Discovery of multiple ultra-luminous X-ray sources in the galaxy KUG 0214-057

Abstract

We report the serendipitous discovery of several unresolved X-ray sources lying in the prominent spiral arms of the galaxy KUG 0214-057 in XMM-Newton observations. The location of these X-ray sources strongly suggests that at least three, and possibly four, of these may be physically related to the galaxy. The luminosity of each of these sources at the distance of KUG 0214-057 is >5 × 10³⁹~erg s^-1 (0.3-10 keV), making each a strong candidate ultraluminous X-ray source (ULX). Using the ULXs objects as a metric implies that this relatively low-mass galaxy may be experiencing rather intense starburst activity. The serendipitous discovery of these ULXs objects suggests that such objects are not a negligible component of the overall extragalactic X-ray source population.