it is a massive black hole, instead of a stellar-mass black hole as people often worry about for previous candidates including HLX-1,” Lin said.

    Finding this IMBH opens the door to the possibility of many more lurking undetected in the dark, waiting to be given away by a star passing too close. Lin plans to continue his meticulous detective work, using the methods his team has proved successful. Many questions remain to be answered. Does a supermassive black hole grow from an IMBH? How do IMBHs themselves form? Are dense star clusters their favored home?

    See the full article here .


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    Please help promote STEM in your local schools.

    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 12:11 pm on May 7, 2019 Permalink | Reply
    Tags: "Storm in the Teacup quasar", , , , , , ESA/XMM-Newton, ,   

    From European Space Agency: “Storm in the Teacup quasar” 

    ESA Space For Europe Banner

    From European Space Agency

    06/05/2019

    1
    This image shows a quasar nicknamed the Teacup due to its shape. A quasar is an active galaxy that is powered by material falling into its central supermassive black hole. They are extremely luminous objects located at great distances from Earth. The Teacup is 1.1 billion light years away and was thought to be a dying quasar until recent X-ray observations shed new light on it.

    X-ray: NASA/CXC/University of Cambridge/G. Lansbury et al; optical: NASA/STScI/W. Keel et al

    ESA/XMM Newton

    NASA/Chandra X-ray Telescope

    NASA/ESA Hubble Telescope

    The Teacup was discovered in 2007 as part of the Galaxy Zoo project, a citizen science project that classified galaxies using data from the Sloan Digital Sky Survey. A powerful eruption of energy and particles from the central black hole created a bubble of material that became the Teacup’s handle, which lies around 30 000 light years from the centre.

    Observations revealed ionised atoms in the handle of the Teacup, possibly caused by strong radiation coming from the quasar in the past. This past level of radiation dwarfed the current measurements of the luminosity from the quasar. The radiation seemed to have diminished by 50 to 600 times over the last 40 000 to 100 000 years, leading to the theory that the quasar was rapidly fading.

    But new data from ESA’s XMM-Newton telescope and NASA’s Chandra X-ray observatory reveal that X-rays are coming from a heavily obscured central source, which suggests that the quasar is still burning bright beneath its shroud. While the quasar has certainly dimmed over time, it is nowhere near as significant as originally thought, perhaps only fading by a factor of 25 or less over the past 100 000 years.

    The Chandra data also showed evidence for hotter gas within the central bubble, and close to the ‘cup’ which surrounds the central black hole. This suggests that a wind of material is blowing away from the black hole, creating the teacup shape.

    In the image shown here the X-ray data is coloured in blue and optical observations from the NASA/ESA Hubble Space Telescope are shown in red and green. Another image including radio data also shows a second ‘handle’ on the other side of the ‘cup’.

    The research is described in The Astrophysical Journal Letters.

    Explore the XMM-Newton data from this study in ESA’s archives.

    See the full article here .


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

    Stem Education Coalition

    The 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 1:37 pm on January 11, 2019 Permalink | Reply
    Tags: , , , , , ESA/XMM-Newton, Host galaxy CGCG 137-068, , , , Team of telescopes finds X-ray engine inside mysterious supernova   

    From European Space Agency: “Team of telescopes finds X-ray engine inside mysterious supernova” 

    ESA Space For Europe Banner

    From European Space Agency

    10 January 2019

    Raffaella Margutti
    Department of Physics and Astronomy
    Northwestern University
    Evanston, IL, USA
    Email: raffaella.margutti@northwestern.edu

    Indrek Vurm
    Tartu Observatory
    University of Tartu, Estonia
    Email: indrek.vurm@ut.ee

    Volodymyr Savchenko
    Department of Astronomy
    University of Geneva, Switzerland
    Email: Volodymyr.Savchenko@unige.ch

    Carlo Ferrigno
    Department of Astronomy
    University of Geneva, Switzerland
    Email: Carlo.Ferrigno@unige.ch

    Giulia Migliori
    INAF–Institute of Radioastronomy
    University of Bologna, Italy
    Email: g.migliori@ira.inaf.it

    Erik Kuulkers
    ESA Integral Project Scientist
    European Space Agency
    Email: ekuulker@sciops.esa.int

    Norbert Schartel
    ESA XMM-Newton Project Scientist
    European Space Agency
    Email: norbert.schartel@sciops.esa.int

    Markus Bauer








    ESA Science Communication Officer









    Tel: +31 71 565 6799









    Mob: +31 61 594 3 954









    Email: markus.bauer@esa.int

    1
    An image of supernova explosion AT2018cow and its host galaxy, CGCG 137-068, which is located some 200 million light years away. The image was obtained on 17 August 2018 using the DEep Imaging and Multi-Object Spectrograph (DEIMOS) on the W. M. Keck Observatory in Hawaii.

    Keck/DEIMOS on Keck 2


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

    Credit: R. Margutti/W. M. Keck Observatory

    The supernova was first spotted on 16 June 2018 with the ATLAS telescope, also in Hawaii. Further observations performed with a large team of telescopes – including ESA’s high-energy space telescopes Integral and XMM-Newton – revealed a source of powerful X-rays at the centre of this unprecedentedly bright and rapidly evolving stellar explosion, suggesting that it could either be a nascent black hole or neutron star with a powerful magnetic field, sucking in the surrounding material. Credit: R. Margutti/W. M. Keck Observatory

    ESA’s high-energy space telescopes Integral and XMM-Newton have helped to find a source of powerful X-rays at the centre of an unprecedentedly bright and rapidly evolving stellar explosion that suddenly appeared in the sky earlier this year.

    ESA/XMM Newton

    ESA/Integral

    The ATLAS telescope in Hawaii first spotted the phenomenon, since then named AT2018cow, on 16 June.

    ATLAS is an asteroid impact early warning system of two telescopes being developed by the University of Hawaii and funded by NASA


    ATLAS telescope, First Asteroid Terrestrial-impact Last Alert system (ATLAS) fully operational 8/15/15 Haleakala , Hawaii, USA, Altitude 4,205 m (13,796 ft)

    They soon realised this was something completely new. In only two days the object exceeded the brightness of any previously observed supernova – a powerful explosion of an aging massive star that expels most of its material into the surrounding space, sweeping up the interstellar dust and gases in its vicinity.

    A new paper, accepted for publication in The Astrophysical Journal, presents the observations from the first 100 days of the object’s existence, covering the entire electromagnetic spectrum of the explosion from radio waves to gamma rays.

    The analysis, which includes observations from ESA’s Integral and XMM-Newton, as well as NASA’s NuSTAR and Swift space telescopes, found a source of high-energy X-rays sitting deep inside the explosion.

    NASA NuSTAR X-ray telescope

    NASA Neil Gehrels Swift Observatory

    The behaviour of this source, or engine, as revealed in the data, suggests that the strange phenomenon could either be a nascent black hole or neutron star with a powerful magnetic field, sucking in the surrounding material.

    “The most exciting interpretation is that we might have seen for the first time the birth of a black hole or a neutron star,” says Raffaella Margutti of Northwestern University, USA, lead author of the paper.

    “We know that black holes and neutron stars form when stars collapse and explode as a supernova, but never before have we seen one right at the time of birth,” adds co-author Indrek Vurm of Tartu Observatory, Estonia, who worked on modelling the observations.

    2
    An image of supernova explosion AT2018cow and its host galaxy, CGCG 137-068, which is located some 200 million light years away. The image was obtained on 17 August 2018 using the DEep Imaging and Multi-Object Spectrograph (DEIMOS) on the W. M. Keck Observatory in Hawaii. The insert in the top left shows a zoom onto the galaxy, indicating the location of the supernova. The supernova was first spotted on 16 June 2018 with the ATLAS telescope, also in Hawaii. Further observations performed with a large team of telescopes – including ESA’s high-energy space telescopes Integral and XMM-Newton – revealed a source of powerful X-rays at the centre of this unprecedentedly bright and rapidly evolving stellar explosion, suggesting that it could either be a nascent black hole or neutron star with a powerful magnetic field, sucking in the surrounding material. Credit: R. Margutti/W. M. Keck Observatory

    The AT2018cow explosion was not only 10 to 100 times brighter than any other supernova previously observed: it also reached peak luminosity much faster than any other previously known event – in only a few days compared to the usual two weeks.

    Integral made its first observations of the phenomenon about five days after it had been reported and kept monitoring it for 17 days. Its data proved crucial for the understanding of the strange object.

    “Integral covers a wavelength range which is not covered by any other satellite,” says Erik Kuulkers, Integral project scientist at ESA. “We have a certain overlap with NuSTAR in the high-energy X-ray part of the spectrum but we can see higher energies, too.”

    So while data from NuSTAR revealed the hard X-ray spectrum in great detail, with Integral the astronomers were able to see the spectrum of the source entirely, including its upper limit at soft gamma-ray energies.

    “We saw a kind of a bump with a sharp cut-off in the spectrum at the high-energy end,” says Volodymyr Savchenko, an astronomer at the University of Geneva, Switzerland, who worked on the Integral data. “This bump is an additional component of the radiation released by this explosion, shining through an opaque, or optically thick, medium.”

    “This high-energy radiation most likely came from an area of very hot and dense plasma surrounding the source,” adds Carlo Ferrigno, also of the University of Geneva.

    3
    The evolution of supernova explosion AT2018cow as observed at soft X-rays with NASA’s Swift (red circles) and ESA’s XMM-Newton (red triangles) space observatories, and at hard X-rays with NASA’s NuSTAR (orange circles) and ESA’s INTEGRAL (yellow circles) satellites. The supernova was first spotted on 16 June 2018 with the ATLAS telescope in Hawaii. The data shown in this animation were collected between 22 June and 22 July. These observations revealed a source of powerful X-rays at the centre of this unprecedentedly bright and rapidly evolving stellar explosion, suggesting that it could either be a nascent black hole or neutron star with a powerful magnetic field, sucking in the surrounding material. Credit: R. Margutti et al (2019)

    Because Integral kept monitoring the AT2018cow explosion over a longer period of time, its data was also able to show that the high-energy X-ray signal was gradually fading.

    Raffaella explains that this high-energy X-ray radiation that went away was the so-called reprocessed radiation – radiation from the source interacting with material ejected by the explosion. As the material travels away from the centre of the explosion, the signal gradually wanes and eventually disappears completely.

    In this signal, however, the astronomers were able to find patterns typical of an object that draws in matter from its surroundings – either a black hole or a neutron star.

    “This is the most unusual thing that we have observed in AT2018cow and it’s definitely something unprecedented in the world of explosive transient astronomical events,” says Raffaella.

    Meanwhile, XMM-Newton looked at this unusual explosion twice over the first 100 days of its existence. It detected the lower-energy part of its X-ray emission, which, according to the astronomers, comes directly from the engine at the core of the explosion. Unlike the high-energy X-rays coming from the surrounding plasma, the lower-energy X-rays from the source are still visible.

    The astronomers plan to use XMM-Newton to perform a follow-up observation in the future, which will allow them to understand the source’s behaviour over a longer period of time in greater detail.

    “We are continuing to analyse the XMM-Newton data to try to understand the nature of the source,” says co-author Giulia Migliori of University of Bologna, Italy, who worked on the X-ray data. “Accreting black holes leave characteristic imprints in X-rays, which we might be able to detect in our data.”

    “This event was completely unexpected and it shows that there is a lot of which we don’t completely understand,” says Norbert Schartel, ESA’s XMM-Newton project scientist. “One satellite, one instrument alone, would never be able to understand such a complex object. The detailed insights we were able to gather into the inner workings of the mysterious AT2018cow explosion were only achievable thanks to the broad cooperation and combination of many telescopes.”

    See the full article here .


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

    Stem Education Coalition

    The 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 12:43 pm on September 28, 2018 Permalink | Reply
    Tags: After falling past the event horizon — the point of no return — nothing can escape a black hole, , , , , ESA/XMM-Newton, Matter clocked speeding toward a black hole at 30 percent the speed of light, PG211+143 is a Seyfert galaxy   

    From Astronomy Magazine: “Matter clocked speeding toward a black hole at 30 percent the speed of light” 

    Astronomy magazine

    From Astronomy Magazine

    September 24, 2018
    Alison Klesman

    The event provides evidence for how early supermassive black holes grew so fast.

    1
    This artist’s concept shows a stream of material flowing toward a black hole as it tears apart and feeds on an unlucky star. NASA/JPL-Caltech

    After falling past the event horizon — the point of no return — nothing can escape a black hole. While the depths of black holes may forever remain a mystery, astronomers can observe the regions around them. In a paper published September 3 in the Monthly Notices of the Royal Astronomical Society, a team of researchers reported, for the first time, spotting a clump of matter falling directly into a distant black hole at nearly one-third the speed of light.

    The observations, which come from the European Space Agency’s orbiting XMM-Newton X-ray observatory, are of the 40 million-solar-mass supermassive black hole at the center of the galaxy PG211+143, about one billion light-years away.

    ESA/XMM Newton

    PG211+143 is a Seyfert galaxy, meaning it hosts a bright, actively feeding black hole at its center pulling in gas and dust from its surroundings. By spreading the X-ray light received from that material out by wavelength, researchers led by Ken Pounds of the University of Leicester clocked a clump of matter falling into the black hole at 30 percent the speed of light — about 56,000 miles per second (90,000 kilometers per second). “We were able to follow an Earth-sized clump of matter for about a day, as it was pulled towards the black hole, accelerating to a third of the velocity of light before being swallowed up by the hole,” said Pounds in a recent press release.

    Peculiarly, the infalling gas showed no rotation — it was not moving in the same way as the larger accretion disk shining around the black hole — from its initial distance at only about 20 times the black hole’s size when it was first spotted.

    Chaos rules

    The traditional “picture” of a black hole has a compact, massive object at the center surrounded by a disk of hot gas. This arises from the fact that, because black holes are so small compared to the mass they hold, infalling matter cannot all simply cram into the black hole at once — instead, it forms a swirling disk, like water flowing down a drain, and eventually approaches the black hole to fall in. As matter moves from the outer disk toward the event horizon, it loses gravitational potential energy, which is converted into radiation that astronomers can observe.

    In this traditional picture, the orbits of material inside the accretion disk are assumed to align with the spin of the black hole itself, forming one single disk. But with that in mind, this observation, in which the infalling matter showed little rotation, is puzzling — at least, until the introduction of recent computer models also developed at the University of Leicester and run using the U.K.’s DiRAC supercomputer facility.

    The theory and models consider the fact that matter can fall toward a black hole from any direction. Perhaps instead of just one disk, multiple, misaligned accretion disks can form as matter streams in. Matter can then “tear” away from these disks, forming rings of material that, if they collide, cancel out their rotation, allowing the material to flow directly into the black hole — just as the astronomers observed.

    2
    This graphic shows what chaotic accretion might look like: At least two misaligned accretion disks, as well as rings of material that have torn off the disks, surround a supermassive black hole. K. Pounds et al. / University of Leicester

    Such a process, dubbed “chaotic accretion,” might be likely in objects such as the supermassive black holes at the centers of galaxies, which can accrete enormous amounts of material, particularly early in their lives or following close interactions with other galaxies. Chaotic accretion could, over time, slow down the spin of a supermassive black hole, which would allow the black hole to more easily gobble matter and grow quickly — and shine brightly — which are characteristics observed in these objects throughout the early universe.

    See the full article here .


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    Please help promote STEM in your local schools.

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  • richardmitnick 6:30 am on August 11, 2018 Permalink | Reply
    Tags: , , , , , ESA/XMM-Newton, Flaring source in NGC 6540   

    From European Space Agency: “Students digging into data archive spot mysterious X-ray source” 

    ESA Space For Europe Banner

    From European Space Agency

    10 August 2018

    Andrea De Luca
    INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica
    Milano, Italy
    INFN, Pavia, Italy
    Email: andrea.deluca@inaf.it

    Ruben Salvaterra
    INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica
    Milano, Italy
    Email: ruben.salvaterra@inaf.it

    Sandro Mereghetti
    INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica
    Milano, Italy
    Email: sandro.mereghetti@inaf.it

    Norbert Schartel
    XMM-Newton Project Scientist
    European Space Agency
    Email: norbert.schartel@esa.it

    Markus Bauer








    ESA Science and Robotic Exploration Communication Officer









    Tel: +31 71 565 6799









    Mob: +31 61 594 3 954









    Email: markus.bauer@esa.int

    1
    Flaring source in NGC 6540

    An enigmatic X-ray source revealed as part of a data-mining project for high-school students shows unexplored avenues hidden in the vast archive of ESA’s XMM-Newton X-ray Observatory.

    ESA/XMM Newton

    When XMM-Newton was launched in 1999, most students who are finishing high school today were not even born. Yet ESA’s almost two-decade old X-ray observatory has many surprises to be explored by the next generation of scientists.

    A taste of new discoveries was unveiled in a recent collaboration between scientists at the National Institute of Astrophysics (INAF) in Milan, Italy, and a group of twelfth-grade students from a secondary school in nearby Saronno.

    The fruitful interaction was part of the Exploring the X-ray Transient and variable Sky project, EXTraS, an international research study of variable sources from the first 15 years of XMM-Newton observations.

    “We recently published the EXTraS catalogue, which includes all the X-ray sources – about half a million – whose brightness changes over time as observed by XMM-Newton, and lists several observed parameters for each source,” says Andrea De Luca, one of the scientists who coordinated the student project.

    “The next step was to delve into this vast dataset and find potentially interesting sources, and we thought this would be an exciting challenge for a student internship.”

    2
    Flaring source in NGC 6540 . Animated.

    Scientists at INAF in Milan have been cooperating with local schools for a few years, hosting several groups of students at the institute for a couple of weeks and embedding them in the activities of the various research groups.

    “For this particular project, the students received an introduction about astronomy and the exotic sources we study with X-ray telescopes, as well as a tutorial on the database and how to use it,” explains Ruben Salvaterra, another scientist involved in the programme.

    “Once they were ready to explore the data archive, they proved very effective and resourceful.”

    The six students analysed about 200 X-ray sources, looking at their light curve – a graph showing the object’s variability over time – and checking the scientific literature to verify whether they had been studied already.

    Eventually, they identified a handful of sources exhibiting interesting properties – a powerful flare, for example – that had not been previously reported by other studies.

    “One of the sources stood out as especially intriguing,” says Andrea.

    Featuring the shortest flare of all analysed objects, this source appears to be located in the globular cluster NGC 6540 – a dense grouping of stars – and had not been studied before.

    2
    http://pegasus.cc.ucf.edu/~arecasc/globularclusterimage.html

    After presenting their findings to the scientists in a seminar, the students went back to school. But the work for Andrea, Ruben and collaborators had only just begun.

    “The source identified by the students displays brightness changes like no other known objects, so we started looking more in detail,” says Ruben.

    An otherwise low-luminosity source of X-rays, XMM-Newton saw it brighten by up to 50 times its normal level in 2005, and quickly fall again after about five minutes.

    Stars like our Sun shine moderately in X-rays, and occasionally undergo flares that boost their brightness like the one observed in this source. However, such events normally last much longer – up to a few hours or even days.

    On the other hand, short outbursts are observed in binary star systems hosting a dense stellar remnant such as neutron star, but these outpourings of X-rays are characterised by a much higher luminosity.

    “This event is challenging our understanding of X-ray outbursts: too short to be an ordinary stellar flare, but too faint to be linked to a compact object,” explains collaborator Sandro Mereghetti, lead author of the paper presenting the results.

    Another possibility is that the source is a so-called chromospherically active binary, a dual system of stars with intense X-ray activity caused by processes in their chromosphere, an intermediate layer in a star’s atmosphere. But even in this case, it does not closely match the properties of any known object of this class.

    The scientists suspect that this peculiar source is not unique, and that other objects with similar properties are lurking in the XMM-Newton archive but have not yet been identified because of the combination of low luminosity and short duration of the flare.

    “The systematic study of variability that led to the compilation of the EXTraS catalogue, together with this first attempt at data mining, suggests that we have opened a new, unexplored window on the X-ray Universe,” adds Sandro.

    The team plans to study the newly identified source in greater detail to better understand its nature, while searching for more similar objects in the archive.

    “It is exciting to find hidden jewels like this source in the XMM-Newton archive, and that young students are helping us find them while learning and having fun,” concludes Norbert Schartel, XMM-Newton project scientist at ESA.

    Science paper:
    EXTraS discovery of a peculiar flaring X-ray source in the Galactic globular cluster NGC 6540
    Astronomy & Astrophysics

    See the full article here .


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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 1:38 pm on June 16, 2018 Permalink | Reply
    Tags: , , , , , ESA/XMM-Newton, NGC 3199, , WR18 (Wolf-Rayet 18)   

    From European Space Agency: “Star-circling bubble of gas” 

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    From European Space Agency

    1
    Star-circling bubble of gas
    11/06/2018
    ESA/XMM-Newton; J. Toalá; D.Goldman

    ESA/XMM Newton

    This turbulent celestial palette of purple and yellow shows a bubble of gas named NGC 3199, blown by a star known as WR18 (Wolf-Rayet 18).

    Wolf-Rayet stars are massive, powerful, and energetic stars that are just about reaching the end of their lives. They flood their surroundings with thick, intense, fast-moving winds that push and sweep at the material found there, carving out weird and wonderful shapes as they do so. These winds can create strong shockwaves when they collide with the comparatively cool interstellar medium, causing them to heat up anything in their vicinity. This process can heat material to such high temperatures that it is capable of emitting X-rays, a type of radiation emitted only by highly energetic phenomena in the Universe.

    This is what has happened in the case of NGC 3199. Although this kind of scenario has been seen before, it is still relatively rare; only three other Wolf-Rayet bubbles have been seen to emit X-rays (NGC 2359, NGC 6888, and S308). WR18 is thought to be a star with especially powerful winds; once it has run out of material to fuel these substantial winds it will explode violently as a supernova, creating a final breath-taking blast as it ends its stellar life.

    This image was taken by the European Photon Imaging Camera (EPIC) on ESA’s XMM-Newton X-ray space observatory, and marks different patches of gas in different colours. The incredibly hot, diffuse, X-ray-emitting gas within the Wolf-Rayet bubble is shown in blue, while a bright arc that is visible in the optical part of the spectrum is traced out in shades of yellow-green (oxygen emission) and red (sulphur emission).

    This blue and yellow-green component forms an optical nebula – a glowing cloud of dust and ionised gases – that stretches out towards the western end of the X-ray bubble (in this image, North is to the upper left). This lopsided arc caused astronomers to previously identify WR18 as a so-called runaway star moving far faster than expected in relation to its surroundings, but more recent studies have shown that the observed X-ray emission does not support this idea. Instead, the shape of NGC 3199 is thought to be due to variations in the chemistry of the bubble’s surroundings, and the initial configuration of the interstellar medium around WR18.

    Explore this object in ESASky.

    See the full article here .


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    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 9:04 am on December 12, 2017 Permalink | Reply
    Tags: , , , , ESA/XMM-Newton,   

    From ESA: “Crescent nebula” 

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    European Space Agency

    1

    Crescent nebula
    Released 11/12/2017
    Copyright ESA/XMM-Newton, J. Toalá & D. Goldman

    ESA/XMM Newton X-ray telescope

    A young massive star that began life around 25 times more massive than our own Sun is shedding shells of material and fast winds to create this dynamic scene captured by ESA’s XMM-Newton.

    The image shows the detailed structure of the Crescent Nebula that shed a shell of material as it expanded into a red giant some 200 000 years ago. Fast winds emitted more recently have now collided with that material, causing the gasses in the bubble to heat up and emit X-rays, seen as blue in the image.

    Other features can also be seen, such as the green hue, generated by oxygen atoms, where the star’s wind is interacting with the surrounding interstellar medium.

    Density differences in the surrounding material may give rise to the different structures, such as the extended bubble segment to the top right.

    The star will likely end its life in a violent supernova explosion.

    The Crescent Nebula sits in the constellation of Cygnus about 5000 light-years away, exactly at a location in the sky that has not been accessible to XMM-Newton until recently. Although it has been well studied by other X-ray telescopes, astronomers working on XMM-Newton, which was launched on 10 December 1999, had to wait patiently until the orbit of the satellite was such that this patch of sky moved into its field of view in April 2014.

    More information about XMM-Newton’s observation is available in X-ray emission from the Wolf-Rayet bubble NGC 688. II. XMM-Newton EPIC observations, by J. Toalá et al. (2016).

    See the full article here .

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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 6:53 am on July 1, 2017 Permalink | Reply
    Tags: A Seyfert galaxy 2XMM J143450.5+033843, , , , , ESA/XMM-Newton,   

    From Hubble: “Hubble Eyes a Powerful Galaxy With a Password Name” 

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    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    June 30, 2017
    Editor: Karl Hille

    1

    Not all galaxies have the luxury of possessing a simple moniker or quirky nickname. This impressive galaxy imaged by the NASA/ESA Hubble Space Telescope is one of the unlucky ones, and goes by a name that looks more like a password for a computer: 2XMM J143450.5+033843.

    Such a name may seem like a random jumble of numbers and letters, but like all galactic epithets it has a distinct meaning. This galaxy, for example, was detected and observed as part of the second X-ray sky survey performed by ESA’s XMM-Newton Observatory.

    ESA/XMM Newton

    Its celestial coordinates form the rest of the bulky name, following the “J”: a right ascension value of 14h (hours) 34m (minutes) 50.5s (seconds). This can be likened to terrestrial longitude. It also has a declination of +03d (degrees) 38m (minutes) 43s (seconds). Declination can be likened to terrestrial latitude. The other fuzzy object in the frame was named in the same way — it is a bright galaxy named 2XMM J143448.3+033749.

    2XMM J143450.5+033843 lies nearly 400 million light-years away from Earth. It is a Seyfert galaxy that is dominated by something known as an Active Galactic Nucleus — its core is thought to contain a supermassive black hole that is emitting huge amounts of radiation, pouring energetic X-rays out into the Universe.

    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 5:37 am on May 16, 2017 Permalink | Reply
    Tags: , , , , Cygnus X-1, , ESA/XMM-Newton, Extra X-rays, Slew catalogue   

    From ESA: “Extra X-rays” 

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    European Space Agency

    Sources in XMM-Newton’s second slew catalogue

    ESA/XMM Newton

    1
    Sources in XMM-Newton’s second slew catalogue
    Released 15/05/2017
    Copyright ESA/XMM-Newton/ R. Saxton / A.M. Read, CC BY-SA 3.0 IGO

    This colourful, seemingly abstract artwork is actually a map depicting all the celestial objects that were detected in the XMM-Newton slew survey between August 2001 and December 2014.

    Orbiting Earth since 1999, XMM-Newton is studying high-energy phenomena in the Universe, such as black holes, neutron stars, pulsars and stellar winds. But even when moving between specific targets, the space telescope collects scientific data.

    The map shows the 30 000 sources captured during 2114 of these slews. Because of overlapping slew paths, some sources have been observed up to 15 times, and 4924 sources have been observed twice or more. After correcting for overlaps between slews, 84% of the sky has been covered.

    The plot is colour-coded such that sources of a lower energy are red and those with a higher energy are blue. In addition, the brighter the source, the larger it appears on the map.

    The plot is in galactic coordinates such that the centre of the plot corresponds to the centre of the Milky Way. High-energy sources along the centre of the Milky Way include the famous black hole Cygnus X-1, and Vela X-1, a binary system comprising a neutron star consuming matter from a supergiant companion.

    2
    http://snarkbot.net/post/133560858395/an-open-letter-to-binary-star-system-cygnus-x-1

    Several star-and-black hole binary systems are also captured, including objects identified as GRS 1915+105, 4U 1630-47 and V 4641 Sgr.

    Two clusters of sources, one to the top left and one to the bottom right, correspond to the ecliptic poles.

    Objects above and below the plane of our Galaxy are predominantly external galaxies that are emitting X-rays from their massive black holes.

    Technical information about the source catalogue is available here.

    See the full article here .

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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 5:00 pm on May 1, 2017 Permalink | Reply
    Tags: An Aging Pulsar has Captured a new Companion and it’s Spinning back up Again, , , , , ESA/XMM-Newton, Milliscond pulsar, Sternberg Astronomical Institute at Lomonosov Moscow State University (MSU), Ultra-slow pulsar,   

    From Universe Today: “An Aging Pulsar has Captured a new Companion, and it’s Spinning back up Again” 

    universe-today

    Universe Today

    1 May , 2017
    Matt Williams

    1
    No image caption. No image credit.

    When massive stars reach the end of their life cycle, they explode in a massive supernova and cast off most of their material. What’s left is a “milliscond pulsar”, a super dense, highly-magnetized neutron star that spins rapidly and emit beams of electromagnetic radiation. Eventually, these stars lose their rotational energy and begin to slow down, but they can speed up again with the help of a companion.

    According to a recent study, an international team of scientists witnessed this rare event when observing an ultra-slow pulsar located in the neighboring Andromeda Galaxy (XB091D). The results of their study indicated that this pulsar has been speeding up for the past one million years, which is likely the result of a captured a companion that has since been restoring its rapid rotational velocity.

    Typically, when a pulsars pairs with an ordinary star, the result is a binary system consisting of a pulsar and a white dwarf. This occurs after the pulsar pulls off the outer layers of a star, turning it into a white dwarf. The material from these outer layer then forms an accretion disk around the pulsar, which creates a “hot spot” that radiates brightly in the X-ray specturum and where temperatures can reach into the millions of degrees.

    The team was led by Ivan Zolotukhin of the Sternberg Astronomical Institute at Lomonosov Moscow State University (MSU), and included astronomers from the University of Toulouse, the National Institute for Astrophysics (INAF), and the Smithsonian Astrophysical Observatory. The study results were published in The Astrophysical Journal under the title The Slowest Spinning X-Ray Pulsar in an Extragalactic Globular Cluster.

    As they state in their paper, the detection of this pulsar was made possible thanks to data collected by the XMM-Newton space observatory from 2000-2013.

    ESA/XMM Newton

    In this time, XMM-Newton has gathered information on approximately 50 billion X-ray photons, which has been combined by astronomers at Lomosov MSU into an open online database.

    This database has allowed astronomers to take a closer look at many previously-discovered objects. This includes XB091D, a pulsar with a period of seconds (aka. a “second pulsar”) located in one of the oldest globular star clusters in the Andromeda galaxy. However, finding the X-ray photos that would allow them to characterize XB091D was no easy task. As Ivan Zolotukhin explained in a MSU press release:

    “The detectors on XMM-Newton detect only one photon from this pulsar every five seconds. Therefore, the search for pulsars among the extensive XMM-Newton data can be compared to the search for a needle in a haystack. In fact, for this discovery we had to create completely new mathematical tools that allowed us to search and extract the periodic signal. Theoretically, there are many applications for this method, including those outside astronomy.”

    2
    The slowest spinning X-ray pulsar in a globular star cluster has been discovered in the Andromeda galaxy. Credit: A. Zolotov

    Based on a total of 38 XMM-Newton observations, the team concluded that this pulsar (which was the only known pulsar of its kind beyond our galaxy at the time), is in the earliest stages of “rejuvenation”. In short, their observations indicated that the pulsar began accelerating less than 1 million years ago. This conclusion was based on the fact that XB091D is the slowest rotating globular cluster pulsar discovered to date.

    The neutron star completes one revolution in 1.2 seconds, which is more than 10 times slower than the previous record holder. From the data they observed, they were also able to characterize the environment around XB091D. For example, they found that the pulsar and its binary pair are located in an extremely dense globular cluster (B091D) in the Andromeda Galaxy – about 2.5 million light years away.

    This cluster is estimated to be 12 billion years old and contains millions of old, faint stars. It’s companion, meanwhile, is a 0.8 solar mass star, and the binary system itself has a rotation period of 30.5 hours. And in about 50,000 years, they estimate, the pulsar will accelerate sufficiently to once again have a rotational period measured in the milliseconds – i.e. a millisecond pulsar.

    4
    A diagram of the ESA XMM-Newton X-Ray Telescope. Delivered to orbit by a Ariane 5 launch vehicle in 1999. Credit: ESA/XMM-Newton

    Interestingly, XB910D’s location within this vast region of super-high density stars is what allowed it to capture a companion about 1 million years ago and commence the process “rejuvenation” in the first place. As Zolotukhin explained:

    “In our galaxy, no such slow X-ray pulsars are observed in 150 known globular clusters, because their cores are not big and dense enough to form close binary stars at a sufficiently high rate. This indicates that the B091D cluster core, with an extremely dense composition of stars in the XB091D, is much larger than that of the usual cluster. So we are dealing with a large and rather rare object—with a dense remnant of a small galaxy that the Andromeda galaxy once devoured. The density of the stars here, in a region that is about 2.5 light years across, is about 10 million times higher than in the vicinity of the Sun.”

    Thanks to this study, and the mathematical tools the team developed to find it, astronomers will likely be able to revisit many previously-discovered objects in the coming years. Within these massive data sets, there could be many examples of rare astronomical events, just waiting to be witnessed and properly characterized.

    See the full article here .

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