Astron. Astrophys. 349, L45-L48 (1999)

4. Summarizing conclusions

We have reported the detection of a giant X-ray outburst from the previously unknown galaxy pair RX J1242.6-1119. The outburst X-ray spectrum is very soft (photon index ) and luminous ( erg s^-1), whereas the optical spectra of both galaxies do not show evidence for Seyfert activity. We therefore suggest that RX J1242-11 is another of the rare cases of giant UV/X-ray outbursts from non-active galaxies. The X-ray variability is most likely linked to an accretion event - e.g., by the tidal disruption of a star as predicted by Rees (1988) - on a SMBH residing in the center of one of the two galaxies.

Such X-ray outbursts thus provide important information on the presence of SMBHs in non-active galaxies, the accretion history of the universe, and the link between active and normal galaxies. Further exploitation of the ROSAT data base and future X-ray surveys (like the one that was planned with ABRIXAS ) will be very valuable in finding further of these outstanding sources.

© European Southern Observatory (ESO) 1999

Online publication: September 2, 1999
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