Yet another galaxy identification for an ultraluminous X-ray source
Palazzi, E.; Masetti, N.; Foschini, L.; Ho, L. C.; Dadina, M.; Di Cocco, G.; Malaguti, G.
Italy, Switzerland, United States
Abstract
We report on the identification of the optical and infrared counterparts of the ultraluminous X-ray source (ULX) XMMU J121214.5+131248 (NGC4168-ULX1). The optical spectrum yields a redshift of z=0.217, which implies that the ULX is not associated with the nearby galaxy NGC 4168, but rather with a background object. Optical spectral line ratios and the spectral energy distribution constructed from the available data indicate that the source is likely a starburst nucleus.
Based on observations collected at the Bologna Astronomical Observatory in Loiano, Italy, and at the Astronomical Observatory of Asiago, Italy.