SIMBAD references

2001A&A...367..470G - Astronomy and Astrophysics, volume 367, 470-486 (2001/2-4)

X-ray variability in a complete sample of soft X-ray selected AGN.


Abstract (from CDS):

We present ROSAT All-Sky Survey and ROSAT pointed observations (PSPC and HRI) of a complete sample of 113 bright soft X-ray AGN selected from the ROSAT Bright Source Catalog. We compare these observations in order to search for extreme cases of flux and spectral X-ray variability - X-ray transient AGN. Three definite transients and one transient candidate are found. The other sources show amplitude variations typically by factors of 2-3 on timescales of years. We found that the variability strength on timescales of days is a function of the steepness of the X-ray spectrum: steeper X-ray objects show stronger variability than flat X-ray spectrum sources. We also present new HRI measurements of our extreme X-ray transients IC 3599 and WPVS 007. We discuss possible models to explain the X-ray transience and the variabilities observed in the non-transient sources.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - galaxies: active - galaxies: nuclei of - galaxies: Seyfert - quasars: general

CDS comments: misprint 1H 0419+577 instead of 1H 0419-577

Simbad objects: 118

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