# Properties and environment of Radio Emitting Galaxies in the VLA-zCOSMOS survey - Astrophysics > Cosmology and Nongalactic Astrophysics

Properties and environment of Radio Emitting Galaxies in the VLA-zCOSMOS survey - Astrophysics > Cosmology and Nongalactic Astrophysics - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We investigate the properties and the environment of radio sources withoptical counterpart from the combined VLA-COSMOS and zCOSMOS samples. Theadvantage of this sample is the availability of optical spectroscopicinformation, high quality redshifts, and accurate density determination.By comparing the star formation rates estimated from the optical spectralenergy distribution with those based on the radio luminosity, we divide theradio sources in three families, passive AGN, non-passive AGN and star forminggalaxies. These families occupy specific regions of the 8.0-4.5 $\mu$m infraredcolor-specific star formation plane, from which we extract the correspondingcontrol samples.Only the passive AGN have a significantly different environment distributionfrom their control sample. The fraction of radio-loud passive AGN increasesfrom ~2% in underdense regions to ~15% for overdensities 1+delta greater than10. This trend is also present as a function of richness of the groups hostingthe radio sources. Passive AGN in overdensities tend to have higher radioluminosities than those in lower density environments. Since the black holemass distribution is similar in both environments, we speculate that, for lowradio luminosities, the radio emission is controlled through fueldisponibility or confinement of radio jet by local gas pressure by theinterstellar medium of the host galaxy, while in other cases it is determinedby the structure group or cluster in which the galaxy resides.

Autor: S.Bardelli, E.Schinnerer, V.Smolcic, G.Zamorani, E.Zucca, M.Mignoli, C.Halliday, K.Kovac, P.Ciliegi, K.Caputi, A.M.Koekemoer, A.B

Fuente: https://arxiv.org/