2007/01/16 by Bjorn Emonts, R. Morganti, Emonts, B. H. C. +9
Physics and Astronomy · #Galaxies: Formation, Evolution, Phenomena #Astrophysics and Star Formation Studies #Astronomy and Astrophysical Research
paper · pdf · doi:10.48550/arxiv.astro-ph/0701438
We present results of a study of neutral hydrogen (HI) in a complete sample of nearby non-cluster radio galaxies. We find that radio galaxies with large amounts of extended HI (MHI >= 109 Msolar) all have a compact radio source. The host galaxies of the more extended radio sources, all of Fanaroff & Riley type-I, do not contain these amounts of HI. We discuss several possible explanations for this segregation. The large-scale HI is mainly distributed in disk- and ring-like structures with sizes up to 190 kpc and masses up to 2 x 1010 Msolar. The formation of these structures could be related to past merger events, although in some cases it may also be consistent with a cold-accretion scenario.