Observational Signature of Tidal Disruption of a Star by a Massive Black Hole

Abstract

We have modeled the time-variable profiles of the Halpha emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a million solar mass black hole. We find that the line profiles at these very early stages of the evolution of the post-disruption debris do not resemble the double peaked profiles expected from a rotating disk since the debris has not yet settled into such a stable structure. The predicted line profiles vary on fairly short time scales (of order hours to days). As a result of the uneven distribution of the debris and the existence of a ``tidal tail'' (the stream of returning debris), the line profiles depend sensitively on the orientation of the tail relative to the line of sight. Given the illuminating UV/X-ray light curve, we also model the Halpha light curve from the debris.

arXiv comment2 pages, 1 figure, to appear in the proceedings of "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", IAU 222, eds. Th. Storchi Bergmann, L.C. Ho, and H.R. Schmitt