2006/11/20 by Xin-Lin Zhou, Fang Yang, Xiaorong Lu +3
Physics and Astronomy · #Absorption (acoustics) #Art #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Black-body radiation #EPIC #Galaxies: Formation, Evolution, Phenomena #Galaxy #Geometry #Line (geometry) #Literature #Optics #Photon #Physics #Quasar #Spectral line #astro-ph
paper · pdf · doi:10.1086/510152
published as Astron.J.133:432-438,2007 · 23 pages, 8 figures, AJ in press
arxiv created 2006/11/20 · openalex publication_date 2006/12/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/08
We present an XMM-Newton EPIC observation of HE 0450-2958, which may be a "naked" quasar as suggested by Magain and coworkers. The XMM-Newton EPIC spectra show a substantial soft X-ray excess and a steep photon index, as well as marginal evidence for a weak Fe Kα line. The X-ray absorption is consistent with the Galactic level. The 0.3-10 keV EPIC spectra can be fitted by a power-law plus blackbody model; however, the fit by a relativistically blurred photoionized disk reflection model is better. We estimate a black hole mass of 2 × 10 7 M ⊙ from the X-ray variability. This broadly agrees with the value derived from the optical Hβ line width. These results support a high-state Seyfert galaxy as the source. HE 0450-2958 shares properties with transitionary objects from ultraluminous infrared galaxies to quasars. We suggest that HE 0450-2958 is just in the beginning of an optical quasar window.