We present a deep X-ray selected sample of galaxy clusters which has been created from a serendipitous search in ROSAT-PSPC deep pointed observations at high galactic latitude. This survey, hereafter known as the ROSAT Deep Cluster Survey (RDCS), is being carried out utilizing a wavelet-based detection algorithm which, unlike other detection methods, is not biased against extended, low surface brightness sources. It is a flux-diameter Limited sample that extends the X-ray flux limit of previous cluster surveys by more than one order of magnitude (F-X greater than or equal to 1.10(-14)erg cm(-2)s(-1)). The first results of the on-going optical follow-up program indicate a high success rate of identification. At the present, 38 clusters out of 80 candidates have been identified on a 26 deg(2) surveyed area. Recently measured redshifts confirm the nature of these systems as low-moderate redshift groups (z similar or equal to 0.2-0.3) and intermediate to high redshift clusters (z similar or equal to 0.4-0.7). We show X-ray and optical images of several clusters identified to date, discuss the X-ray properties of the sample and present preliminary results on the redshift distribution. The final sample will include similar to 100 clusters covering and area of similar to 40 deg(2).
A serendipitous deep cluster survey from ROSAT-PSPC pointed observations
ROSATI, Piero
1997
Abstract
We present a deep X-ray selected sample of galaxy clusters which has been created from a serendipitous search in ROSAT-PSPC deep pointed observations at high galactic latitude. This survey, hereafter known as the ROSAT Deep Cluster Survey (RDCS), is being carried out utilizing a wavelet-based detection algorithm which, unlike other detection methods, is not biased against extended, low surface brightness sources. It is a flux-diameter Limited sample that extends the X-ray flux limit of previous cluster surveys by more than one order of magnitude (F-X greater than or equal to 1.10(-14)erg cm(-2)s(-1)). The first results of the on-going optical follow-up program indicate a high success rate of identification. At the present, 38 clusters out of 80 candidates have been identified on a 26 deg(2) surveyed area. Recently measured redshifts confirm the nature of these systems as low-moderate redshift groups (z similar or equal to 0.2-0.3) and intermediate to high redshift clusters (z similar or equal to 0.4-0.7). We show X-ray and optical images of several clusters identified to date, discuss the X-ray properties of the sample and present preliminary results on the redshift distribution. The final sample will include similar to 100 clusters covering and area of similar to 40 deg(2).I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
