XMM observations of the narrow-line QSO PHL 1092: Detection of a high and variable soft component

Abstract

We present results based on an XMM-Newton observation of the high luminosity narrow-line QSO PHL 1092 performed in 2003 January. The 0.3 - 10 keV spectrum is well described by a model which includes a power-law (Gamma ~ 2.1) and two blackbody components (kT ~ 130 eV and kT ~ 50 eV). The soft X-ray excess emission is featureless and contributes ~ 80% to the total X-ray emission in the 0.3 - 10 keV band. The most remarkable feature of the present observation is the detection of X-ray variability at very short time scale: the X-ray emission varied by 35% in about 5000 s. We find that this variability can be explained by assuming that only the overall normalization varied during the observation. There was no evidence for any short term spectral variability and the spectral shape was similar even during the ASCA observation carried out in 1997. Considering the high intrinsic luminosity (~ 2x10^45 erg/s) and the large inferred mass of the putative black hole (~ 1.6x10^8 M_sun), the observed time scale of variability indicates emission at close to Eddington luminosity arising from very close to the black hole. We suggest that PHL 1092 in particular (and narrow line Seyfert galaxies in general) is a fast rotating black hole emitting close to its Eddington luminosity and the X-ray emission corresponds to the high-soft state seen in Galactic black hole sources.

7 figures, 8 pages, emulateapj style, ApJ in press

References in corpus (7)

• Combined Long and Short Timescale X-ray Variability of NGC4051 with RXTE and XMM-Newton
• XMM-Newton EPIC observations of 21 low-redshift PG quasars
• Slim Disks with Transition Regions and Applications to Microquasars and Narrow Line Seyfert 1 Galaxies
• Arakelian 564: An XMM-Newton view
• An intense soft-excess and evidence for light bending in the luminous narrow-line quasar PHL 1092
• Iron Kalpha emission from the low-luminosity Active Galaxies M81 and NGC 4579
• The Correlation between X-ray spectral slope and FeKalpha line energy in radio-quiet active galactic nuclei

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• Panchromatic Properties of the Extreme FeII Emitter PHL 1092
• PHL 1092 as a transient extreme X-ray weak quasar
• Detection of absorption features in the X-ray spectrum of the narrow-line Quasar PG 1404+226 : Possible evidence for accretion disk winds