| Description: | Stars form from contracting gas clouds. However, if galaxies get smaller and smaller, these galaxies may not be heavy enough to skweeze the gas clouds together so that stars will form. So it is conceivable that there is a lower limit to the size of a galaxy because in smaller galaxies no stars can form. Moreover, small galaxies should be gas rich because not much gas has been converted into stars. Using the WSRT, we have searched (promotieonderzoek Katarina Kovac) for these small galaxies by surveying a region of about 100 square degrees in the constellation Canes Venatici ("the Hunting Dogs"). Several very small, very gas-rich galaxies have been discovered, a few are shown in the figure. The size of each panel is about 15,000 x 15,000 lightyears; the smallest galaxy is about 1,000 lightyears in size (for comparison: the Milky Way, our own Galaxy, is more than 100,000 lightyears in size!!). Although several small galaxies have been found, the number found is smaller than would be expected based on the number of large galaxies in the region. See also: http://arxiv.org/abs/astro-ph/0508072 |
