The cluster-scale environment of PKS 2155-304

Farina, E.; Fumagalli, M.; Decarli, R.; Fanidakis, N.

doi:10.1093/mnras/stv2277

The cluster-scale environment of PKS 2155-304

Farina, E.; Fumagalli, M.; Decarli, R.; Fanidakis, N.

Authors

E. Farina

Professor Michele Fumagalli michele.fumagalli@durham.ac.uk
Academic Visitor

R. Decarli

N. Fanidakis

Abstract

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 = 0.116 10 ± 0.000 06, consistent with previous determinations of the BL Lac redshift. The galaxy group has a radial velocity dispersion of 250+80−40 km s−1 and a virial radius of 0.22 Mpc, yielding a role-of-thumb estimate of the virial mass of Mvir ∼ 1.5 × 1013 M⊙, i.e. one order of magnitude less than that observed in similar objects. This result hints towards a relatively wide diversity in the environmental properties of BL Lac objects.

Citation

Farina, E., Fumagalli, M., Decarli, R., & Fanidakis, N. (2016). The cluster-scale environment of PKS 2155-304. Monthly Notices of the Royal Astronomical Society, 455(1), 618-625. https://doi.org/10.1093/mnras/stv2277

Journal Article Type	Article
Acceptance Date	Sep 28, 2015
Online Publication Date	Nov 5, 2015
Publication Date	Jan 1, 2016
Deposit Date	Nov 22, 2015
Publicly Available Date	Nov 23, 2015
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	455
Issue	1
Pages	618-625
DOI	https://doi.org/10.1093/mnras/stv2277
Keywords	BL Lacertae objects: individual: PKS 2155−304, Galaxies: groups: general.

Files

Published Journal Article (1.8 Mb)
PDF

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.