NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-26 T00:21:13 PDT
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For refcode 2006MNRAS.366..953B:
Retrieve 23 NED objects in this reference.
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NED Abstract

Copyright by Royal Astronomical Society. 2006MNRAS.366..953B Multiwavelength XMM-Newton observations of the Laor et al. sample of PG quasars Brocksopp, C.; Starling, R. L. C.; Schady, P.; Mason, K. O.; Romero-Colmenero, E.; Puchnarewicz, E. M. Abstract. We present XMM-Newton/EPIC spectra for the Laor et al. sample of Palomar Green (PG) quasars. We find that a power law provides a reasonable fit to the 2-5 keV region of the spectra. Excess soft X-ray emission below 2 keV is present for all objects, with the exception of those known to contain a warm absorber. However, a single power law is a poor fit to the 0.3-10.0 keV spectrum and instead we find that a simple model, consisting of a broken power law (plus an iron line), provides a reasonable fit in most cases. The equivalent width of the emission line is constrained in just 12 objects but with low (<2{sigma}) significance in most cases. For the sources whose spectra are well fitted by the broken-power-law model, we find that various optical and X-ray line and continuum parameters are well correlated; in particular, the power-law photon index is well correlated with the FWHM of the Hbeta line and the photon indices of the low- and high-energy components of the broken power law are well correlated with each other. These results suggest that the 0.3-10 keV X-ray emission shares a common (presumably non-thermal) origin, as opposed to suggestions that the soft excess is directly produced by thermal disc emission or via an additional spectral component. We present XMM-Newton Optical Monitor (OM) data, which we combine with the X-ray spectra so as to produce broad-band spectral energy distributions (SEDs), free from uncertainties due to long-term variability in non-simultaneous data. Fitting these optical-UV spectra with a Comptonized disc model indicates that the soft X-ray excess is independent of the accretion disc, confirming our interpretation of the tight correlation between the hard and soft X-ray spectra. Key words: galaxies: active, quasars: general, X-rays: galaxies
Retrieve 23 NED objects in this reference.
Please click here for ADS abstract

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