Surface Photometry of Virgo Dwarf Ellipticals
Abstract
Deep surface photometry has been carried out for 13 dE's and dE,N's in the Virgo cluster using images from the CFHT. A modified exponential function is found to fit most profiles quite well. The known relation between galaxy luminosity and the shape parameter n is confirmed, although with considerable scatter. Most of the galaxies are well fit by purely elliptical isophotes, although 3 galaxies show disky isophotes (at the ~ 1% level) and one is boxy. The luminosities of the (unresolved, with half-mass radii of less than 30-40pc) nuclei in the 8 dE,N galaxies have M_V < -10, thus are more luminous than typical globular clusters. They are likely giant star clusters that formed from a left-over reservoir of gas in the core regions, although this may not be only mechanism from which dE nuclei form. The faintest objects in the sample have not been observed before, and evidence is presented that they are likely faint dSph's in the Virgo cluster.
- Publication:
-
The Astronomical Journal
- Pub Date:
- February 1997
- DOI:
- 10.1086/118273
- Bibcode:
- 1997AJ....113..531D