2 papers
astro-ph2002
AGNs among ROSAT Blank Field Sources
I. Cagnoni, M. Elvis, D. -W. Kim +3
We selected a sample of sources with high X-ray over optical flux ratio from the ROSAT PSPC archives. Out of the 16 sources in our sample, one is a (possibly extreme) BL Lac and tw…
astro-ph2001
Clusters of galaxies among ROSAT blank field sources
I. Cagnoni, M. Elvis, D. -W. Kim +3
We present here an efficient method for selecting high luminosity and massive high redshift clusters of galaxies, crucially important tools in cosmology. By selecting bright and ex…