Neutral hydrogen clouds near early-type dwarf galaxies of the Local Group
Date
2006
Authors
Bouchard, Antoine
Carignan, C
Staveley-Smith, Lister
Journal Title
Journal ISSN
Volume Title
Publisher
University of Chicago Press
Abstract
Parkes neutral hydrogen 21 cm line (H I) observations of the surroundings of nine early-type Local Group dwarfs are presented. We detected numerous H I clouds in the general direction of those dwarfs, and these clouds are often offset from the optical center of the galaxies. Although all the observed dwarfs, except Antlia, occupy phase-space regions where the high-velocity cloud (HVC) density is well above average, the measured offsets are smaller than one would expect from a fully random cloud distribution. Possible association is detected for 11 of the 16 investigated clouds, while for two galaxies, Sextans and Leo I, no H I was detected. The galaxies in which H i clouds were found not to coincide with the optical yet have a significant probability of being associated are the Sculptor dwarf, Tucana, LGS 3, Cetus, and Fomax. If the clouds are indeed associated, these galaxies have H I masses of MH I, = 2 × 105, 2 × 106, 7 × 105, 7 × 105, and 1 × 105 M⊙, respectively. However, neither ram pressure nor tidal stripping can easily explain the offsets. In some cases, large offsets are found where ram pressure should be the least effective.
Description
Keywords
Keywords: Galaxies: dwarf; Galaxies: ISM; ISM: clouds; Local Group; Radio lines: galaxies; Radio lines: ISM
Citation
Collections
Source
Astronomical Journal
Type
Journal article
Book Title
Entity type
Access Statement
License Rights
DOI
Restricted until
2037-12-31