2002/12/10 by I. Cagnoni, Cagnoni, I., M. Elvis +9
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0212231
4 pages, 1 table. Proceedings of the 5th Italian AGN Meeting "Inflows, Outflows and Reprocessing around black holes" (2002) on-line edition only available at http://www.merate.mi.astro.it/~gabriele/agn5/agn5.html
arxiv created 2002/12/10 · arxiv updated 2009/12/01
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 two are AGNs. Six more sources are tentatively classified as AGNs on the basis of their X-ray properties and of our optical-IR imaging. For one of the AGNs and for the AGN-like blanks we find a discrepancy between the lack of absorption indicated by the X-ray spectra and the presence of red counterparts in their error circles. We discuss various possibilities to reconcile the X-ray and optical information.