Tag Archives: Chandra X-ray Observatory

NASA Memory Lane (39)

July 23, 1999.

Fifteen Years Ago, Chandra X-Ray Observatory Deployed by Space Shuttle Crew
Fifteen Years Ago, Chandra X-Ray Observatory Deployed by Space Shuttle Crew
NASA – On July 23, 1999, a little more than seven hours after Space Shuttle Columbia and its five astronauts were launched from the Kennedy Space Center, NASA’s Chandra X-Ray Observatory was successfully deployed by the STS-93 crew. Chandra was spring-ejected from a cradle in the shuttle’s cargo bay at 6:47 a.m. Central time, as Columbia flew over the Indonesian island chain. Commander Eileen Collins, the first female Shuttle Commander, maneuvered Columbia to a safe distance away from the telescope as an internal timer counted down to the first of a two-phase ignition of the solid-fuel Inertial Upper Stage (IUS). The IUS lit up as scheduled at 7:47 a.m., and a few minutes later, shut down as planned, sending Chandra on a highly elliptical orbit which was refined over the next few weeks by a series of firings of telescope thrusters, designed to place Chandra in an orbit about 6900 x 87,000 statute miles above the Earth.

Since its deployment, Chandra has helped revolutionize our understanding of the universe through its unrivaled X-ray vision. Chandra, one of NASA’s current “Great Observatories,” along with the Hubble Space Telescope and Spitzer Space Telescope, is specially designed to detect X-ray emission from hot and energetic regions of the universe.

In this photograph, the five STS-93 astronauts pose for the traditional inflight crew portrait on Columbia’s middeck. In front are astronauts Eileen M. Collins, mission commander, and Michel Tognini, mission specialist representing France’s Centre National d’Etudes Spatiales (CNES). Behind them are (from the left) astronauts Steven A. Hawley, mission specialist; Jeffrey S. Ashby, pilot; and Catherine G. (Cady) Coleman, mission specialist. In the background is a large poster depicting the Chandra X-Ray Observatory.

Galactic Views (132)


Galactic Pyrotechnics on Display

NASA – A galaxy about 23 million light years away is the site of impressive, ongoing fireworks. Rather than paper, powder and fire, this galactic light show involves a giant black hole, shock waves and vast reservoirs of gas.

This galactic fireworks display is taking place in NGC 4258, also known as M106, a spiral galaxy like the Milky Way. This galaxy is famous, however, for something that our galaxy doesn’t have – two extra spiral arms that glow in X-ray, optical and radio light. These features, or anomalous arms, are not aligned with the plane of the galaxy, but instead intersect with it.

The anomalous arms are seen in this new composite image of NGC 4258, where X-rays from NASA’s Chandra X-ray Observatory are blue, radio data from the NSF’s Karl Jansky Very Large Array are purple, optical data from NASA’s Hubble Space Telescope are yellow and infrared data from NASA’s Spitzer Space Telescope are red.

A new study made with Spitzer shows that shock waves, similar to sonic booms from supersonic planes, are heating large amounts of gas – equivalent to about 10 million suns. What is generating these shock waves? Researchers think that the supermassive black hole at the center of NGC 4258 is producing powerful jets of high-energy particles. These jets strike the disk of the galaxy and generate shock waves. These shock waves, in turn, heat the gas – composed mainly of hydrogen molecules – to thousands of degrees.

The Chandra X-ray image reveals huge bubbles of hot gas above and below the plane of the galaxy. These bubbles indicate that much of the gas that was originally in the disk of the galaxy has been heated and ejected into the outer regions by the jets from the black hole.

The ejection of gas from the disk by the jets has important implications for the fate of this galaxy. Researchers estimate that all of the remaining gas will be ejected within the next 300 million years – very soon on cosmic time scales – unless it is somehow replenished. Because most of the gas in the disk has already been ejected, less gas is available for new stars to form. Indeed, the researchers used Spitzer data to estimate that stars are forming in the central regions of NGC 4258, at a rate which is about ten times less than in the Milky Way galaxy.

The European Space Agency’s Herschel Space Observatory was used to confirm the estimate from Spitzer data of the low star formation rate in the central regions of NGC 4258. Herschel was also used to make an independent estimate of how much gas remains in the center of the galaxy. After allowing for the large boost in infrared emission caused by the shocks, the researchers found that the gas mass is ten times smaller than had been previously estimated.

Because NGC 4258 is relatively close to Earth, astronomers can study how this black hole is affecting its galaxy in great detail. The supermassive black hole at the center of NGC 4258 is about ten times larger than the one in the Milky Way and is consuming material at a faster rate, potentially increasing its impact on the evolution of its host galaxy.

These results were published in the June 20, 2014 issue of The Astrophysical Journal Letters and are available online. The authors are Patrick Ogle, Lauranne Lanz and Philip Appleton from the California Institute of Technology in Pasadena, California.

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

Image Credit: X-ray: NASA/CXC/Caltech/P.Ogle et al; Optical: NASA/STScI; IR: NASA/JPL-Caltech; Radio: NSF/NRAO/VLA

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Galactic Views (126)


Inside the Flame Nebula

NASA – Stars are often born in clusters, in giant clouds of gas and dust. Astronomers have studied two star clusters using NASA’s Chandra X-ray Observatory and infrared telescopes and the results show that the simplest ideas for the birth of these clusters cannot work, as described in our latest press release.

This composite image shows one of the clusters, NGC 2024, which is found in the center of the so-called Flame Nebula about 1,400 light years from Earth. In this image, X-rays from Chandra are seen as purple, while infrared data from NASA’s Spitzer Space Telescope are colored red, green, and blue.

A study of NGC 2024 and the Orion Nebula Cluster, another region where many stars are forming, suggest that the stars on the outskirts of these clusters are older than those in the central regions. This is different from what the simplest idea of star formation predicts, where stars are born first in the center of a collapsing cloud of gas and dust when the density is large enough.

The research team developed a two-step process to make this discovery. First, they used Chandra data on the brightness of the stars in X-rays to determine their masses. Next, they found out how bright these stars were in infrared light using data from Spitzer, the 2MASS telescope, and the United Kingdom Infrared Telescope. By combining this information with theoretical models, the ages of the stars throughout the two clusters could be estimated.

According to the new results, the stars at the center of NGC 2024 were about 200,000 years old while those on the outskirts were about 1.5 million years in age. In Orion, the age spread went from 1.2 million years in the middle of the cluster to nearly 2 million years for the stars toward the edges.

Explanations for the new findings can be grouped into three broad categories. The first is that star formation is continuing to occur in the inner regions. This could have happened because the gas in the outer regions of a star-forming cloud is thinner and more diffuse than in the inner regions. Over time, if the density falls below a threshold value where it can no longer collapse to form stars, star formation will cease in the outer regions, whereas stars will continue to form in the inner regions, leading to a concentration of younger stars there.

Another suggestion is that old stars have had more time to drift away from the center of the cluster, or be kicked outward by interactions with other stars. Finally, the observations could be explained if young stars are formed in massive filaments of gas that fall toward the center of the cluster.

The combination of X-rays from Chandra and infrared data is very powerful for studying populations of young stars in this way. With telescopes that detect visible light, many stars are obscured by dust and gas in these star-forming regions, as shown in this optical image of the region.

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 in Cambridge, Mass., controls Chandra’s science and flight operations.

Image credit: X-ray: NASA/CXC/PSU/K.Getman, E.Feigelson, M.Kuhn & the MYStIX team; Infrared:NASA/JPL-Caltech

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Galactic Views (120)


Chandra Observatory Sees a Heart in the Darkness

NASA – This Chandra X-Ray Observatory image of the young star cluster NGC 346 highlights a heart-shaped cloud of 8 million-degree Celsius gas in the central region. Evidence from radio, optical and ultraviolet telescopes suggests that the hot cloud, which is about 100 light years across, is the remnant of a supernova explosion that occurred thousands of years ago.

The progenitor could have been a companion of the massive young star that is responsible for the bright X-ray source at the top center of the image. This young star, HD 5980, one of the most massive known, has been observed to undergo dramatic eruptions during the last decade. An alternative model for the origin of the hot cloud is that eruptions of HD 5980 long ago produced the cloud of hot gas, in a manner similar to the gas cloud observed around the massive star Eta Carinae. Future observations will be needed to decide between the alternatives. Until then, the nature of the heart in the darkness will remain mysterious.

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Image Credit: NASA/CXC/U.Liege/Y.Nazé et al.

Galactic Views (113)


X-ray Binary Circinus X-1

NASA – The youngest member of an important class of objects has been found using data from NASA’s Chandra X-ray Observatory and the Australia Compact Telescope Array. A composite image shows the X-rays in blue and radio emission in purple, which have been overlaid on an optical field of view from the Digitized Sky Survey. This discovery, described in the press release, allows scientists to study a critical phase after a supernova and the birth of a neutron star.

Systems known as “X-ray binaries” are some of the brightest X-ray sources in the sky. They consist of either an ultra-dense star packed with neutrons — a.k.a., a “neutron star” — or a black hole that is paired with a normal star like the sun. As these two objects orbit one another, the neutron star or black hole pulls material from the companion star onto it.

A new study shows that the X-ray binary called Circinus X-1 is less than 4,600 years old, making it the youngest ever seen. Astronomers have detected hundreds of X-ray binaries throughout the Milky Way and other nearby galaxies. However, these older X-ray binaries only reveal information about what happens later in the evolution of these systems.

Astronomers were able to determine the age of Circinus X-1 by examining material around the orbiting pair. While the source itself has been known for decades, the neutron star is usually so bright that the glare from its X-ray light overwhelms any faint emission surrounding it. The new Chandra data were obtained while the neutron star was in a very faint state, which meant it was dim enough for astronomers to detect the faint afterglow created by the supernova explosion plowing through the surrounding interstellar gas. This, combined with characteristics of the radio emission, allowed the researchers to pinpoint the age of the supernova remnant. In turn, this information reveals the age of the neutron star since they were formed at the same time.

These results have been published in the December 4th issue of The Astrophysical Journal. In addition to those mentioned above, the other authors on this paper are Peter Jonker of the SRON Netherlands Institute for Space Research, Niel Brandt of Penn State University, Daniel Emilio Calvelo-Santos of the University of Southampton, Tasso Tzioumis of the Australia Telescope National Facility, Michael Nowak and Norbert Schultz of the Kavli Institute/MIT, Rudy Wijnands and Michiel van der Klis of the University of Amsterdam.

Image credit: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S. Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA