  The starburst galaxy M82 at a distance of 12 million light years, is the host
of an unusually bright $2.4-16\times 10^{40}$ erg/s X-ray point source, which
is best explained by an accreting black hole $10^{2}$ to $10^4$ times more
massive than the Sun. Though the strongest candidate for a so called
intermediate mass black hole, the only support stems from the observed
luminosity and the 0.05-0.1 Hz quasi periodicity in its signal. Interestingly,
the $7-12 $Myr old star cluster MGG-11 which has been associated with the X-ray
source is sufficiently dense that an intermediate mass black hole could have
been produced in the cluster core via collision runaway. The recently
discovered $62.0\pm 2.5$ day periodicity in the X-ray source X-1 further
supports the hypothesis that this source is powered by a black hole several
hundred times more massive than the Sun. We perform detailed binary evolution
simulations with an accreting compact object of $10-5000 \msun $ and find that
the X-ray luminosity, the age of the cluster, the observed quasi periodic
oscillations and the now observed orbital period are explained best by a black
hole of $200-5000 \msun $ that accretes material from a $22-25\msun$ giant
companion in a state of Roche-lobe contact. Interestingly such a companion star
is consistent with the expectation based on the tidal capture in a young and
dense star cluster like MGG-11, making the picture self consistent.
