$XMM-Newton$ $Î©$ project: III. Gas mass fraction shape in high redshift clusters

Rachida Sadat; Alain Blanchard; Sebastien C. Vauclair; David H. Lumb; James Bartlett; A. K. Romer; Jean-Philippe Bernard; Michel Boer; Philippe Marty; Jukka Nevalainen; Douglas J. Burke; C. A. Collins; Robert C. Nichol

paper

$X M M - N e w t o n$ $I^c ◯$ project: III. Gas mass fraction shape in high redshift clusters

arXiv:astro-ph/0503426

Abstract

We study the gas mass fraction, $f_gas,$ behavior in $X M M - N e w t o n$ $I^c ◯$ project. The typical $f_gas$ shape of high redshift galaxy clusters follows the global shape inferred at low redshift quite well. This result is consistent with the gravitational instability picture leading to self similar structures for both the dark and baryonic matter. However, the mean $f_gas in d i s t an t c l u s t er ss h o w sso m e d i f f er e n ces t o l oc a l o n es, in d i c a t in g a d e p a r t u r e f r o m s t r i c t sc a l in g . T hi sr es u l t i sco n s i s t e n tw i t h t h eo b ser v e d e v o l u t i o nin t h e l u min os i t y - t e m p er a t u r er e l a t i o n . W e q u an t i t a t i v e l y in v es t i g a t e t hi s d e p a r t u r e f r o m sc a l in g l a w s . W i t hin t h e l oc a l s am pl e w e u se d, am o d er a t e b u t c l e a r v a r ia t i o n o f t h e am pl i t u d eo f t h e g a s ma ss f r a c t i o n w i t h t e m p er a t u r e i s f o u n d, a t r e n d t ha tw e ak e n s in t h eo u t er r e g i o n s . T h ese v a r ia t i o n s d o n o t e x pl ain d e p a r t u r e f r o m sc a l in g l a w so f o u r d i s t an t c l u s t er s . A nim p or t an t im pl i c a t i o n o f o u r r es u l t s i s t ha tt h e g a s f r a c t i o n e v o l u t i o n, a t es t o f t h ecos m o l o g i c a l p a r am e t er s, c an l e a d t o bia se d v a l u es w h e na ppl i e d a t r a d ii s ma l l er t han t h e v i r ia l r a d i u s . F r o m o u r$ XMM$ clusters, the apparent gas fraction at the virial radius is consistent with a non-evolving universal value in a high matter density model and not with a concordance.

Accepted, A&A, in press

XMM−Newton I^c◯ project: III. Gas mass fraction shape in high redshift clusters

Abstract

$X M M - N e w t o n$ $I^c ◯$ project: III. Gas mass fraction shape in high redshift clusters