2011/03/08 by Thomas Böller, Th. Boller, P. Schady +1
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Brightness #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Optics #Photon #Physics #ROSAT #astro-ph.CO
paper · pdf · doi:10.1088/2041-8205/731/1/l16
5 pages, 3 figures, accepted for publication in ApJ Letters
arxiv created 2011/03/08 · openalex publication_date 2011/03/21 · arxiv updated 2015/05/27 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/05
We have analyzed the first XMM-Newton , Swift , and archival ROSAT PSPC observations of the quasar LBQS 0102-2713. The object was selected from the ROSAT archive as being notable due to the steep soft X-ray photon index and due to the UV brightness based on Hubble Space Telescope and optical spectroscopic observations. The first XMM-Newton observations carried out in 2009 December and the first Swift observations from 2010 have confirmed the steepness of the soft X-ray photon index, which ranges between 3.35 and 4.41 for the different XMM-Newton and ROSAT detectors, the UV brightness of the source, and the absence of significant absorption by neutral hydrogen. The new data allow a combined spectral fitting to the Swift Ultra-Violet/Optical Telescope and the XMM-Newton / ROSAT data which results in a huge luminosity of (6.2 ± 0.2) × 10 47 erg s −1 and α ox values ranging between (−1.87 ± 0.11) and(−2.11 ± 0.12). The nature of the soft X-ray emission can be explained as local Comptonized emission of the UV disk photons in the pseudo-Newtonian potential. The black hole mass is estimated from the Mg ii line and translates into an Eddington ratio of L / L edd = 18 +33 −12 . For the dimensionless electron temperature of the plasma cloud θ = kT e / m e c 2 we derive an upper limit of about 10 keV.