Galaxies contain hundreds of billions of stars. They often group together in clusters, with a history of sharing and tearing their gases and dark matter. This is the Triangulum Galaxy, also known as M33. It is in the Local Group of galaxies, which includes the Andromeda Galaxy and our galaxy, the Milky Way. M33 is over thirty thousand light years across, and more than two million light years away. The optical data show the many stars within the galaxy as well as reddish star forming regions that are filled with hot Hydrogen gas. The radio data from the Very Large Array (VLA) represented in blue, reveal the cool Hydrogen gas within the galaxy, gas which cannot be seen with an optical telescope. Combined together, the radio and optical give a more comprehensive view of star formation in this galaxy.
Credit: B. Saxton, NRAO/AUI/NSF using data provided by T. Rector, NOAO/AURA/NSF
Technical Details Telescope: UK Schmidt; UK Schmidt; UK Schmidt; VLA; VLA Band: B; R; V; L; L Date: Wed Apr 25 16:35:43 EDT 2012; Wed Apr 25 16:35:52 EDT 2012; Wed Apr 25 16:35:33 EDT 2012; 1998-06-11T16:56:02.1; 1998-05-11T01:05:51.6 Center: RA: 1:33:50.9, Dec: 30:39:35.79 Field of View: 120.1 x 75.75 arcminutes