Star cluster surrounds wayward black hole in cannibal galaxy ESO 243-49 (labelled)
Date: 14 February 2012
Satellite: Hubble Space Telescope
Depicts: ESO 243-49, ESO 243-49 HLX-1
Copyright: NASA, ESA, and S. Farrell (University of Sydney, Australia and University of Leicester, UK)
This spectacular edge-on galaxy, called ESO 243-49, is home to an intermediate-mass black hole that may have been purloined from a cannibalised dwarf galaxy. The black hole, with an estimated mass of 50 million Suns, lies above the galactic plane. This is an unlikely place for such a massive back hole to exist, unless it belonged to a small galaxy that was gravitationally torn apart by ESO 243-49.
The circle identifies a unique X-ray source that pinpoints the black hole. The X-rays are believed to be radiation from a hot accretion disc around the black hole. The blue light not only comes from a hot accretion disc, but also from a cluster of hot young stars that formed around the black hole. The galaxy is 290 million light-years from Earth. Hubble can't resolve the stars individually because the suspected cluster is too far away. Their presence is inferred from the colour and brightness of the light coming from the black hole's location.
