February 29, 2012 | 5 Something unusual has been spotted lurking
around several galaxies’ central black holes. Astronomers think
it may be limiting the growth of the black holes – and stars
elsewhere in the galaxies, too. Astronomers studying nearby
galaxies have found a new type of outflow called an ultra-fast
outflow, or UFO. An international team of astronomers led by
Francesco Tombesi from the University of Maryland and NASA’s
Goddard Space Flight Centre in Maryland, US, carried out the
work. They published their findings in Monthly Notices of the
Royal Astronomical Society yesterday. Astronomers have known for
years that the more massive the black hole lying at the centre
of a galaxy, the more stars they could expect to find in that
galaxy’s ‘bulge’ – a large, roughly spherical region packed with
stars. But they thought it was a little odd that the two were
linked. A black hole – though often portrayed as an all-
consuming cosmic vacuum cleaner – only really affects the space
close to it and on the whole