AEGIS: Chandra observation of DEEP2 galaxy groups and clusters

作者：Fang Taotao^*; Gerke Brian F; Davis David S; Newman Jeffrey A; Davis Marc; Nandra Kirpal; Laird Elise S; Koo David C; Coil Alison L; Cooper Michael C; Croton Darren J; Yan Renbin

来源：Astrophysical Journal, 2007, 660(1): L27-L30.

DOI：10.1086/517924

• cosmology : observations
• intergalactic medium
• large-scale structure of universe
• surveys
• X-rays : galaxies : clusters

We present a 200 ks Chandra observation of seven spectroscopically selected, high-redshift (0.75 < z < 1.03) galaxy groups and clusters discovered by the DEEP2 Galaxy Redshift Survey in the Extended Groth Strip. Xray emission at the locations of these systems is consistent with background. The 3 sigma upper limits on the bolometric X-ray luminosities (L-X) of these systems put a strong constraint on the relation between and the L-X and the velocity dispersion of member galaxies sigma(gal) at z similar to 1; the DEEP2 systems have lower luminosity than would be predicted by the local relation. Our result is consistent with recent findings that at high redshift, optically selected clusters tend to be X-ray-underluminous. A comparison with mock catalogs indicates that it is unlikely that this effect is entirely caused by a measurement bias between and the dark matter velocity dispersion. Physically, the DEEP2 systems may still be in the process of forming and hence not fully virialized, or they may be deficient in hot gas compared to local systems. We find only one possibly extended source in this Chandra field, which happens to lie outside the DEEP2 coverage.

• 出版日期2007-5-1