Enormous HI disks around nearby radio galaxies
2008; American Institute of Physics; Linguagem: Inglês
10.1063/1.2973566
ISSN1935-0465
AutoresBjorn Emonts, R. Morganti, Tom Oosterloo, C. N. Tadhunter, Robert Minchin, Emmanuel Momjian,
Tópico(s)Galaxies: Formation, Evolution, Phenomena
ResumoWe present the detection of enormous disks/rings of neutral hydrogen (HI) gas around several nearby radio‐loud early‐type galaxies. Goal of our study was to use HI observations to look for evidence of galaxy mergers or interactions (tails, bridges, disks, etc.) that could be related to the triggering of the radio source in a complete sample of nearby radio galaxies. One case, B2 0648+27, was studied in great detail to be a product of a major merger—it is a direct link between (Ultra‐) Luminous Infra‐Red Galaxies and Radio Galaxies, for which we trace the different stages of merger, starburst and AGN activity. We detect other large‐scale HI disks and rings only around the host galaxies of several low‐power compact radio sources as well as the powerful FR‐II radio galaxy NGC 612; the hosts of extended FR‐I radio sources seem to be devoid of large‐scale HI. This suggest a fundamental difference in the host galaxy properties—and perhaps also the triggering mechanism—of different types of radio sources.
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