Tag Archives: Chandra X-ray Observatory

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

Galactic Views (110)


Exploring the Third Dimension of Cassiopeia A

NASA – One of the most famous objects in the sky – the Cassiopeia A supernova remnant – will be on display like never before, thanks to NASA’s Chandra X-ray Observatory and a new project from the Smithsonian Institution. A new three-dimensional (3D) viewer, being unveiled this week, will allow users to interact with many one-of-a-kind objects from the Smithsonian as part of a large-scale effort to digitize many of the Institutions objects and artifacts.

Scientists have combined data from Chandra, NASA’s Spitzer Space Telescope, and ground-based facilities to construct a unique 3D model of the 300-year old remains of a stellar explosion that blew a massive star apart, sending the stellar debris rushing into space at millions of miles per hour. The collaboration with this new Smithsonian 3D project will allow the astronomical data collected on Cassiopeia A, or Cas A for short, to be featured and highlighted in an open-access program — a major innovation in digital technologies with public, education, and research-based impacts.

To coincide with Cas A being featured in this new 3D effort, a specially-processed version of Chandra’s data of this supernova remnant is also being released. This new image shows with better clarity the appearance of Cas A in different energy bands, which will aid astronomers in their efforts to reconstruct details of the supernova process such as the size of the star, its chemical makeup, and the explosion mechanism. The color scheme used in this image is the following: low-energy X-rays are red, medium-energy ones are green, and the highest-energy X-rays detected by Chandra are colored blue.

Cas A is the only astronomical object to be featured in the new Smithsonian 3D project. This and other objects in the collection – including the Wright brothers plane, a 1,600-year-old stone Buddha, a gunboat from the Revolutionary War, and fossil whales from Chile — were being showcased in the Smithsonian X 3D event, taking place on November 13th and 14th at the Smithsonian in Washington, DC. In addition to new state-of-the-art 3D viewer, the public will be able to explore these objects through original videos, online tours, and other supporting materials.

Cas A is the only supernova remnant to date to be modeled in 3D. In order to create this visualization, unique software that links the fields of astrophysics and medical imaging (known as “astronomical medicine”) was used. Since its initial release in 2009, the 3D model has proven a rich resource for scientists as well as an effective tool for communicating science to the public. Providing this newly formatted data in an open source framework with finely-tuned contextual materials will greatly broaden awareness and participation for general public, teacher, student and researcher audiences.

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. Image credit: NASA/CXC/SAO

Galactic Views (104)


Collage: Eight New Images of the X-ray Universe

NASA – To celebrate American Archive Month 2013 this October, NASA’s Chandra X-ray Observatory released eight never-before-seen images from its archive. The Chandra Data Archive plays a central role in the Chandra mission by enabling the astronomical community – as well as the greater public – access to data collected by the observatory.

Image credit: NASA/CXC/SAO)

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Galactic Views (98)


Dwarf Galaxy Caught Ramming Into a Large Spiral Galaxy

NASA – Observations with NASA’s Chandra X-ray Observatory have revealed a massive cloud of multimillion-degree gas in a galaxy about 60 million light years from Earth. The hot gas cloud is likely caused by a collision between a dwarf galaxy and a much larger galaxy called NGC 1232. If confirmed, this discovery would mark the first time such a collision has been detected only in X-rays, and could have implications for understanding how galaxies grow through similar collisions.

An image combining X-rays and optical light shows the scene of this collision. The impact between the dwarf galaxy and the spiral galaxy caused a shock wave − akin to a sonic boom on Earth – that generated hot gas with a temperature of about six million degrees. Chandra X-ray data, in purple, show the hot gas has a comet-like appearance, caused by the motion of the dwarf galaxy. Optical data from the European Southern Observatory’s Very Large Telescope reveal the spiral galaxy in blue and white. X-ray point sources have been removed from this image to emphasize the diffuse emission.

Near the head of the comet-shaped X-ray emission (mouse over the image for the location) is a region containing several very optically bright stars and enhanced X-ray emission. Star formation may have been triggered by the shock wave, producing bright, massive stars. In that case X-ray emission would be generated by massive star winds and by the remains of supernova explosions as massive stars evolve.

The mass of the entire gas cloud is uncertain because it cannot be determined from the two-dimensional image whether the hot gas is concentrated in a thin pancake or distributed over a large, spherical region. If the gas is a pancake, the mass is equivalent to forty thousand Suns. If it is spread out uniformly, the mass could be much larger, about three million times as massive as the Sun. This range agrees with values for dwarf galaxies in the Local Group containing the Milky Way.

The hot gas should continue to glow in X-rays for tens to hundreds of millions of years, depending on the geometry of the collision. The collision itself should last for about 50 million years. Therefore, searching for large regions of hot gas in galaxies might be a way to estimate the frequency of collisions with dwarf galaxies and to understand how important such events are to galaxy growth.

An alternative explanation of the X-ray emission is that the hot gas cloud could have been produced by supernovas and hot winds from large numbers of massive stars, all located on one side of the galaxy. The lack of evidence of expected radio, infrared, or optical features argues against this possibility.

A paper by Gordon Garmire of the Huntingdon Institute for X-ray Astronomy in Huntingdon, PA describing these results is available online and was published in the June 10th, 2013 issue of The Astrophysical Journal.

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.

Image credit: X-ray: NASA/CXC/Huntingdon Institute for X-ray Astronomy/G. Garmire; Optical: ESO/VLT