Unexpectedly Little Black-hole Monsters Rapidly Suck up Surrounding Matter

Using the Subaru Telescope, researchers at the Special Astrophysical Observatory in Russia and Kyoto University in Japan have found evidence that enigmatic objects in nearby galaxies – called ultra-luminous X-ray sources (ULXs) – exhibit strong outflows that are created as matter falls onto their black holes at unexpectedly high rates. The strong outflows suggest that the black holes in these ULXs must be much smaller than expected. Curiously, these objects appear to be “cousins” of SS 433, one of the most exotic objects in our own Milky Way Galaxy. The team’s observations help shed light on the nature of ULXs, and impact our understanding of how supermassive black holes in galactic centers are formed and how matter rapidly falls onto those black holes.

Multi-color optical image around the ULX
Figure. Multi-color optical image around the ULX "X-1" (indicated by the arrow) in the dwarf galaxy Holmberg II, located in the direction of the constellation Ursa Major, at a distance of 11 million light-years. The image size corresponds to 1,100 × 900 light-years at the galaxy. The red color represents spectral line emission from hydrogen atoms. (Credit: Special Astrophysical Observatory/ Hubble Space Telescope) Original Size (576KB)

This work has been published online in Nature Physics on 2015 June 1 (Fabrika et al. 2015, “Supercritical Accretion Discs in Ultraluminous X-ray Sources and SS 433”, 10.1038/nphys3348).