Issue |
A&A
Volume 566, June 2014
|
|
---|---|---|
Article Number | A71 | |
Number of page(s) | 32 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/201322657 | |
Published online | 17 June 2014 |
Dynamics of starbursting dwarf galaxies⋆,⋆⋆
III. A H I study of 18 nearby objects
1
Kapteyn Astronomical Institute, University of Groningen,
Postbus 800,
9700 AV
Groningen,
The Netherlands
e-mail:
lelli@astro.rug.nl
2
Department of Astronomy, Case Western Reserve
University, 10090 Euclid
Avenue, Cleveland,
OH
44106,
USA
e-mail:
federico.lelli@case.edu
3
Department of Physics and Astronomy, University of
Bologna, viale Berti Pichat
6/2, 40127
Bologna,
Italy
Received:
12
September
2013
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 (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A71
© ESO, 2014
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