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X-ray variability in a complete sample of Soft X-ray selected AGN

D. Grupe·H. -C. Thomas·K. Beuermann
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Abstract

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 WPVS007. We discuss possible models to explain the X-ray transience and the variabilities observed in the non-transient sources.

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D. Grupe, H. -C. Thomas, K. Beuermann. 2000-12-05. X-ray variability in a complete sample of Soft X-ray selected AGN. https://doi.org/10.1051/0004-6361%3A20000429

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