Volume 566, June 2014
|Number of page(s)||32|
|Published online||17 June 2014|
III. A H I study of 18 nearby objects
Kapteyn Astronomical Institute, University of Groningen,
2 Department of Astronomy, Case Western Reserve University, 10090 Euclid Avenue, Cleveland, OH 44106, USA
3 Department of Physics and Astronomy, University of Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
Accepted: 24 April 2014
We investigate the dynamics of starbursting dwarf galaxies, using both new and archival H I observations. We consider 18 nearby galaxies that have been resolved into single stars by HST observations, providing their star formation history and total stellar mass. We find that 9 objects have a regularly rotating H I disk, 7 have a kinematically disturbed H I disk, and 2 show unsettled H I distributions. Two galaxies (NGC 5253 and UGC 6456) show a velocity gradient along the minor axis of the H I disk, which we interpret as strong radial motions. For galaxies with a regularly rotating disk we derive rotation curves, while for galaxies with a kinematically disturbed disk, we estimate the rotation velocities in their outer parts. We derive baryonic fractions within about 3 optical scale lengths and find that, on average, baryons constitute at least 30% of the total mass. Despite the star formation having injected ~1056 ergs in the ISM in the past ~500 Myr, these starbursting dwarfs have both baryonic and gas fractions similar to those of typical dwarf irregulars, suggesting that they did not eject a large amount of gas out of their potential wells.
Key words: galaxies: dwarf / galaxies: starburst / galaxies: kinematics and dynamics / galaxies: evolution / dark matter
Appendices are available in electronic form at http://www.aanda.org
H I datacubes (FITS files) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A71
© ESO, 2014
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