Detalles de publicación
PP 014071
Deep spectroscopic luminosity function of Abell 85: no evidence for a steep upturn of the faint-end slope
(1) Instituto de Astrofisica de Canarias, C/ Via Lactea s/n, 38200 La Laguna, Tenerife, Spain,
(2) Departamento de Astrofisica, Universidad de La Laguna, E-38205 La Laguna, Tenerife, Spain,
(3) NRC Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, V9E2E7, Canada
(4) Dipartimento di Fisica, Universit\`a di Torino, Via P. Giuria 1, I-10125, Torino, Italy\\
(5) Istituto Nazionale di Fisica Nucleare (INFN), sezione di Torino, Via P. Giuria 1, I-10125, Torino, Italy\\
(6) Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Torino, Strada Osservatorio 20, I-10025 Pino Torinese, Torino, Italy\\
(7) School of Physics \& Astronomy, University of St Andrews, St Andrews KY16 9AJ, Fife, Scotland, UK}
We present a new deep determination of the spectroscopic LF within the virial radius of the nearby and massive Abell\,85 (A85) cluster down to the dwarf regime (M* + 6) using VLT/VIMOS spectra for $\sim 2000$ galaxies with m$_r \leq 21$ mag and $\langle \mu_{e,r} \rangle \leq 24$ mag arcsec$^{-2}$. The resulting LF from 438 cluster members is best modelled by a double Schechter function due to the presence of a statistically significant upturn at the faint-end. The amplitude of this upturn ($\alpha_{f} = -1.58^{+0.19}_{-0.15}$), however, is much smaller than that of the SDSS composite photometric cluster LF by Popesso et al. 2006, $\alpha_{f} \sim$ -2. The faint-end slope of the LF in A85 is consistent, within the uncertainties, with that of the field. The red galaxy population dominates the LF at low luminosities, and is the main responsible for the upturn. The fact that the slopes of the spectroscopic LFs in the field and in a cluster as massive as A85 are similar suggests that the cluster environment does not play a major role in determining the abundance of low-mass galaxies.