Deep X-ray surveys of galaxy clusters covering large solid angles offer ideal samples for studying the evolution of the large scale structure in the Universe. I review here some recent results from the ROSAT Deep Cluster Survey (RDCS), particularly, on the study of the evolution of the abundance of galaxy clusters over a large redshift range. The optical identification of RDCS sources have revealed a significant fraction of clusters at z > 0.5. The observed X-ray Luminosity Function out to z similar or equal to 0.8 and the faint cluster number counts from the RDCS, when combined with previous results of the Einstein Extended Medium Sensitivity Survey, provide a much improved observational picture of the evolution of clusters in the X-ray band, revealing a slowly evolving population of galaxy clusters since at least z similar or equal to 0.8. The theoretical interpretation of these findings in the framework of theories of structure formation will still be subject of much debate in the years to come. The construction of large samples of clusters out to z similar to 1 and beyond appears to be a challenging task even with the next generation of X-ray satellites (AXAF, XMM).
Results from the ROSAT Deep Cluster Survey
ROSATI, Piero
1998
Abstract
Deep X-ray surveys of galaxy clusters covering large solid angles offer ideal samples for studying the evolution of the large scale structure in the Universe. I review here some recent results from the ROSAT Deep Cluster Survey (RDCS), particularly, on the study of the evolution of the abundance of galaxy clusters over a large redshift range. The optical identification of RDCS sources have revealed a significant fraction of clusters at z > 0.5. The observed X-ray Luminosity Function out to z similar or equal to 0.8 and the faint cluster number counts from the RDCS, when combined with previous results of the Einstein Extended Medium Sensitivity Survey, provide a much improved observational picture of the evolution of clusters in the X-ray band, revealing a slowly evolving population of galaxy clusters since at least z similar or equal to 0.8. The theoretical interpretation of these findings in the framework of theories of structure formation will still be subject of much debate in the years to come. The construction of large samples of clusters out to z similar to 1 and beyond appears to be a challenging task even with the next generation of X-ray satellites (AXAF, XMM).I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
