Fossil group origins - VI. Global X-ray scaling relations of fossil galaxy clusters

Abstract

We present the first pointed X-ray observations of 10 candidate fossil galaxy groups and clusters. With these Suzaku observations, we determine global temperatures and bolometric X-ray luminosities of the intracluster medium (ICM) out to $r_{500}$ for six systems in our sample. The remaining four systems show signs of significant contamination from non-ICM sources. For the six objects with successfully determined $r_{500}$ properties, we measure global temperatures in the range $2.8\le T_{\mathrm{X}}\le 5.3\mathrm{keV}$, bolometric X-ray luminosities of $0.8\times 10^{44}\le L_{\mathrm{X},\mathrm{bol}}\le 7.7\times 10^{44}\mathrm{erg}{\mathrm{s}}^{-1}$, and estimate masses, as derived from $T_{\mathrm{X}}$, of $M_{500}>10^{14}{\mathrm{M}}_{\odot }$. Fossil cluster scaling relations are constructed for a sample that combines our Suzaku observed fossils with fossils in the literature. Using measurements of global X-ray luminosity, temperature, optical luminosity, and velocity dispersion, scaling relations for the fossil sample are then compared with a control sample of non-fossil systems. We find the fits of our fossil cluster scaling relations are consistent with the relations for normal groups and clusters, indicating fossil clusters have global ICM X-ray properties similar to those of comparable mass non-fossil systems.

17 pages, 7 figures, 8 tables. Accepted for publication in MNRAS