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ROSAT HRI monitoring of X-ray variability in the NLS1 galaxy PKS 0558-504

M. Gliozzi·Th. Boller·W. Brinkmann·W. N. Brandt
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Abstract

We present the results of ROSAT High Resolution Imager (HRI) observations and the survey data of the radio-loud Narrow-Line Seyfert 1 galaxy (NLS1) PKS 0558--504. We find strong and persistent X-ray variability on both short and medium time-scales. The most extreme amplitude variations require a radiative efficiency exceeding the theoretical maximum for a Schwarzschild black hole, suggesting the presence of a rotating black hole or the influence of relativistic beaming effects. The spatial analysis rules out the possibility that the high luminosity and the strong variability are related to a nearby source.

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M. Gliozzi, Th. Boller, W. Brinkmann, W. N. Brandt. 2000-03-02. ROSAT HRI monitoring of X-ray variability in the NLS1 galaxy PKS 0558-504. https://arxiv.org/abs/astro-ph/0003023

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