NOAO >   Observing Info >   Approved Programs >   2002A-0275

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Proposal Information for 2002A-0275


PI: Ian Dell'Antonio, Brown University, ian@het.brown.edu
Address: Box 1843, Providence, RI 02912, USA

CoI: Luigi Guzzo, Osservatorio di Brera
CoI: Marcella Longhetti, Osservatorio di Brera
CoI: Alberto Moretti, Osservatorio di Brera
CoI: Sergio Campana, Osservatorio di Brera
CoI: Davide Lazzati, Cambridge University
CoI: MariaRosa Panzera, Osservatorio di Brera
CoI: Gianpiero Tagliaferri, Osservatorio di Brera

Title: Distant Compact Clusters of Galaxies from the BMW survey

Abstract: We propose to use SQIID to identify high-redshift clusters of galaxies from the BMW, an X-ray selected sample of serendipitously detected extended sources from the ROSAT HRI archive. The BMW survey is unique because of the superior angular resolution of the HRI. In fact, this is the only modern sample of distant clusters available that is not based on the low-resolution PSPC. Using 4m optical imaging, we have already identified several high-redshift clusters, two of which have z>0.8, thus confirming the ability of the survey to peer efficiently into the z~ 1 regime, where only a handful of X-ray clusters are known. To test the evolution of the cluster abundance, we must increase the number of clusters known in this redshift regime. The BMW survey provides us with the only current opportunity to study compact clusters missing in all PSPC surveys. Because z~ 1 ellipticals have very red colors, K-band imaging is the most effective way of identifying these clusters. With SQIID, we also can obtain redshift estimates via the J-K red sequence. We propose near-IR imaging in J,H,K of 30 highest-z cluster candidates from the BMW survey, as indicated by their small size and low flux. This will allow efficient use of 8-meter spectroscopy to follow up the high-end tail of the redshift distribution.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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