Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-01-25
Astronomy and Astrophysics
Astrophysics
Accepted for publication in A&A, 13 pages, 6 figures. A version with full resolution figures is available at http://www.astr
Scientific paper
10.1051/0004-6361:20066384
We discuss the morphology and kinematics of the HI of a sample of 30 southern gas-rich early-type galaxies selected from the HI Parkes All-Sky Survey (HIPASS). This is the largest collection of high-resolution HI data of a homogeneously selected sample. Given the sensitivity of HIPASS, these galaxies represent the most HI-rich early-type galaxies. In two-thirds of the galaxies, we find the HI to be in a large, regular disk- or ring-like structure that in some cases is strongly warped. In the remaining cases we find the HI distributed in irregular tails or clouds offset from the galaxy. The giant, regular HI structures can be up to ~200 kpc in diameter and contain up to 10^10 M_sun of HI. The incidence of irregular HI structures appears to be somewhat higher in elliptical galaxies, but the large, regular structures are observed in both elliptical and S0 galaxies and are not strictly connected to the presence of a stellar disk. If these two types of galaxies are the result of different formation paths, this is not strongly reflected in the characteristics of the HI. The size and the regular kinematics of the HI structures imply that the neutral hydrogen must have settled in these galaxies several Gyr ago. Merging as well as gas accretion from the IGM are viable explanations for the origin of the gas in these galaxies. The average column density of the HI is low so that little star formation is expected to occur and these early-type galaxies can remain gas rich for very long periods of time. The large HI structures likely represent key structures for tracing the origin and evolution of these galaxies.
Morganti Rafaella
Oosterloo Tom
Sadler Elaine M.
Serra Paolo
van der Hulst J. M.
No associations
LandOfFree
Extended, regular HI structures around early-type galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Extended, regular HI structures around early-type galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Extended, regular HI structures around early-type galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-328303