The Cluster-Scale Environment of PKS 2155-304

Autor:	Farina, E. P., Fumagalli, M., Decarli, R., Fanidakis, N.
Rok vydání:	2015
Předmět:	Astrophysics - Astrophysics of Galaxies Astrophysics - Cosmology and Nongalactic Astrophysics
Druh dokumentu:	Working Paper
DOI:	10.1093/mnras/stv2277
Popis:	PKS 2155-304 is one of the brightest extragalactic source in the X-ray and EUV bands, and is a prototype for the BL Lac class of objects. In this paper we investigate the large-scale environment of this source using new multi-object as well as long-slit spectroscopy, together with archival spectra and optical images. We find clear evidence of a modest overdensity of galaxies at z=0.11610, consistent with previous determinations of the BL Lac redshift. The galaxy group has a radial velocity dispersion of 250km/s and a virial radius of 0.22Mpc, yielding a role-of-thumb estimate of the virial mass of M(vir)~1.5x10$^{13}$Msun, i.e., one order of magnitude less than what observed in other similar objects. This result hints toward a relatively wide diversity in the environmental properties of BL Lac objects. Comment: Accepted for publication in MNRAS
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1510.01779 Zobrazit plný text záznamu View this record from Arxiv