Program: GN-2013A-Q-37

Intermediate-mass black holes (IMBH, ~10^2-10^5 solar mass) have been long sought after because they are predicted to exist in several important astrophysical processes such as the collapse of massive population III stars and tidal stripping of merging satellite dwarf galaxies. They are also leading candidates for gravitational wave emission. The strongest IMBH candidates are hyperluminous off-nuclear X-ray sources (HLX) with Lx > 10^{41} erg/s. However, there are only about a dozen marginal candidates found around this limit, and only ESO 243-49 HLX-1 reaches a luminosity of 10^{42} erg/s. We have identified a new HLX candidate with an estimated X-ray luminosity of 10^{43} erg/s using the distance derived from the uncertain photometric redshift (0.4) of the host galaxy. We propose a Gemini spectroscopic observation to measure the spectroscopic redshift and nuclear activity of the host galaxy to confirm our discovery of the most luminous and the most distant IMBH known and to provide strong evidence for IMBH existence.