Volume 369, Number 2, April II 2001
|Page(s)||450 - 458|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 April 2001|
RX J2217.9-5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy *
MPI für extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany
2 MPI für Astrophysik, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
3 Columbia Astrophysics Laboratory, 538 West 120th St., New York, NY 10027, USA
4 Dept. of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019, USA
Corresponding author: D. Grupe, email@example.com
Accepted: 12 January 2001
We report the discovery of a highly X-ray variable AGN, RX J2217.9-5941. This object was bright during the ROSAT All-Sky Survey (RASS), during which a decrease in the count rate by a factor of 12 was observed. It was found to be much fainter in follow-up HRI observations and is therefore an X-ray transient AGN candidate. On long time scales of years, its count rate decreased by a factor of about 30 between the RASS and the ROSAT HRI and ASCA observations in 1998. Analysis of the ASCA data, complicated by source confusion and poor statistics, tentatively indicates a steep spectrum in the faint state. There is no evidence for variability among 5 optical observations of the object obtained between 1992 and 1998. We discuss the variability of RX J2217.9-5941 and its possible X-ray transient nature.
Key words: accretion, accretion disks / galaxies: active / galaxies: nuclei / galaxies: Seyfert / galaxies: individual (RX J2217.9 / 5941)
© ESO, 2001
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