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  • richardmitnick 3:27 pm on July 23, 2019 Permalink | Reply
    Tags: , , , , , NASA Chandra   

    From NASA Chandra Blog: “Exploring New Paths of Study with Chandra” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra Blog

    Peter Edmonds, CXC

    We make progress in astrophysics in a variety of ways. There is the sort that starts along a defined path, driven by meticulous proposals for telescope time or detailed science justifications for new missions. The plan is to advance knowledge by traveling further than others, or clearing a broader path. And then there are others.

    A big mission like NASA’s Chandra X-ray Observatory begins with plans for investigation along a slew of different directions and lines of study. At the time of Chandra’s launch on July 23rd, 1999, scientists thought these paths would mainly follow studies of galaxy clusters, dark matter, black holes, supernovas, and young stars. Indeed, in the last 20 years we’ve learned about black holes ripping stars apart (reported eg in 2004, 2011 and 2017), about a black hole generating the deepest known note in the universe, about dark matter being wrenched apart from normal matter in the famous Bullet Cluster and similar objects, about the discovery of the youngest supernova remnant in our galaxy, and much more.

    Bullet Cluster NASA Chandra NASA ESA Hubble

    NASA/ESA Hubble Telescope

    Progress in astrophysics can also be made when new paths of study suddenly open up. Three outstanding examples for Chandra are studies of gravitational wave events, dark energy and exoplanets. None of these fields existed before Chandra was conceived or built, but have now delivered some of our most exciting results.

    Release: NASA Missions Catch FirstLight from a Gravitational-Wave Event

    The newest example is the study of X-rays produced by the aftermath of gravitational wave events. In 1999 the detection of gravitational waves seemed like a distant or even impossible goal for many astronomers. But the LIGO scientists kept improving their remarkably sensitive observatory until September 2015, when they detected a burst of gravitational waves from the merger of two black holes. Two black holes that merge are not expected to produce electromagnetic radiation, but the mergers of two neutron stars are. That is exactly what was as observed for the first time in August 2017 with LIGO and a slew of telescopes.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/eLISA the future of gravitational wave research

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2018

    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    UC Santa Cruz

    UC Santa Cruz

    UCSC All the Gold in the Universe

    A UC Santa Cruz special report

    Tim Stephens

    Astronomer Ryan Foley says “observing the explosion of two colliding neutron stars” –the first visible event ever linked to gravitational waves–is probably the biggest discovery he’ll make in his lifetime. That’s saying a lot for a young assistant professor who presumably has a long career still ahead of him.

    The first optical image of a gravitational wave source was taken by a team led by Ryan Foley of UC Santa Cruz using the Swope Telescope at the Carnegie Institution’s Las Campanas Observatory in Chile. This image of Swope Supernova Survey 2017a (SSS17a, indicated by arrow) shows the light emitted from the cataclysmic merger of two neutron stars. (Image credit: 1M2H Team/UC Santa Cruz & Carnegie Observatories/Ryan Foley)

    Carnegie Institution Swope telescope at Las Campanas, Chile, 100 kilometres (62 mi) northeast of the city of La Serena. near the north end of a 7 km (4.3 mi) long mountain ridge. Cerro Las Campanas, near the southern end and over 2,500 m (8,200 ft) high, at Las Campanas, Chile

    A neutron star forms when a massive star runs out of fuel and explodes as a supernova, throwing off its outer layers and leaving behind a collapsed core composed almost entirely of neutrons. Neutrons are the uncharged particles in the nucleus of an atom, where they are bound together with positively charged protons. In a neutron star, they are packed together just as densely as in the nucleus of an atom, resulting in an object with one to three times the mass of our sun but only about 12 miles wide.

    “Basically, a neutron star is a gigantic atom with the mass of the sun and the size of a city like San Francisco or Manhattan,” said Foley, an assistant professor of astronomy and astrophysics at UC Santa Cruz.

    These objects are so dense, a cup of neutron star material would weigh as much as Mount Everest, and a teaspoon would weigh a billion tons. It’s as dense as matter can get without collapsing into a black hole.


    Like other stars, neutron stars sometimes occur in pairs, orbiting each other and gradually spiraling inward. Eventually, they come together in a catastrophic merger that distorts space and time (creating gravitational waves) and emits a brilliant flare of electromagnetic radiation, including visible, infrared, and ultraviolet light, x-rays, gamma rays, and radio waves. Merging black holes also create gravitational waves, but there’s nothing to be seen because no light can escape from a black hole.

    Foley’s team was the first to observe the light from a neutron star merger that took place on August 17, 2017, and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO).


    It turns out that the origins of the heaviest elements, such as gold, platinum, uranium—pretty much everything heavier than iron—has been an enduring conundrum. All the lighter elements have well-explained origins in the nuclear fusion reactions that make stars shine or in the explosions of stars (supernovae). Initially, astrophysicists thought supernovae could account for the heavy elements, too, but there have always been problems with that theory, says Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz.

    The violent merger of two neutron stars is thought to involve three main energy-transfer processes, shown in this diagram, that give rise to the different types of radiation seen by astronomers, including a gamma-ray burst and a kilonova explosion seen in visible light. (Image credit: Murguia-Berthier et al., Science)

    A theoretical astrophysicist, Ramirez-Ruiz has been a leading proponent of the idea that neutron star mergers are the source of the heavy elements. Building a heavy atomic nucleus means adding a lot of neutrons to it. This process is called rapid neutron capture, or the r-process, and it requires some of the most extreme conditions in the universe: extreme temperatures, extreme densities, and a massive flow of neutrons. A neutron star merger fits the bill.

    Ramirez-Ruiz and other theoretical astrophysicists use supercomputers to simulate the physics of extreme events like supernovae and neutron star mergers. This work always goes hand in hand with observational astronomy. Theoretical predictions tell observers what signatures to look for to identify these events, and observations tell theorists if they got the physics right or if they need to tweak their models. The observations by Foley and others of the neutron star merger now known as SSS17a are giving theorists, for the first time, a full set of observational data to compare with their theoretical models.

    According to Ramirez-Ruiz, the observations support the theory that neutron star mergers can account for all the gold in the universe, as well as about half of all the other elements heavier than iron.


    Einstein predicted the existence of gravitational waves in 1916 in his general theory of relativity, but until recently they were impossible to observe. LIGO’s extraordinarily sensitive detectors achieved the first direct detection of gravitational waves, from the collision of two black holes, in 2015. Gravitational waves are created by any massive accelerating object, but the strongest waves (and the only ones we have any chance of detecting) are produced by the most extreme phenomena.

    Two massive compact objects—such as black holes, neutron stars, or white dwarfs—orbiting around each other faster and faster as they draw closer together are just the kind of system that should radiate strong gravitational waves. Like ripples spreading in a pond, the waves get smaller as they spread outward from the source. By the time they reached Earth, the ripples detected by LIGO caused distortions of space-time thousands of times smaller than the nucleus of an atom.

    The rarefied signals recorded by LIGO’s detectors not only prove the existence of gravitational waves, they also provide crucial information about the events that produced them. Combined with the telescope observations of the neutron star merger, it’s an incredibly rich set of data.

    LIGO can tell scientists the masses of the merging objects and the mass of the new object created in the merger, which reveals whether the merger produced another neutron star or a more massive object that collapsed into a black hole. To calculate how much mass was ejected in the explosion, and how much mass was converted to energy, scientists also need the optical observations from telescopes. That’s especially important for quantifying the nucleosynthesis of heavy elements during the merger.

    LIGO can also provide a measure of the distance to the merging neutron stars, which can now be compared with the distance measurement based on the light from the merger. That’s important to cosmologists studying the expansion of the universe, because the two measurements are based on different fundamental forces (gravity and electromagnetism), giving completely independent results.

    “This is a huge step forward in astronomy,” Foley said. “Having done it once, we now know we can do it again, and it opens up a whole new world of what we call ‘multi-messenger’ astronomy, viewing the universe through different fundamental forces.”


    Neutron stars
    A team from UC Santa Cruz was the first to observe the light from a neutron star merger that took place on August 17, 2017 and was detected by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)

    Graduate students and post-doctoral scholars at UC Santa Cruz played key roles in the dramatic discovery and analysis of colliding neutron stars.Astronomer Ryan Foley leads a team of young graduate students and postdoctoral scholars who have pulled off an extraordinary coup. Following up on the detection of gravitational waves from the violent merger of two neutron stars, Foley’s team was the first to find the source with a telescope and take images of the light from this cataclysmic event. In so doing, they beat much larger and more senior teams with much more powerful telescopes at their disposal.

    “We’re sort of the scrappy young upstarts who worked hard and got the job done,” said Foley, an untenured assistant professor of astronomy and astrophysics at UC Santa Cruz.

    David Coulter, graduate student

    The discovery on August 17, 2017, has been a scientific bonanza, yielding over 100 scientific papers from numerous teams investigating the new observations. Foley’s team is publishing seven papers, each of which has a graduate student or postdoc as the first author.

    “I think it speaks to Ryan’s generosity and how seriously he takes his role as a mentor that he is not putting himself front and center, but has gone out of his way to highlight the roles played by his students and postdocs,” said Enrico Ramirez-Ruiz, professor and chair of astronomy and astrophysics at UC Santa Cruz and the most senior member of Foley’s team.

    “Our team is by far the youngest and most diverse of all of the teams involved in the follow-up observations of this neutron star merger,” Ramirez-Ruiz added.

    Charles Kilpatrick, postdoctoral scholar

    Charles Kilpatrick, a 29-year-old postdoctoral scholar, was the first person in the world to see an image of the light from colliding neutron stars. He was sitting in an office at UC Santa Cruz, working with first-year graduate student Cesar Rojas-Bravo to process image data as it came in from the Swope Telescope in Chile. To see if the Swope images showed anything new, he had also downloaded “template” images taken in the past of the same galaxies the team was searching.

    Ariadna Murguia-Berthier, graduate student

    “In one image I saw something there that was not in the template image,” Kilpatrick said. “It took me a while to realize the ramifications of what I was seeing. This opens up so much new science, it really marks the beginning of something that will continue to be studied for years down the road.”

    At the time, Foley and most of the others in his team were at a meeting in Copenhagen. When they found out about the gravitational wave detection, they quickly got together to plan their search strategy. From Copenhagen, the team sent instructions to the telescope operators in Chile telling them where to point the telescope. Graduate student David Coulter played a key role in prioritizing the galaxies they would search to find the source, and he is the first author of the discovery paper published in Science.

    Matthew Siebert, graduate student

    “It’s still a little unreal when I think about what we’ve accomplished,” Coulter said. “For me, despite the euphoria of recognizing what we were seeing at the moment, we were all incredibly focused on the task at hand. Only afterward did the significance really sink in.”

    Just as Coulter finished writing his paper about the discovery, his wife went into labor, giving birth to a baby girl on September 30. “I was doing revisions to the paper at the hospital,” he said.

    It’s been a wild ride for the whole team, first in the rush to find the source, and then under pressure to quickly analyze the data and write up their findings for publication. “It was really an all-hands-on-deck moment when we all had to pull together and work quickly to exploit this opportunity,” said Kilpatrick, who is first author of a paper comparing the observations with theoretical models.

    César Rojas Bravo, graduate student

    Graduate student Matthew Siebert led a paper analyzing the unusual properties of the light emitted by the merger. Astronomers have observed thousands of supernovae (exploding stars) and other “transients” that appear suddenly in the sky and then fade away, but never before have they observed anything that looks like this neutron star merger. Siebert’s paper concluded that there is only a one in 100,000 chance that the transient they observed is not related to the gravitational waves.

    Ariadna Murguia-Berthier, a graduate student working with Ramirez-Ruiz, is first author of a paper synthesizing data from a range of sources to provide a coherent theoretical framework for understanding the observations.

    Another aspect of the discovery of great interest to astronomers is the nature of the galaxy and the galactic environment in which the merger occurred. Postdoctoral scholar Yen-Chen Pan led a paper analyzing the properties of the host galaxy. Enia Xhakaj, a new graduate student who had just joined the group in August, got the opportunity to help with the analysis and be a coauthor on the paper.

    Yen-Chen Pan, postdoctoral scholar

    “There are so many interesting things to learn from this,” Foley said. “It’s a great experience for all of us to be part of such an important discovery.”

    Enia Xhakaj, graduate student


    Scientific Papers from the 1M2H Collaboration

    Coulter et al., Science, Swope Supernova Survey 2017a (SSS17a), the Optical Counterpart to a Gravitational Wave Source

    Drout et al., Science, Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

    Shappee et al., Science, Early Spectra of the Gravitational Wave Source GW170817: Evolution of a Neutron Star Merger

    Kilpatrick et al., Science, Electromagnetic Evidence that SSS17a is the Result of a Binary Neutron Star Merger

    Siebert et al., ApJL, The Unprecedented Properties of the First Electromagnetic Counterpart to a Gravitational-wave Source

    Pan et al., ApJL, The Old Host-galaxy Environment of SSS17a, the First Electromagnetic Counterpart to a Gravitational-wave Source

    Murguia-Berthier et al., ApJL, A Neutron Star Binary Merger Model for GW170817/GRB170817a/SSS17a

    Kasen et al., Nature, Origin of the heavy elements in binary neutron star mergers from a gravitational wave event

    Abbott et al., Nature, A gravitational-wave standard siren measurement of the Hubble constant (The LIGO Scientific Collaboration and The Virgo Collaboration, The 1M2H Collaboration, The Dark Energy Camera GW-EM Collaboration and the DES Collaboration, The DLT40 Collaboration, The Las Cumbres Observatory Collaboration, The VINROUGE Collaboration & The MASTER Collaboration)

    Abbott et al., ApJL, Multi-messenger Observations of a Binary Neutron Star Merger


    Watch Ryan Foley tell the story of how his team found the neutron star merger in the video below. 2.5 HOURS.

    Press releases:

    UC Santa Cruz Press Release

    UC Berkeley Press Release

    Carnegie Institution of Science Press Release

    LIGO Collaboration Press Release

    National Science Foundation Press Release

    Media coverage:

    The Atlantic – The Slack Chat That Changed Astronomy

    Washington Post – Scientists detect gravitational waves from a new kind of nova, sparking a new era in astronomy

    New York Times – LIGO Detects Fierce Collision of Neutron Stars for the First Time

    Science – Merging neutron stars generate gravitational waves and a celestial light show

    CBS News – Gravitational waves – and light – seen in neutron star collision

    CBC News – Astronomers see source of gravitational waves for 1st time

    San Jose Mercury News – A bright light seen across the universe, proving Einstein right

    Popular Science – Gravitational waves just showed us something even cooler than black holes

    Scientific American – Gravitational Wave Astronomers Hit Mother Lode

    Nature – Colliding stars spark rush to solve cosmic mysteries

    National Geographic – In a First, Gravitational Waves Linked to Neutron Star Crash

    Associated Press – Astronomers witness huge cosmic crash, find origins of gold

    Science News – Neutron star collision showers the universe with a wealth of discoveries

    UCSC press release
    First observations of merging neutron stars mark a new era in astronomy


    Writing: Tim Stephens
    Video: Nick Gonzales
    Photos: Carolyn Lagattuta
    Header image: Illustration by Robin Dienel courtesy of the Carnegie Institution for Science
    Design and development: Rob Knight
    Project managers: Sherry Main, Scott Hernandez-Jason, Tim Stephens

    Dark Energy Survey

    Dark Energy Camera [DECam], built at FNAL

    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile, at an altitude of 7200 feet

    Noted in the video but not in the article:

    NASA/Chandra Telescope

    NASA/SWIFT Telescope

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA

    Prompt telescope CTIO Chile

    NASA NuSTAR X-ray telescope

    See the full article here

    A Chandra observation two days after the merger failed to make a detection, but about a week later a source was discovered. These and additional observations taught us about the behavior and orientation of the jet that the neutron star merger produced.

    The interest in this X-ray detection was so intense that there was a race between three different teams to publish the early Chandra observations first. This was accompanied by a rush to publicly announce the full set of results from LIGO and telescopes across the electromagnetic spectrum, before too many smart science writers dug out the news from Twitter and other publicly available information.

    Release: All in the Family: Kin ofGravitational-Wave Source Discovered

    Chandra detections of two likely neutron star mergers have been reported since August 2017 (in 2018 and 2019). These did not involve a detection of GWs, both because Advanced LIGO wasn’t yet operating, and because the events were likely too distant to be detectable even if it was. When Advanced LIGO and Virgo detect other neutron star mergers, and optical telescopes track them down, Chandra “Target of Opportunity” programs will kick in to study them. (TOOs, as they are called, are special cases made by scientists to interrupt the regularly scheduled observations in favor of one that is time sensitive and/or extremely important.) One is a large proposal and collaboration between three different teams, one aims to take a spectrum, another aims to observe a relatively nearby event, and a fourth involves joint observations with the VLA.

    Those who work on Chandra and many in the wider science community were very excited about this detection because it marked the first time that gravitational waves and electromagnetic radiation were observed together, as a new type of “multi-messenger” astrophysics. (Multi-messenger astrophysics involves at least two of the following messengers: electromagnetic radiation, gravitational waves, neutrinos and cosmic rays.) However, it did not represent the first instance of multi-messenger astrophysics, because both electromagnetic radiation and neutrinos had already been observed from the Sun and from Supernova 1987A. Chandra may have already got into the act with the observation of a flare from material very close to the supermassive black hole in the center of our Galaxy, as reported in 2014. An energetic neutrino observed with the IceCube detector may have originated from this flare.

    Another exciting new line of study has come from the discovery that the expansion of the universe is accelerating. The two key papers providing the first evidence for this surprising result were published in 1998 and 1999, just before Chandra launched. Both papers used distance measurements to supernova explosions over the last 5 billion or so years to follow the expansion. Since then a set of different techniques have been used to independently confirm and extend these results, including two involving Chandra observations of galaxy clusters. In one of them the distances to galaxy clusters were used to probe the expansion rate of the universe and another involved measuring the effects of accelerating expansion in slowing down the growth rate of galaxy clusters, in a type of cosmic arrested development. As explained in this article, if it wasn’t for accelerating expansion the universe would look very different from how it looks today.

    The work measuring the growth rate of galaxy clusters has led to independent tests of Einstein’s General Theory of Relativity over distances that are much greater than those of Earth-orbiting satellites. The confirmation of GR has added to the evidence that a mysterious force called “dark energy” is causing cosmic acceleration.

    Release: Astronomers Find Dark EnergyMay Vary Over Time

    More recently, Chandra is being used with a new technique to probe cosmic expansion out to greater distances than are possible with supernova data. Astronomers have found tentative evidence that dark energy might be strengthening with time, but this result needs to be confirmed with more extensive use of Chandra data, a study that is currently underway, and independent work.

    The recently-launched European mission eROSITA will be taking a sensitive X-ray survey of the complete sky and will discover a huge number of galaxy clusters for follow-up studies of both dark energy and dark matter with Chandra.

    eRosita DLR MPG

    Release: NASA’s Chandra Sees Eclipsing Planetin X-rays for First Time

    Many think the field of exoplanets studies started in 1995 with the detection of a hot Jupiter around the star 51 Pegasus, acclaimed as the first exoplanet discovered around a Sun-like star. (This was about the time that the grinding and polishing of Chandra’s grazing-incidence mirrors was completed.) Chandra observations have shown cases of the tail wagging the dog, where a planet is affecting the star it is orbiting, in one case by making the star appear unusually old, and in others causing it to behave like a much younger star, as reported in 2011 and 2013.

    Chandra observations have uncovered multiple examples of planets under assault by outside forces. They’ve found cases where radiation from the host star is evaporating the atmosphere of a close-in planet (from 2011 and 2013), where the powerful gravity of a white dwarf may have ripped a planet apart, a case of possible stellar or planetary cannibalism, and a case where a star may be devouring a young planet. Chandra data was also used to show that young stars much less massive than the Sun can unleash a torrent of X-ray radiation that may significantly shorten the lifetime of planet-forming disks surrounding these stars.

    We look forward to reporting more results in these three new fields, along with discoveries from X-ray astronomy’s traditional specialities. We also hope to see new fields appear, for fresh exploration with NASA’s premier X-ray mission.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 1:23 pm on July 23, 2019 Permalink | Reply
    Tags: , , , , NASA Chandra   

    From NASA Chandra (2): “NASA’s Chandra X-ray Observatory Celebrates Its 20th Anniversary” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra

    July 23, 2019
    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.

    Molly Porter
    Marshall Space Flight Center, Huntsville, Alabama

    Credit: NASA/CXC/SAO

    On July 23, 1999, the Space Shuttle Columbia blasted into space carrying NASA’s Chandra X-ray Observatory.

    Twenty years later, a collection of new images has been released to commemorate this milestone.

    Chandra observes many different types of astrophysical objects with the sharpest vision of any X-ray telescope.

    Along with the Hubble Space Telescope, Spitzer Space Telescope, and Compton Gamma Ray Observatory, Chandra is one of NASA’s “Great Observatories”.

    NASA/ESA Hubble Telescope

    NASA/Spitzer Infrared Telescope

    NASA Compton Gamma Ray Observatory

    To commemorate the 20th anniversary of NASA’s Chandra X-ray Observatory, an assembly of new images is being released. These images represent the breadth of Chandra’s exploration, demonstrating the variety of objects it studies as well as how X-rays complement the data collected in other types of light. Some of these images contain Chandra data exclusively and the rest show how X-rays fit with the different types of light that other telescopes collect.

    See the full article for images and descriptions here.

    “In this year of exceptional anniversaries — 50 years after Apollo 11 and 100 years after the solar eclipse that proved Einstein’s General Theory of Relativity — we should not lose sight of one more,” said Paul Hertz, Director of Astrophysics at NASA. “Chandra was launched 20 years ago, and it continues to deliver amazing science discoveries year after year.”

    Chandra is one of NASA’s “Great Observatories” (along with the Hubble Space Telescope, Spitzer Space Telescope, and Compton Gamma Ray Observatory), and has the sharpest vision of any X-ray telescope ever built. It is often used in conjunction with telescopes like Hubble and Spitzer that observe in different parts of the electromagnetic spectrum, and with other high-energy missions like the European Space Agency’s XMM-Newton and NASA’s NuSTAR.

    Chandra’s discoveries have impacted virtually every aspect of astrophysics. For example, Chandra was involved in a direct proof of dark matter’s existence. It has witnessed powerful eruptions from supermassive black holes. Astronomers have also used Chandra to map how the elements essential to life are spread from supernova explosions.

    Many of the phenomena Chandra now investigates were not even known when the telescope was being developed and built. For example, astronomers now use Chandra to study the effects of dark energy, test the impact of stellar radiation on exoplanets, and observe the outcomes of gravitational wave events.

    “Chandra remains peerless in its ability to find and study X-ray sources,” said Chandra X-ray Center Director Belinda Wilkes. “Since virtually every astronomical source emits X-rays, we need a telescope like Chandra to fully view and understand our Universe.”

    Chandra was originally proposed to NASA in 1976 by Riccardo Giacconi, recipient of the 2002 Nobel Prize for Physics based on his contributions to X-ray astronomy, and Harvey Tananbaum, who would become the first director of the Chandra X-ray Center. It took decades of collaboration — between scientists and engineers, private companies and government agencies, and more — to make Chandra a reality.

    “The building and operation of Chandra has always been and continues to be a team effort,” said Martin Weisskopf, Chandra Project Scientist of NASA’s Marshall Space Flight Center. “It’s been an honor and a privilege to be involved with this scientific powerhouse.”

    In 2018, NASA awarded a contract extension to continue operation and science support of Chandra through 2024, with the possibility of two three-year options.

    The Chandra X-ray Observatory was named in honor of the late Nobel laureate Subrahmanyan Chandrasekhar. NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science and flight operations from Cambridge, Mass.

    Other materials are available at:

    For more Chandra images, multimedia and related materials, visit:

    See the full article by Megan Watzke and Molly Porter here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 12:55 pm on July 3, 2019 Permalink | Reply
    Tags: , , , , , NASA Chandra,   

    From NASA Chandra: “X-rays Spot Spinning Black Holes Across Cosmic Sea” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra


    Quasars. Credit: NASA/CXC/Univ. of Oklahoma/X. Dai et al.

    Like whirlpools in the ocean, spinning black holes in space create a swirling torrent around them. However, black holes do not create eddies of wind or water. Rather, they generate disks of gas and dust heated to hundreds of millions of degrees that glow in X-ray light.

    Using data from NASA’s Chandra X-ray Observatory and chance alignments across billions of light years, astronomers have deployed a new technique to measure the spin of five supermassive black holes. The matter in one of these cosmic vortices is swirling around its black hole at greater than about 70% of the speed of light.

    The astronomers took advantage of a natural phenomenon called a gravitational lens.

    Gravitational Lensing NASA/ESA

    With just the right alignment, the bending of space-time by a massive object, such as a large galaxy, can magnify and produce multiple images of a distant object, as predicted by Einstein.

    In this latest research, astronomers used Chandra and gravitational lensing to study five quasars, each consisting of a supermassive black hole rapidly consuming matter from a surrounding accretion disk. Gravitational lensing of the light from each of these quasars by an intervening galaxy has created multiple images of each quasar, as shown by these Chandra images of four of the targets. The sharp imaging ability of Chandra is needed to separate the multiple, lensed images of each quasar.

    The key advance made by researchers in this study was that they took advantage of “microlensing,” where individual stars in the intervening, lensing galaxy provided additional magnification of the light from the quasar.

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

    A higher magnification means a smaller region is producing the X-ray emission.

    The researchers then used the property that a spinning black hole is dragging space around with it and allows matter to orbit closer to the black hole than is possible for a non-spinning black hole. Therefore, a smaller emitting region corresponding to a tight orbit generally implies a more rapidly spinning black hole. The authors concluded from their microlensing analysis that the X-rays come from such a small region that the black holes must be spinning rapidly.

    The results showed that one of the black holes, in the lensed quasar called the “Einstein Cross,” (labeled Q2237 in the image above) is spinning at, or almost at, the maximum rate possible. This corresponds to the event horizon, the black hole’s point of no return, spinning at the speed of light, which is about 670 million miles per hour. Four other black holes in the sample are spinning, on average, at about half this maximum rate.

    For the Einstein Cross the X-ray emission is from a part of the disk that is less than about 2.5 times the size of the event horizon, and for the other 4 quasars the X-rays come from a region four to five times the size of the event horizon.

    How can these black holes spin so quickly? The researchers think that these supermassive black holes likely grew by accumulating most of their material over billions of years from an accretion disk spinning with a similar orientation and direction of spin, rather than from random directions. Like a merry-go-round that keeps getting pushed in the same direction, the black holes kept picking up speed.

    The X-rays detected by Chandra are produced when the accretion disk surrounding the black hole creates a multimillion-degree cloud, or corona above the disk near the black hole. X-rays from this corona reflect off the inner edge of the accretion disk, and the strong gravitational forces near the black hole distort the reflected X-ray spectrum, that is, the amount of X-rays seen at different energies. The large distortions seen in the X-ray spectra of the quasars studied here imply that the inner edge of the disk must be close to the black holes, giving further evidence that they must be spinning rapidly.

    The quasars are located at distances ranging from 9.8 billion to 10.9 billion light years from Earth, and the black holes have masses between 160 and 500 million times that of the sun. These observations were the longest ever made with Chandra of gravitationally lensed quasars, with total exposure times ranging between 1.7 and 5.4 days.

    A paper describing these results is published in the July 2nd issue of The Astrophysical Journal. The authors are Xinyu Dai, Shaun Steele and Eduardo Guerras from the University of Oklahoma in Norman, Oklahoma, Christopher Morgan from the United States Naval Academy in Annapolis, Maryland, and Bin Chen from Florida State University in Tallahassee, Florida.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

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

  • richardmitnick 8:20 am on July 2, 2019 Permalink | Reply
    Tags: "Meet The Largest X-Ray Jet In The Universe", , , , , , NASA Chandra, The active galaxy Pictor A   

    From Ethan Siegel: “Meet The Largest X-Ray Jet In The Universe” 

    From Ethan Siegel
    July 1, 2019

    Discovered by NASA’s Chandra X-ray observatory, it’s powered by a supermassive black hole.

    2019 marks 20 years of NASA’s Chandra, humanity’s most powerful X-ray observatory.

    Artist illustration of the Chandra X-ray Observatory. Chandra is the most sensitive X-ray telescope ever built, and its mission was extended through at least 2024 as the flagship X-ray observatory in the NASA arsenal. (NASA/CXC/NGST TEAM)

    It’s viewed everything from pulsars to colliding gas to galaxy clusters and supermassive black holes.

    A map of the 7 million second exposure of the Chandra Deep Field-South. This region shows hundreds of supermassive black holes, each one in a galaxy far beyond our own. The GOODS-South field, a Hubble project, was chosen to be centered on this original image. Its view of supermassive black holes is only one incredible application of the NASA’s Chandra X-ray observatory. (NASA/CXC/B. LUO ET AL., 2017, APJS, 228, 2)

    In 2015, it set its sights on a galaxy some 485 million light-years away: the radio-loud behemoth known as Pictor A.

    The jet of the active galaxy Pictor A, with X-rays in blue and radio lobes in pink. When galaxies merge together, they’re expected to activate similarly to how this one has. (X-RAY: NASA/CXC/UNIV OF HERTFORDSHIRE/M.HARDCASTLE ET AL., RADIO: CSIRO/ATNF/ATCA)

    When Chandra took a look at it with its X-ray eyes, it saw something unprecendented and spectacular: a jet 300,000 light-years long.

    The X-ray (B&W) and radio (red contours) emissions from the galaxy Pictor A. The greyscale image shows all the X-rays emitted with 500 to 5000 eV of energy, more than enough to ionize any atoms or molecules it encounters. The red contours are radio data shown superimposed atop the X-ray data. (M.J. HARDCASTLE ET AL. (2015), FROM ARXIV.ORG/ABS/1510.08392)

    Like all known active galaxies, Pictor A is powered by a supermassive black hole many millions to billions of times our Sun’s mass.

    The galaxy Centaurus A is the closest example of an active galaxy to Earth, with its high-energy jets caused by electromagnetic acceleration around the central black hole. The extent of its jets are far smaller than the jets that Chandra has observed around Pictor A. (NASA/CXC/CFA/R.KRAFT ET AL.)

    Black holes can accelerate and eject infalling matter, leading to intense emissions.

    A black hole more than six billion times the mass of the Sun powers the X-ray jet at the center of M87, which is many thousands of light-years in extent. If this image looks familiar, it might be: M87 is the first galaxy to have its event horizon imaged directly, owing to the incredible collaborative work of scientists working on the Event Horizon Telescope. (NASA/HUBBLE/WIKISKY)

    The light released spans the spectrum from high-energy X-rays to low-energy radio waves.

    Appearing on a scale far greater than the scale of the galaxy itself, the jet emitted from Pictor A can be seen in the data at various points, thanks to the interactions between these high-energy emissions and the gas in the surrounding environment of the galaxy itself. The ‘hot spot’ at the end of the jet can be seen at the far right of the upper view of this image. (M.J. HARDCASTLE ET AL. (2015), FROM ARXIV.ORG/ABS/1510.08392)

    The radio lobes of gas provide a medium for high-energy X-rays to interact with.

    While distant host galaxies for quasars and active galactic nuclei can often be imaged in visible/infrared light, the jets themselves and the surrounding emission is best viewed in both the X-ray and the radio, as illustrated here for the galaxy Hercules A. The gaseous outflows are highlighted in the radio, and if X-ray emissions follow the same path into the gas, they can be responsible for creating hot spots owing to the acceleration of electrons. (NASA, ESA, S. BAUM AND C. O’DEA (RIT), R. PERLEY AND W. COTTON (NRAO/AUI/NSF), AND THE HUBBLE HERITAGE TEAM (STSCI/AURA))

    When these interactions cause electrons to exceed the speed of sound in the gaseous medium, it creates intense shock waves.

    An annotated version of the X-ray/radio composite image of Pictor A, showing the counterjet, the Hot Spot, and many other fascinating features. (X-RAY: NASA/CXC/UNIV OF HERTFORDSHIRE/M.HARDCASTLE ET AL., RADIO: CSIRO/ATNF/ATCA)

    The “hot spot” illustrated on the above NASA image is the definitive evidence of the jet-like nature of these X-rays and accelerated electrons.

    Artist’s impression of an active galactic nucleus. The supermassive black hole at the center of the accretion disk sends a narrow high-energy jet of matter into space, perpendicular to the disc. A blazar about 4 billion light years away is the origin of many of the highest-energy cosmic rays and neutrinos, but even the full suite of active galaxies cannot compete with Pictor A in terms of raw size of the X-ray jet. (DESY, SCIENCE COMMUNICATION LAB)

    Alternative explanations involving boosted CMB photons have been ruled out.

    The most distant X-ray jet in the Universe, from quasar GB 1428, located 12.4 billion light years from Earth. This jet comes from electrons heating CMB photons, but that mechanism is ruled out for Pictor A. (X-RAY: NASA/CXC/NRC/C.CHEUNG ET AL; OPTICAL: NASA/STSCI; RADIO: NSF/NRAO/VLA)

    Pictor A possesses the largest X-ray jet in the known Universe.

    Despite many years of observations, we still don’t know whether the galaxy Pictor A, shown as viewed in optical light (main) and ultraviolet light (inset), is a spiral, elliptical, or irregular galaxy. Superior observations of the galaxy itself have yet to be acquired. (DIGITIZED SKY SURVEY 2 (MAIN); NASA/GALEX (INSET))

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

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

  • richardmitnick 2:29 pm on June 25, 2019 Permalink | Reply
    Tags: "Galaxy Clusters Caught in a First Kiss", , , , , , Giant Metrewave Radio Telescope, JAXA/Suzaku satellite, NASA Chandra, SDSS Telescope at Apache Point Observatory, SKA LOFAR core near Exloo Netherlands   

    From NASA Chandra: “Galaxy Clusters Caught in a First Kiss” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra

    June 25, 2019
    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.





    Credit: X-ray: NASA/CXC/RIKEN/L. Gu et al; Radio: NCRA/TIFR/GMRT; Optical: SDSS
    Press Image, Caption, and Videos

    Giant Metrewave Radio Telescope, an array of thirty telecopes, located near Pune in India

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

    For the first time, astronomers have found two giant clusters of galaxies that are just about to collide. This observation can be seen as a missing ‘piece of the puzzle’ in our understanding of the formation of structure in the Universe, since large-scale structures—such as galaxies and clusters of galaxies—are thought to grow by collisions and mergers. The result was published in Nature Astronomy on June 24th, 2019 and used data from NASA’s Chandra X-ray Observatory and other X-ray missions.

    Clusters of galaxies are the largest known bound objects and consist of hundreds of galaxies that each contain hundreds of billions of stars. Ever since the Big Bang, these objects have been growing by colliding and merging with each other. Due to their large size, with diameters of a few million light years, these collisions can take about a billion years to complete. Eventually the two colliding clusters will have merged into one bigger cluster.

    Because the merging process takes much longer than a human lifetime, we only see snapshots of the various stages of these collisions. The challenge is to find colliding clusters that are just at the stage of first touching each other.


    In theory, this stage has a relatively short duration and is therefore hard to find. It is like finding a raindrop that just touches the water surface in a photograph of a pond during a rain shower. Obviously, such a picture would show a lot of falling droplets and ripples on the water surface, but only few droplets in the process of merging with the pond. Similarly, astronomers found a lot of single clusters and merged clusters with outgoing ripples indicating a past collision, but until now no two clusters that are just about to touch each other.

    An international team of astronomers now announced the discovery of two clusters on the verge of colliding. This enabled astronomers to test their computer simulations, which show that in the first moments a shock wave, analogous to the sonic boom produced by supersonic motion of an airplane, is created in between the clusters and travels out perpendicular to the merging axis. “These clusters show the first clear evidence for this type of merger shock,” says first author Liyi Gu from RIKEN national science institute in Japan and SRON Netherlands Institute for Space Research. “The shock created a hot belt region of 100-million-degree gas between the clusters, which is expected to extend up to, or even go beyond the boundary of the giant clusters. Therefore, the observed shock has a huge impact on the evolution of galaxy clusters and large scale structures.”

    Astronomers are planning to collect more ‘snapshots’ to ultimately build up a continuous model describing the evolution of cluster mergers. SRON-researcher Hiroki Akamatsu: “More merger clusters like this one will be found by eROSITA, an X-ray all-sky survey mission that will be launched this year.

    eRosita DLR MPG

    Two other upcoming X-ray missions, XRISM and Athena, will help us understand the role of these colossal merger shocks in the structure formation history.”

    JAXA XRSM spacecraft schematic

    ESA Athena

    Liyi Gu and his collaborators studied the colliding pair during an observation campaign, carried out with three X-ray satellites (ESA’s XMM-Newton satellite, NASA’s Chandra, and JAXA’s Suzaku satellite) and two radio telescopes (the Low-Frequency Array, a European project led by the Netherlands, and the Giant Metrewave Radio Telescope operated by National Centre for Radio Astrophysics of India).

    ESA/XMM Newton

    JAXA/Suzaku satellite

    SKA LOFAR core (“superterp”) near Exloo, Netherlands

    Other materials about the findings are available at:

    For more Chandra images, multimedia and related materials, visit:

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

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

  • richardmitnick 2:18 pm on June 18, 2019 Permalink | Reply
    Tags: "Does the Gas in Galaxy Clusters Flow Like Honey?", , , , , NASA Chandra   

    From NASA Chandra: “Does the Gas in Galaxy Clusters Flow Like Honey?” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra

    June 18, 2019
    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.

    Credit: X-ray: NASA/CXC/Univ. of Chicago, I. Zhuravleva et al, Optical: SDSS
    Press Image, Caption, and Videos

    We have seen intricate patterns that milk makes in coffee and much smoother ones that honey makes when stirred with a spoon. Which of these cases best describes the behavior of the hot gas in galaxy clusters? By answering this question, a new study using NASA’s Chandra X-ray Observatory has deepened our understanding of galaxy clusters, the largest structures in the Universe held together by gravity.

    Galaxy clusters are comprised of three main components: individual galaxies, multimillion-degree gas that fills the space between the galaxies, and dark matter, a mysterious form of matter that is spread throughout a cluster and accounts for about 80 percent of the mass of the cluster.

    A team of astronomers used a set of long Chandra observations, totaling about two weeks of observing, of the Coma galaxy cluster to probe gas properties on spatial scales comparable with a typical distance that particles travel between collisions with each other. This measurement helped them to learn about the viscosity — the technical term for the resistance to the motion of gas lumps with respect to each other — of the hot gas in Coma.

    “Our finding suggests that gas viscosity in Coma is much lower than expected,” said Irina Zhuravleva of the University of Chicago, who led the study. “This means that turbulence can easily develop in the hot gas in galaxy clusters on small scales, analogous to swirling motions in a coffee mug”.

    The hot gas in Coma glows in X-ray light observed by Chandra. The gas is known to contain about six times more mass than all of the combined galaxies in the cluster. Despite its abundance, the density of the hot gas in Coma, which radio observations have shown is permeated by a weak magnetic field, is so low that the particles do not interact with each other very often. Such a low-density, hot gas cannot be studied in a laboratory on Earth, and so scientists must rely on cosmic laboratories such as the one provided by the intergalactic gas in Coma.

    “We used Chandra to probe whether the density of the gas is smooth on the smallest scales we can detect,” said Eugene Churazov, a co-author from the Max Planck Institute for Astrophysics in Garching and the Space Research Institute in Moscow. “We found that it is not, suggesting that turbulence is present even on these relatively small scales and the viscosity is low.”

    To reach these conclusions, the team concentrated on a region away from the center of the Coma Cluster where the density of the hot gas is even lower than it is in the center. Here, the particles have to travel longer distances — about 100,000 light years on average — to interact with another particle. This distance is large enough to be probed with Chandra.

    “Perhaps one of the most surprising aspects is that we were able to study physics on scales relevant to interactions between atomic particles in an object that’s 320 million light years away,” said co-author Alexander Schekochihin of the University of Oxford in the United Kingdom. “Such observations open a great opportunity to use galaxy clusters as laboratories to study fundamental properties of hot gas.”

    Why is the viscosity of Coma’s hot gas so low? One explanation is the presence of small-scale irregularities in the cluster’s magnetic field. These irregularities can deflect particles in the hot gas, which is composed of electrically charged particles, mostly electrons, and protons. These deflections reduce the distance a particle can move freely and, by extension, the gas viscosity.

    Knowledge of the viscosity of gas in a galaxy cluster and how easily turbulence develops helps scientists understand the effects of important phenomena such as collisions and mergers with other galaxy clusters, and galaxy groups. Turbulence generated by these powerful events can act as a source of heat, preventing the hot gas in clusters from cooling to form billions of new stars.

    The researchers chose the Coma cluster for this study because it has the best combination of physical properties required. The average distance between particle collisions is higher for gas with hotter temperatures and lower densities. Coma is hotter than other brightest nearby galaxy clusters and has relatively low density, unlike cool and dense cores of other bright galaxy clusters including Perseus and Virgo. This gives astronomers a chance to use the Coma cluster as a laboratory for studying plasma physics.

    Future direct measurements of velocities of gas motions with the X-ray Imaging and Spectroscopy Mission (XRISM), a collaborative mission between the Japanese Exploration Agency and NASA, will provide more details on cluster dynamics, allowing us to make robust studies of many nearby galaxy clusters. XRISM is expected to launch in the early 2020s.

    A paper describing this result appeared in the June 17th issue of the journal Nature Astronomy and is available online.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 7:16 pm on June 3, 2019 Permalink | Reply
    Tags: "Heart of Lonesome Galaxy is Brimming with Dark Matter", , , , , NASA Chandra   

    From NASA Chandra: “Heart of Lonesome Galaxy is Brimming with Dark Matter” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra

    June 3, 2019

    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.

    Credit: X-ray: NASA/CXC/Univ. of CA Irvine/D. Buote; Optical: NASA/STScI

    Isolated for billions of years, a galaxy with more dark matter packed into its core than expected has been identified by astronomers using data from NASA’s Chandra X-ray Observatory.

    The galaxy, known as Markarian 1216 (abbreviated as Mrk 1216), contains stars that are within 10% the age of the universe — that is, almost as old as the universe itself. Scientists have found that it has gone through a different evolution than typical galaxies, both in terms of its stars and the invisible dark matter that, through gravity, holds the galaxy together. Dark matter accounts for about 85% of the matter in the universe, although it has only been detected indirectly.

    Mrk 1216 belongs to a family of elliptically shaped galaxies that are more densely packed with stars in their centers than most other galaxies. Astronomers think they have descended from reddish, compact galaxies called “red nuggets” that formed about a billion years after the big bang, but then stalled in their growth about 10 billion years ago.

    If this explanation is correct, then the dark matter in Mark 1216 and its galactic cousins should also be tightly packed. To test this idea for the first time, a pair of astronomers studied the X-ray brightness and temperature of hot gas at different distances from Mrk 1216’s center, so they could “weigh” how much dark matter exists in the middle of the galaxy.

    “When we compared the Chandra data to our computer models, we found a much stronger concentration of dark matter was required than we find in other galaxies of similar total mass,” said David Buote of the University of California at Irvine. “This tells us the history of Mrk 1216 is very different from the typical galaxy. Essentially all of its stars and dark matter was assembled long ago with little added in the past 10 billion years.”

    According to the new study, a halo, or fuzzy sphere, of dark matter formed around the center of Mrk 1216 about 3 or 4 billion years after the big bang. This halo is expected to have extended over a larger region than the stars in the galaxy. The formation of such a red nugget galaxy was typical for a wide range of elliptical galaxies seen today. However, unlike Mrk 1216, most giant elliptical galaxies continued to gradually grow in size when smaller galaxies merged with them over cosmic time.

    “The old ages and dense concentration of the stars in compact elliptical galaxies like Mrk 1216 seen relatively nearby provided the first key evidence that they are the descendants of the red nuggets seen at great distances”, said co-author Aaron Barth, also of the University of California at Irvine. “We think the compact size of the dark matter halo seen here clinches the case.”

    Previously, astronomers estimated that the supermassive black hole in Mrk 1216 is more massive than expected for a galaxy of its mass. This most recent study, however, concluded that the black hole is likely to weigh less than about 4 billion times the mass of the Sun. That sounds like a lot, but it may not be unusually massive for a galaxy as large as Mrk 1216.

    The authors also searched for signs of outbursts from the supermassive black hole in the center of the galaxy. They saw hints of cavities in the hot gas similar to those observed in other massive galaxies and galaxy clusters like Perseus, but more data are needed to confirm their presence.

    The Mrk 1216 data also provide useful information about dark matter. Because dark matter has never been directly observed, some scientists question whether it exists at all. In the study, Buote and Barth interpreted the Chandra data using both standard, “Newtonian” models of gravity and an alternative theory known as modified Newtonian dynamics, or “MOND” designed to remove the need for dark matter in typical galaxies. The results showed that both theories of gravity required about the same extraordinary amount of dark matter in the center of Mrk 1216, effectively removing the need for the MOND explanation.

    “In the future we hope to go a step further and study the nature of dark matter,” said Buote. “The dense accumulation of dark matter in the middle of Mrk 1216 may provide an interesting test for non-standard theories that predict less centrally concentrated dark matter, such as for dark matter particles that interact with each other by an additional means other than gravity.”

    A paper describing these results appeared in the June 1st, 2019 issue of The Astrophysical Journal.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 10:05 am on June 2, 2019 Permalink | Reply
    Tags: "A Giant Stellar Eruption Detected for the First Time", , , , , NASA Chandra   

    From NASA Chandra: “A Giant Stellar Eruption Detected for the First Time” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra

    May 31, 2019
    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.


    A group of researchers has identified and characterized for the first time in a complete way a powerful eruption in the atmosphere of the active star HR 9024, marked by an intense flash of X-rays followed by the emission of a giant bubble of plasma, ie hot gas containing charged particles. This is the first time a coronal mass ejection, or CME, has been seen in a star other than our Sun. The corona is the outer atmosphere of a star.

    The work, appearing in an article in the latest issue of the journal Nature Astronomy, used data collected by NASA’s Chandra X-ray Observatory. The results confirm that CMEs are produced in magnetically active stars and are relevant to stellar physics, and they also open the opportunity to systematically study such dramatic events in stars other than the Sun.

    “The technique we used is based on monitoring the velocity of plasmas during a stellar flare,” said Costanza Argiroffi (University of Palermo in Italy and associate researcher at the National Institute for Astrophysics in Italy) who led the study. “This is because, in analogy with the solar environment, it is expected that, during a flare, the plasma confined in the coronal loop where the flare takes place moves first upward, and then downwards reaching the lower layers of the stellar atmosphere. Moreover, there is also expected to be an additional motion, always directed upwards, due to the CME associated with the flare”.

    The team analyzed a particularly favorable flare, which took place on the active star HR 9024, about 450 light-years away from us. The High-Energy Transmission Grating Spectrometer, or HETGS, aboard Chandra is the only instrument that allows measurements of the motions of coronal plasmas with speeds of just a few tens of thousands of miles per hour.

    The results of this observation clearly show that, during the flare, very hot material (between 18 to 45 million degrees Fahrenheit) first rises and then drops with speeds between 225,000 to 900,000 miles per hour. This is in excellent agreement with the expected behavior for the material linked to the stellar flare.

    “This result, never achieved before, confirms that our understanding of the main phenomena that occur in flares is solid,” said Argiroffi. “We were not so confident that our predictions could match in such a way with observations, because our understanding of flares is based almost completely on observations of the solar environment, where the most extreme flares are even a hundred thousand times less intense in the X-radiation emitted”.

    “The most important point of our work, however, is another: we found, after the flare, that the coldest plasma — at a temperature of ‘only’ seven million degrees Fahrenheit — rose from the star, with a constant speed of about 185,000 miles per hour,” said Argiroffi. “And these data are exactly what one would have expected for the CME associated with the flare.”

    The Chandra data allowed, in addition to the speed, the mass of the studied CME to be obtained, equal to two billion billion pounds, about ten thousand times greater than the most massive CMEs launched into interplanetary space by the Sun, in agreement with the idea that the CMEs in active stars are larger-scale versions of solar CMEs. The observed speed of the CME, however, is significantly lower than expected. This suggests that the magnetic field in the active stars is probably less efficient in accelerating CMEs than the solar magnetic field.

    These results have been published in the most recent issue of Nature Astronomy. The co-authors of the paper are Fabio Reale from the University of Palermo in Palermo, Italy, Jeremy Drake from the Center for Astrophysics | Harvard and Smithsonian (CfA), Angela Ciaravella from the National Institute for Astrophysics (INAF) in Palermo, Paola Testa from CfA, Rosaria Bonito from INAF in Palermo, Marco Miceli from the University of Palermo, Salvatore Orlando from INAF in Palermo and Giovanni Peres from the University of Palermo.

    Other materials about the findings are available at:

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 1:20 pm on May 28, 2019 Permalink | Reply
    Tags: , , , , NASA Chandra, NGC 1399 and NGC 1404 two of the largest galaxies in the Fornax galaxy cluster   

    From NASA Chandra: “Chandra Finds Stellar Duos Banished from Galaxies” 

    NASA Chandra Banner

    NASA/Chandra Telescope

    From NASA Chandra


    Media contacts:
    Megan Watzke
    Chandra X-ray Center, Cambridge, Mass.

    This image from NASA’s Chandra X-ray Observatory shows the region around NGC 1399 and NGC 1404, two of the largest galaxies in the Fornax galaxy cluster. Credit: X-ray: NASA/CXC/Nanjing University/X. Jin et al.

    Fornax cluster of galaxies, and lies about 60 million light-years from Earth.

    This image from NASA’s Chandra X-ray Observatory shows the region around NGC 1399 and NGC 1404, two of the largest galaxies in the Fornax galaxy cluster. Located at a distance of about 60 million light years, Fornax is one of the closest galaxy clusters to Earth. This relative proximity allows astronomers to study the Fornax cluster in greater detail than most other galaxy clusters.

    A new study is an example of what can be achieved when telescopes like Chandra study the Fornax cluster for long periods of time. By combining 15 days’ worth of Chandra observing of Fornax spread out between 1999 and 2015, astronomers discovered that pairs of stars had been expelled the galaxies in the cluster.

    Astronomers refer to pairs of stars orbiting around each other as a “binary” or “binary system.” These stellar pairs can consist of combinations of stars like our Sun, or more exotic and denser varieties such as neutron stars or even black holes. Neutron stars form when a massive star explodes as a supernova and the core of the star collapses onto itself. Under certain conditions, these gargantuan blasts are not symmetric. The recoil caused by this asymmetry can kick the star with such force that it is expelled from the galaxy where it resides. These new Chandra results show that sometimes a neutron star’s companion star is forced to exit the galaxy as well.

    While this image shows point-like sources in addition to more diffuse X-ray emission detected by Chandra, it is not possible to identify which of these sources may be the expelled binaries. The reason for this is that the authors employed a statistical methodology to determine that 30 out of the nearly 1,200 X-ray sources, associated with 29 galaxies in the Fornax cluster, were likely to be pairs of stars that had been kicked out of the center of their host galaxies.

    In addition to these banished X-ray binaries, the researchers found about 150 other sources located outside the boundaries of the galaxies observed by Chandra. One possible explanation for these sources is that they reside in the halos, or far outer reaches, of the Fornax cluster’s central galaxy, where they were formed. Another option is that they are X-ray binaries that were pulled away from a galaxy by the gravitational force of a nearby galaxy during a flyby, or X-ray binaries left behind as part of the remnants of a galaxy stripped of most of its stars by a galactic collision. Such interactions are expected to be relatively common in a crowded region like the one in the Fornax cluster.

    A paper describing these results appears in the May 1st, 2019 issue of The Astrophysical Journal and is available online. The authors of the paper are Xiangyu Jin, Meicun Hou, Zhenlin Zhu, and Zhiyuan Li of Nanjing University in China.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    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 12:11 pm on May 7, 2019 Permalink | Reply
    Tags: "Storm in the Teacup quasar", , , , , , , NASA Chandra,   

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

    ESA Space For Europe Banner

    From European Space Agency


    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 .

    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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