Riccardo Giacconi

Learn More
We present the results of our spectroscopic follow-up program of the X-ray sources detected in the 942 ks exposure of the Chandra Deep Field South (CDFS). 288 possible counterparts were observed at the VLT with the FORS1/FORS2 spectrographs for 251 of the 349 Chandra sources (including three additional faint X-ray sources). Spectra and R-band images are(More)
1 Results reported here are based on observations made with the Multiple Mirror Telescope, a joint facility of the Smithonian Institution and the University of Arizona ABSTRACT In the construction of an X-ray selected sample of galaxy clusters for cosmological studies, we have assembled a sample of 495 X-ray sources found to show extended X-ray emission in(More)
The ROSAT Deep Survey in the Lockman Hole is the most sensitive X-ray survey performed to date, encompassing an exposure time of 207 ksec with the PSPC and a total of 1.32 Msec with the HRI aboard ROSAT. Here we present the complete catalogue of 50 X-ray sources with PSPC fluxes (0.5-2 keV) above 5.5 × 10 −15 erg cm −2 s −1. The optical identifications are(More)
We present the X-ray Luminosity Function (XLF) of the ROSAT Deep Cluster Survey (RDCS) sample over the redshift range 0.05–0.8. Our results are derived from a complete flux-limited subsample of 70 galaxy clusters, representing the brightest half of the total sample, which have been spectroscopically identified down to the flux limit of 4 × 10 −14 erg cm −2(More)
We present our first results from 130 ks of X–ray observations obtained with the Advanced CCD Imaging Spectrometer on the Chandra X–ray Observatory. The field of the two combined exposures is 0.096 square degrees and the detection limit is to a S/N ratio of 2 (corresponding to ∼ 7 net counts). We reach a flux of 2 × 10 −16 erg s −1 cm −2 in the 0.5–2 keV(More)
An unusual double-lobed extended X-ray source (RX J105343+5735) is detected in the ROSAT ultra-deep HRI image of the Lockman Hole. The angular size of the source is 1.7 × 0.7 arcmin 2 and its X-ray flux is 2 × 10 −14 erg cm −2 s −1. R-band imaging from the Keck telescope revealed a marginal excess of galaxies brighter than R=24.5, but Keck LRIS(More)
JOHNS HOPKINS UNIVERSITY PRESS publishes books in science, history, literature, health, and medicine. Founded in 1878, the Press publishes about 200 new titles each year and maintains an active backlist of more than 3,500 titles. Generic The Unbranding of Modern Medicine Jeremy A. Greene " An enlightening and passionately written work, Generic opens the(More)
We present the rst results of a serendipitous search for clusters of galaxies in deep ROSAT-PSPC pointed observations at high galactic latitude. The survey is being carried out using a Wavelet based Detection Algorithm which is not biased against extended, low surface brightness sources. A new ux{diameter limited sample of 10 cluster candidates has been(More)