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The X-Ray Weakness of GPS Radio Galaxies: A Volume-Limited Complete SampleThe XMM observations of Mkn 668 have been analyzed. We found soft X-ray signatures of a hot plasma (kT approximately 10^7 approximately K) and a hard X-ray emission from the nucleus. The X-ray spectrum above 2.5 approximately keV is characterized by a very flat (observed photon index, Gamma approximately 0.5) power-law continuum, alongside with a strong Fe-K-alpha neutral iron fluorescent line (EW approximately 600 approximately eV). The best explanation for the origin of this high energy X-ray emission is in terms of the Compton-reflection of the nuclear emission. The primary X-ray emission is obscured by a Compton-thick (N_H approximately 10^24 approximately cm-2) matter which becomes transparent at higher energies. The observed above 2.5-keV X-rays are mostly due to reflection which is indicated by a strong Fe-K-alpha line. This represents the second hard X-ray detection of the GPS galaxy ever (the first one being 1345+125; O Dea et al. 2000). Interestingly, the both such trend is confirmed by our on going XMM-Newton observations of a larger GPS sample, it would lead us to looking into the question on how the dense nuclear environment impacts the nature and evolution of a GPS source, and more generally, on the history of radio power in the universe. The paper summarizing the results has been submitted to Astronomy and Astrophysics in December 2003.
Document ID
Document Type
Contractor or Grantee Report
Mushotzky, Richard F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Siemiginowska, Aneta (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Date Acquired
August 21, 2013
Publication Date
February 1, 2004
Subject Category
Funding Number(s)
Distribution Limits
Work of the US Gov. Public Use Permitted.
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