Volume 390, Number 3, August II 2002
|Page(s)||829 - 861|
|Section||Cosmology (including clusters of galaxies)|
|Published online||14 August 2002|
The Westerbork HI survey of spiral and irregular galaxies
I. HI imaging of late-type dwarf galaxies
Kapteyn Astronomical Institute, PO Box 800, 9700 AV Groningen, The Netherlands
2 Dept. of Physics and Astronomy Johns Hopkins University, 3400 N. Charles Str., Baltimore, MD 21218, USA
3 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
4 Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
Accepted: 6 December 2001
Neutral hydrogen observations with the Westerbork Synthesis Radio Telescope are presented for a sample of 73 late-type dwarf galaxies. These observations are part of the WHISP project (Westerbork Survey of Spiral and Irregular Galaxies). Here we present maps, velocity fields, global profiles and radial surface density profiles of , as well as masses, radii and line widths. For the late-type galaxies in our sample, we find that the ratio of extent to optical diameter, defined as 6.4 disk scale lengths, is on average 1.8 ± 0.8, similar to that seen in spiral galaxies. Most of the dwarf galaxies in this sample are rich in with a typical of 1.5. The relative content increases towards fainter absolute magnitudes and towards fainter surface brightnesses. Dwarf galaxies with lower average column densities also have lower average optical surface brightnesses. We find that lopsidedness is as common among dwarf galaxies as it is in spiral galaxies. About half of the dwarf galaxies in our sample have asymmetric global profiles, a third has a lopsided distribution, and about half shows signs of kinematic lopsidedness.
Key words: surveys / galaxies: dwarf / galaxies: structure
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.