Dwarf galaxies in the NGC 5846 group
- Author(s)
- Paul Eigenthaler, Werner Zeilinger
- Abstract
Dwarf galaxies are known to be the most numerous type of galaxies in the nearby universe and dominate the faint end of the cluster luminosity function. A significant population of dwarf galaxies is predicted from galaxy formation. In particular dwarf elliptical galaxies can be considered as good indicators for denser regions in the universe like groups and clusters of galaxies. Recent observations of nearby galaxy groups (M81, Sculptor, NGC 5128) have given insight on the very faint end of the galaxy luminosity function. Being good tracers for the group potential and merging effects, dwarf galaxies are also ideal laboratories for galaxy evolution and galaxy dynamics in nearby groups. For the present study we investigate the dwarf population of the loose galaxy group around NGC 5846 which is known for its diffuse X-ray emission (Mulchaey 2003). The Sloan Digital Sky Survey has been searched for all galaxies with redshifts less than cz = 3000 km s-1 in a 2° circle around NGC 5846. This search yielded a sample of 56 dwarf galaxies including 13 dwarfs discovered earlier by Zabludoff et al. so that the total number of spectroscopic group members including bright galaxies now counts 75 objects. A colour magnitude diagram has been constructed to analyze the stellar populations within the group. Surface brightness profiles, ellipticity and position angle of the new found dwarf ellipticals were measured in the Sloan g r i bands using the IRAF ellipse task. To quantify the profile shape, a SeŽrsic model was fitted to each galaxy showing nearly exponential profiles for all objects. 43% of the dwarfs show emission lines in their spectra which give insight on the SFR and nuclear activity of these objects. Furthermore the radial velocities of all group members were used to calculate the velocity dispersion of the group which yielded a value of 324 km s -1. Œ 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
- Organisation(s)
- Department of Astrophysics
- Journal
- Astronomische Nachrichten
- Volume
- 326
- Pages
- 490-491
- No. of pages
- 2
- ISSN
- 0004-6337
- Publication date
- 2005
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/07442ce6-4b45-4ab1-b595-1c2e251256c1