Query : 2003A&A...398...81B

2003A&A...398...81B - Astronomy and Astrophysics, volume 398, 81-87 (2003/1-4)

XMM-Newton observation of PG 0844+349.


Abstract (from CDS):

In a ∼20 ksec XMM-Newton observation the X-ray transient radio-quiet quasar PG 0844+349 was found in a historically high state compared to previous X-ray observations. The quasar showed a featureless spectrum with a strong soft excess over the extrapolation of a hard power law. Comptonization models or a broken power law with Γsoft∼2.75, Γhard∼2.25 and a break energy of Ebreak∼1.35keV represent acceptable descriptions of the spectral continuum. In the Comptonization models the temperature of the Comptonizing gas is considerably lower than generally found in (broad line) Seyfert galaxies whereas the optical depth is much higher. As a similar behavior has been seen in NLSy1 galaxies, it might be an indicator of the different physical conditions in these two classes of AGN. During the XMM-Newton observation the flux of PG 0844+349 varied achromatically in a smooth, nearly linear fashion, by ∼25% on time scales of a few thousand seconds, which puts some constraints on current models of Comptonizing accretion disk coronae.

Abstract Copyright:

Journal keyword(s): galaxies: active - quasars: individual: PG 0844+349 - X-rays: galaxies

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 QSO B0558-5026 BLL 05 59 47.3917733375 -50 26 52.026945176   15.18 14.97     ~ 256 1
2 Ton 951 Sy1 08 47 42.4487014731 +34 45 04.483113429   14.83 14.50     ~ 434 0

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