Determinación estadística de propiedades de la sub estructura de materia: Número de satélites

LARES, MARCELO; GARCIA LAMBAS, DIEGO RODOLFO

San Juan

Congreso; 51 Reunión Anual de la Asociación Argentina de Astronomía; 2008

AAA - OAFA

In this work, we determine the mean number of galaxies in the range -18<M_r<-14. around bright galaxies, both isolated and in galaxy systems. We explore systems in a wide range in mass, and in the redshift range 0.03<z<0.1. We combine the position information obtained in the spectroscopic Sloan survey (DR7) with the photometric information to identify overdensity regions asociated with satellite galaxies. We first explore the number density profile to obtain the ideal extent of the overdensity, and then we determine the fraction of faint galaxies in the excess sample. We find that the number of satellites around bright, isolated galaxies ranges from 2.6+/-0.4 for the brightest and reddest to nearly one for hosts with M_r~-20.5. The more massive groups of galaxies have greater number of faint galaxies, ranging from ~50 per system on poor groups up to ~200 on X-ray emitting clusters.