Large-amplitude X-ray outbursts from galactic nuclei: A systematic survey using ROSAT archival data

摘要: In recent years, luminous X-ray outbursts with variability amplitudes as high ≈400 have been serendipitously detected from a small number of active and inactive galaxies. These may result the tidal disruptions stars by supermassive black holes, well accretion disk instabilities. order to place first reliable constraints on rate such in universe test stellar disruption hypothesis, we performed systematic complete survey for them cross-correlating ROSAT All-Sky Survey (RASS) pointed Position Sensitive Proportional Counter data. We five galaxies that were outburst during RASS, three which show no signs nuclear activity; these objects had reported individually previous studies. After making reasonable corrections complicated selection effects, conclude large-amplitude local is ≈9.1 × 10-6 galaxy-1 yr-1. This consistent predicted events When only two are considered, find ≈8.5 10-4 tighter rates, additional must be detected.