A Search for x-ray bright distant clusters of galaxies

Journal Article · Tue Mar 01 04:00:00 EST 1994 · Astrophys.J.

DOI:https://doi.org/10.1086/174585· OSTI ID:1847824

Nichol, R. C. ^[1]; Ulmer, M. P. ^[1]; Kron, R. G. ^[2]; Wirth, G. D. ^[3]; Koo, D. C. ^[4]

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1. Northwestern U.
2. Fermilab
3. UC, Santa Cruz
4. Lick Observ.; UC, Santa Cruz

We present the results of a search for X--ray luminous distant clusters of galaxies. We found extended X--ray emission characteristic of a cluster towards two of our candidate clusters of galaxies. They both have a luminosity in the ROSAT bandpass of $$\simeq10^{44}{\rm \,erg\,s^{-1}}$$ and a redshift of $>0.5$: thus making them two of the most distant X--ray clusters ever observed. Furthermore, we show that both clusters are optically rich and have a known radio source associated with them. We compare our result with other recent searches for distant X--ray luminous clusters and present a lower limit of $$1.2\times10^{-7}\,{\rm Mpc^{-3}}$$ for the number density of such high redshift clusters. This limit is consistent with the expected abundance of such clusters in a standard (b=2) Cold Dark Matter Universe. Finally, our clusters provide important high redshift targets for further study into the origin and evolution of massive clusters of galaxies. Accepted for publication in the 10th September 1994 issue of ApJ.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 1847824
• Report Number(s): FERMILAB-PUB-94-439-A; arXiv:astro-ph/9403033; oai:inspirehep.net:390422
• Journal Information: Astrophys.J., Journal Name: Astrophys.J. Vol. 432
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS