Confirmation of Faint Dwarf Galaxies in the M81 Group
Abstract
We have followed up on the results of a 65 deg2 CFHT/MegaCam imaging survey of the nearby M81 Group searching for faint and ultra-faint dwarf galaxies. The original survey turned up 22 faint candidate dwarf members. Based on two-color HST ACS/WFC and WFPC2 photometry, we now confirm 14 of these as dwarf galaxy members of the group. Distances and stellar population characteristics are discussed for each. To a completeness limit of M_{r^{\prime }} = -10, we find a galaxy luminosity function slope of -1.27 ± 0.04 for the M81 Group. In this region, there are now 36 M81 Group members known, including 4 blue compact dwarfs; 8 other late types including the interacting giants M81, NGC 3077, and M82; 19 early type dwarfs; and at least 5 potential tidal dwarf galaxies. We find that the dSph galaxies in M81 appear to lie in a flattened distribution, similar to that found for the Milky Way and M31. One of the newly discovered dSph galaxies has properties similar to the ultra-faint dwarfs being found in the Local Group with a size Re ~ 100 pc and total magnitude estimates M_{r^{\prime }} = -6.8 and MI ~ -9.1.
- Publication:
-
The Astronomical Journal
- Pub Date:
- November 2013
- DOI:
- 10.1088/0004-6256/146/5/126
- arXiv:
- arXiv:1309.4130
- Bibcode:
- 2013AJ....146..126C
- Keywords:
-
- galaxies: dwarf;
- galaxies: fundamental parameters;
- galaxies: groups: individual: M81;
- galaxies: luminosity function;
- mass function;
- galaxies: photometry;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 56 pages including 39 figures. To be published in AJ