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01.14.11
A new Chandra X-ray Observatory image of Messier 82, or M82, shows the result of star formation on overdrive. M82 is located about 12 million light years from Earth and is the nearest place to us where the conditions are similar to those when the Universe was much younger with lots of stars forming.
M82 is a so-called starburst galaxy, where stars are forming at rates that are tens or even hundreds of times higher than in a normal galaxy. The burst of star birth may be caused by a close encounter or collision with another galaxy, which sends shock waves rushing through the galaxy. In the case of M82, astronomers think that a brush with its neighbor galaxy M81 millions of years ago set off this torrent of star formation.
M82 is seen nearly edge-on with its disk crossing from about 10 o’clock to about 4 o’clock in this image from Chandra (where low, medium, and high-energy X-rays are colored red, green, and blue respectively.) Among the 104 point-like X-ray sources in the image, eight so far have been observed to be very bright in X-rays and undergo clear changes in brightness over periods of weeks and years. This means they are excellent candidates to be black holes pulling material from companion stars that are much more massive than the Sun. Only a handful of such binary systems are known in the Local Group of galaxies containing the Milky Way and M31.
Chandra observations are also important in understanding the rapid rate at which supernovas explode in starburst galaxies like M82. When the shock waves travel through the galaxy, they push on giant clouds of gas and dust, which causes them to collapse and form massive stars. These stars, in turn, use up their fuel quickly and explode as supernovas. These supernovas produce expanding bubbles of multimillion-degree gas that extend for millions light years away from the galaxy’s disk. These bubbles are seen as the large red areas to the upper right and lower left of the image.
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.
Read more/access larger images: http://chandra.harvard.edu/photo/2011/m82/
Image, Text, Credits: NASA / CXC / Wesleyan Univ. / R. Kilgard et al.
Henize 2-10, a Dwarf Starburst Galaxy
The combined observations from multiple telescopes of Henize 2-10, a dwarf starburst galaxy located about 30 million light years from Earth, has provided astronomers with a detailed new look at how galaxy and black hole formation may have occured in the early Universe. This image shows optical data from the Hubble Space Telescope in red, green and blue, X-ray data from NASA's Chandra X-ray Observatory in purple, and radio data from the National Radio Astronomy Observatory's Very Large Array in yellow. A compact X-ray source at the center of the galaxy coincides with a radio source, giving evidence for an actively growing supermassive black hole with a mass of about one million times that of the sun.
Stars are forming in Henize 2-10 at a prodigious rate, giving the star clusters in this galaxy their blue appearance. This combination of a burst of star formation and a massive black hole is analogous to conditions in the early Universe. Since Henize 2-10 does not contain a significant bulge of stars in its center, these results show that supermassive black hole growth may precede the growth of bulges in galaxies. This differs from the relatively nearby Universe where the growth of galaxy bulges and supermassive black holes appears to occur in parallel.
A paper describing these results was published online in Nature on January 9th, 2011 by Amy Reines and Gregory Sivakoff of the University of Virginia, Kelsey Johnson of the University of Virginia and the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia and Crystal Brogan also of NRAO in Virgina.
Image, Tex, Credits: X-ray (NASA / CXC / Virginia / A.Reines et al); Radio (NRAO / AUI / NSF); Optical (NASA / STScI).
Read more/access larger images: http://chandra.harvard.edu/photo/2011/he210/
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