Detalles de publicación
PP 014043
Satellite galaxies around present-day massive ellipticals
(1) Departamento de Astrofisica, Universidad de La Laguna, E-38205, La
Laguna, Tenerife, Spain
(2) IAC
(3) Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ
Using the spectroscopic NYU-VAGC and the photometric PHOTOZ catalogues of the Sloan Digital Sky Survey (SDSS DR7), we have explored the satellite distribution around ~1000 massive (M*>2x10^{11}Msun) visually classified elliptical galaxies down to a satellite mass ratio of 1:400 (i.e. 5x10^{8}<M$_{sat}<2x10^{11}Msun). Our host galaxies were selected to be representative of a mass complete sample. The satellites of these galaxies were searched within a projected radial distance of 100 kpc to their hosts. We have found that only 20-23% of the massive ellipticals has at least a satellite down to a mass ratio 1:10. This number increases to 45-52% if we explore satellites down to 1:100 and is >60-70% if we go further down to 1:400. The average projected radial distance of the satellites to their hosts for our whole sample down to 1:400 is ~59 kpc (which can be decreased at least down to 50 kpc if we account for incompleteness effects). The number of satellites per galaxy host only increases very mildly at decreasing the satellite mass. The fraction of mass which is contained in the satellites down to a mass ratio of 1:400 is 8% of the total mass contained by the hosts. Satellites with a mass ratio from 1:2 to 1:5 (with ~28% of the total mass of the satellites) are the main contributor to the total satellite mass. If the satellites eventually infall into the host galaxies, the merger channel will be largely dominated by satellites with a mass ratio down to 1:10 (as these objects have 68% of the total mass in satellites).