Richard Saxton

ESA XMM-Newton

I work for XMM and have worked on AGN since the days when fitting
a single power-law to the X-ray spectrum was perfectly acceptable.
Recently I have become interested in normal galaxies which flare
in X-rays for a few months and then return to anonymity. The
favoured explanation is that a star in the centre of the  galaxy,
wanders into the gravitational pull of a quiet central massive
black hole (~10^6 solar masses), supposedly present in 50% of all
galaxies. The star then suffers a painful death as lumps are
ripped off at each perigee passage, forming an accretion disk
which powers an AGN-type activity for a few months until the bulk
of the  matter is consumed. We have found a few of these in the
XMM slew survey and are following them up at the moment with
optical and further X-ray observations.