Tidal Capture by a Black Hole and Flares in Galactic Centres
  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.
