paper

"Dark galaxies" and local very metal-poor gas-rich galaxies: possible interrelations

arXiv:0708.2031 · doi:10.1017/S1743921307014196

Abstract

There are only a few ``dark galaxy'' candidates discovered to date in the local Universe. One of the most prominent of them is the SW component of a merging system HI 1225+01. On the other hand, the number of known very metal-poor gas-rich dwarfs similar to IZw18 and SBS 0335-052 E,W has grown drastically during the last decade, from a dozen and a half to about five dozen. Many of them are very gas-rich, having from ~90 to 99% of all baryons in gas. For some of such objects that have the deep photometry data, no evidences for the light of old stars are found. At least a half of such galaxies with the prominent starbursts have various evidences of interactions, including advanced mergers. This suggests that a fraction of this group objects can be a kind of very stable protogalaxies (or ``dark galaxies''), which have recently experienced strong disturbances from nearby massive galaxy-size bodies. Such a collision caused the gas instabilities and its collapse with the subsequent onset of starburst. We briefly discuss the morphology and gas kinematics for the subsample of the most metal-poor dwarfs that illustrate this picture. We discuss also the relation of these rare galaxies to the processes by which ``dark galaxies'' can occasionally transform to optically visible galaxies.

arXiv comment5 pages, no figures, to be published in Proc. of IAUS 244 "Dark Galaxies and Lost Baryons". Improved English, references updated

References in corpus (17)

Cited by in corpus (1)