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X-Ray Weak Broad-Line Quasars: Absorption or Intrinsic X-Ray WeaknessXMM observations of X-ray weak quasars have been performed during 2003. The data for all but the last observation are now available (there has been a delay of several months on the initial schedule, due to high background flares which contaminated the observations: as a consequence, most of them had to be rescheduled). We have reduced and analyzed these data, and obtained interesting preliminary scientific results. Out of the eight sources, 4 are confirmed to be extrimely X-ray weak, in agreement with the results of previous Chandra observations. 3 sources are confirmed to be highly variable both in flux (by factors 20-50) and in spectral properties (dramatic changes in spectral index). For both these groups of objects, an article is in preparation. Preliminary results have been presented at an international workshop on AGN surveys in December 2003, in Cozumel (Mexico). In order to further understand the nature of these X-ray weak quasars, we submitted proposals for spectroscopy at optical and infrared telescopes. We obtained time at the TNG 4 meter telescope for near-IR observations, and at the Hobby-Eberly Telescope for optical high-resolution spectroscopy. These observations will be performed in early 2004, and will complement the XMM data, in order to understand whether the X-ray weakness of these sources is an intrinsic property or is due to absorption by circumnuclear material.
Document ID
20040016144
Acquisition Source
Goddard Space Flight Center
Document Type
Contractor or Grantee Report
Authors
Risaliti, Guido
(Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Mushotzky, Richard F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Astrophysics
Report/Patent Number
Rept-1
Funding Number(s)
CONTRACT_GRANT: NAG5-12932
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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