An XMM-Newton observation of the massive, relaxed galaxy cluster ClJ1226.9+3332 at z=0.89

B. J. Maughan, L. R. Jones, H. Ebeling, C. Scharf

Research output: Contribution to journalArticle (Academic Journal)peer-review

38 Citations (Scopus)
240 Downloads (Pure)


A detailed X-ray analysis of an XMM-Newton observation of the high-redshift (z=0.89) galaxy cluster ClJ1226.9+3332 is presented. The X-ray temperature is found to be 11.5{+1.1}{-0.9}keV, the highest X-ray temperature of any cluster at z>0.6. In contrast to MS1054-0321, the only other very hot cluster currently known at z>0.8, ClJ1226.9+3332 features a relaxed X-ray morphology, and its high overall gas temperature is not caused by one or several hot spots. The system thus constitutes a unique example of a high redshift, high temperature, relaxed cluster, for which the usual hydrostatic equilibrium assumption, and the X-ray mass is most reliable. A temperature profile is constructed (for the first time at this redshift) and is consistent with the cluster being isothermal out to 45% of the virial radius. Within the virial radius (corresponding to a measured overdensity of a factor of 200), a total mass of (1.4+/-0.5)*10^15 M_solar is derived, with a gas mass fraction of 12+/-5%. The bolometric X-ray luminosity is (5.3+/-0.2)*10^45 erg/s. The probabilities of finding a cluster of this mass within the volume of the discovery X-ray survey are 8*10^{-5} for Omega_M=1 and 0.64 for Omega_M=0.3, making Omega_M=1 highly unlikely. The entropy profile suggests that entropy evolution is being observed. The metal abundance (of Z=0.33{+0.14}{-0.10} Z_solar), gas mass fraction, and gas distribution are consistent with those of local clusters; thus the bulk of the metals were in place by z=0.89.
Original languageEnglish
Pages (from-to)1193-1203
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Early online date22 Mar 2004
Publication statusPublished - 11 Jul 2004

Bibliographical note

13 pages, 8 figures. Accepted for publication in MNRAS


  • astro-ph


Dive into the research topics of 'An XMM-Newton observation of the massive, relaxed galaxy cluster ClJ1226.9+3332 at z=0.89'. Together they form a unique fingerprint.

Cite this