The Warps Survey for Faint Clusters of Galaxies
نویسندگان
چکیده
The WARPS cluster survey is based on the ROSAT PSPC archive of pointed observations. It includes extended X-ray sources, detected with the Voronoi Tessel-lation and Percolation algorithm (VTP), and point-like X-ray sources with non-stellar optical counterparts. It is designed to minimize selection eeects whilst covering a large area of sky. The aims of the survey are to (a) measure the low luminosity (<10 44 erg s 1), high redshift (z>0.2) X-ray luminosity function of clusters and groups, and (b) investigate cluster morphologies and unusual systems (eg merging clusters). In an initial 13 sq deg (66 elds) we have found 22 extended X-ray sources with detected ux >7x10 14 erg cm 2 s 1 (0.5-2 keV) and sizes of 1 to 5 arcmin. Optically, they range from a single bright nearby galaxy which has been resolved, an Abell cluster which is revealed to have two (probably merging) components, and groups and clusters of galaxies at estimated redshifts beyond z=0.4.
منابع مشابه
DASTWAR: a tool for completeness estimation in magnitude-size plane
Today, great observatories around the world, devote a substantial amount of observing time to sky surveys. The resulted images are inputs of source finder modules. These modules search for the target objects and provide us with source catalogues. We sought to quantify the ability of detection tools in recovering faint galaxies regularly encountered in deep surveys. Our approach was based on com...
متن کاملAn optical and near-IR survey of nearby clusters of galaxies
We present an optical and near–infrared survey of galaxies in nearby clusters aimed at determining fundamental quantities of galaxies, such as multivariate luminosity function and color distribution for each Hubble type. The main characteristics of our survey are completeness in absolute magnitude, wide wavelength coverage and faint limiting magnitudes.
متن کاملThe Build–up of the Red–sequence in Galaxy Clusters since Z ∼ 0.8 *
We study the rest–frame (U−V) color–magnitude relation in 4 clusters at redshifts 0.7–0.8, drawn from the ESO Distant Cluster Survey. We confirm that red–sequence galaxies in these clusters can be described as an old, passively–evolving population and we demonstrate, by comparison with the Coma cluster, that there has been significant evolution in the stellar mass distribution of red–sequence g...
متن کاملTHE WARPS X-RAY SURVEY OF GALAXIES, GROUPS AND CLUSTERS – I. Method and first results
We have embarked on a survey of ROSAT PSPC archival data with the aim of detecting all significant surface brightness enhancements due to sources in the innermost R ≤ 15 arcmin of the PSPC field of view in the energy band 0.5− 2.0 keV. This project is part of the Wide Angle ROSAT Pointed Survey (WARPS) and is designed primarily to measure the low luminosity, high redshift, X-ray luminosity func...
متن کاملCross - correlation of the unresolved X - ray background with faint galaxies
At the faint end of the deepest X-ray surveys, a population of X-ray luminous galaxies is seen. In this paper, we present the results of a cross-correlation between the residual, unresolved X-ray photons in a very deep X-ray survey and the positions of faint galaxies, in order to examine the importance of these objects at even fainter flux levels. We measure a significant correlation on all ang...
متن کامل