Discovery of a red supergiant donor star in SN2010da/NGC 300 ULX-1

M. Heida, R. M. Lau, B. Davies +7

SN2010da/NGC 300 ULX-1 was first detected as a supernova impostor in May 2010 and was recently discovered to be a pulsating ultraluminous X-ray source. In this letter, we present V…