Chandra Observes Galaxy Groups

386510 01: A new Chandra image shows remarkable detail and complexity in the central region of the compact galaxy group known as HGC 62, March 7, 2001. Such galaxy groups, which contain fewer galaxies than the better-known galaxy clusters, are an important class of objects because they may serve as cosmic building blocks in the large-scale structure of the Universe. After galaxies themselves form in the early Universe, such groups of galaxies may be the next systems to evolve. Later, it is believed, these groups of galaxies may combine with each other to form the bigger galaxy clusters. Most galaxies in the present-day Universe are still in groups or poor clusters. Our own Milky Way Galaxy, along with about two dozen other galaxies, including the Andromeda Nebula (M31) and the Large and Small Magellanic Clouds, is part of a galaxy group known as the Local Group. A team of scientists, led by Jan Vrtilek (Harvard-Smithsonian Center for Astrophysics), observed HGC 62 with Chandra for about 50,000 seconds with the Advanced CCD Imaging Spectrometer. The range of X-ray surface brightness is represented in this image by various colors: green depicts the lower-brightness regions while purple and reddish indicate increasing X-ray intensity. (Photo by Newsmakers)