Evidence for Rapid Redshift Evolution of Strong Cluster Cooling Flows

Дата и время публикации : 2011-01-25T22:12:27Z

Авторы публикации и институты :
R. Samuele (Northrop Grumman)
B. R. McNamara (U.Waterloo & Perimeter Institute)
A. Vikhlinin (CfA)
C. R. Mullis (ESO)

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: Accepted for publication in ApJ
Первичная категория: astro-ph.CO

Все категории : astro-ph.CO

Краткий обзор статьи: We present equivalent widths of the [OII] and Ha nebular emission lines for 77 brightest cluster galaxies (BCGs) selected from the 160 Square Degree $ROSAT$ X-ray survey. We find no [OII] or Ha emission stronger than -15 angstroms or -5 angstroms, respectively, in any BCG. The corresponding emission line luminosities lie below 6E40 erg/s, which is a factor of 30 below that of NGC1275 in the Perseus cluster. A comparison to the detection frequency of nebular emission in BCGs lying at redshifts above z = 0.35 drawn from the Brightest Cluster Survey (Crawford et al. 1999) indicates that we should have detected roughly one dozen emission-line galaxies, assuming the two surveys are selecting similar clusters in the X-ray luminosity range 10E42 erg/s to 10E45 erg/s. The absence of luminous nebular emission (ie., Perseus-like systems) in our sample is consistent with an increase in the number density of {it strong} cooling flow (cooling core) clusters between $rm z=0.5$ and today. The decline in their numbers at higher redshift could be due to cluster mergers and AGN heating.

Category: Physics