UV/optical detections of candidate tidal disruption events by GALEX and CFHTLS

作者：Gezari S^*; Basa S; Martin D C; Bazin G; Forster K; Milliard B; Halpern J P; Friedman P G; Morrissey P; Neff S G; Schiminovich D; Seibert M; Small T; Wyder T K

来源：Astrophysical Journal, 2008, 676(2): 944-969.

DOI：10.1086/529008

• galaxies : g nuclei
• ultraviolet : galaxies
• X-rays : galaxies

We present two luminous UV/optical flares from the nuclei of apparently inactive early-type galaxies at z = 0.37 and 0.33 that have the radiative properties of a flare from the tidal disruption of a star. In this paper we report the second candidate tidal disruption event discovery in the UV by the GALEX Deep Imaging Survey and present simultaneous optical light curves from the CFHTLS Deep Imaging Survey for both UV flares. The first few months of the UV/optical light curves are well fitted with the canonical t(-5/3) power-law decay predicted for emission from the fallback of debris from a tidally disrupted star. Chandra ACIS X-ray observations during the flares detect soft X-ray sources with T(bb) = (2-5) x 10(5) K or Gamma > 3 and place limits on hard X-ray emission from an underlying AGN down to L(X)(2-10 keV) less than or similar to 10(41) ergs s(-1). Blackbody fits to the UV/optical spectral energy distributions of the flares indicate peak flare luminosities of greater than or similar to 10(44) - 10(45) ergs s(-1). The temperature, luminosity, and light curves of both flares are in excellent agreement with emission from a tidally disrupted main-sequence star onto a central black hole of several times 10(7) M(circle dot). The observed detection rate of our search over similar to 2.9 deg(2) of GALEX Deep Imaging Survey data spanning from 2003 to 2007 is consistent with tidal disruption rates calculated from dynamical models, and we use these models to make predictions for the detection rates of the next generation of optical synoptic surveys.

• 出版日期2008-4-1
• 单位中国地震局