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arXiv · 0903.0164

Tidal Capture by a Black Hole and Flares in Galactic Centres

A. Gomboc·A. Cadez·M. Calvani·U. Kostic
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Abstract

We present the telltale signature of the tidal capture and disruption of an object by a massive black hole in a galactic centre. As a result of the interaction with the black hole's strong gravitational field, the object's light curve can flare-up with characteristic time of the order of 100 sec \times (M_{bh} / 10^6 M_{Solar}). Our simulations show that general relativity plays a crucial role in the late stages of the encounter in two ways: (i) due to the precession of perihelion, tidal disruption is more severe, and (ii) light bending and aberration of light produce and enhance flares seen by a distant observer. We present our results for the case of a tidally disrupted Solar-type star. We also discuss the two strongest flares that have been observed at the Galactic centre. Although the first was observed in X-rays and the second in infra-red, they have almost identical light curves and we find it interesting that it is possible to fit the infra-red flare with a rather simple model of the tidally disrupted comet-like or planetary object. We discuss the model and possible scenarios how such an event can occur.

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A. Gomboc, A. Cadez, M. Calvani, U. Kostic. 2009-03-01. Tidal Capture by a Black Hole and Flares in Galactic Centres. https://doi.org/10.1007/978-3-540-74713-0_32

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