Astronomy and Astrophysics – Astrophysics
Scientific paper
1995-12-08
Astronomy and Astrophysics
Astrophysics
2 pages, postscript, to appear in Proc. of "Roentgenstrahlung from the Universe", 25-29 Sep 1995, Wuerburg, Germany
Scientific paper
We report some remarkable and unexpected results of optical/UV/X-ray follow-up observations of bright soft X-ray selected AGN from the ROSAT All-Sky-Survey. The majority of these AGN are rather anonymous Seyfert galaxies, mostly of the narrow-line Seyfert 1 subtype (nlSy1). We confirm the well-known X-ray variability by factors of a few. However, we also found strikingly different variability patterns: (i) a drop in the PSPC count rate by a factor of ~400 in WPVS007, (ii) a bolometrically dominant soft X-ray component decreasing in flux by a factor ~100 in IC 3599 accompanied by a decrease in optical emission line fluxes, and (iii) a drastic X-ray spectral change in RX J0134-42 from ultrasoft to a typical hard Seyfert spectrum. These dramatic variations occur within a (few) year(s), implying that the accretion flow in the immediate vicinity of the central black hole must have undergone a major change. We discuss possible physical explanations such as accretion disk instabilities or the tidal disruption of stars.
Beuermann Klaus
Fink Henner
Grupe Dirk
Mannheim Karl
Thomas Hans-Christoph
No associations
LandOfFree
Ultrasoft transient X-ray emission from AGN does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Ultrasoft transient X-ray emission from AGN, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ultrasoft transient X-ray emission from AGN will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-632867