Markarian 177

Markarian 177 is a blue compact dwarf galaxy located 90000000 ly away, at the constellation of Ursa Major, in the bowl of the Big Dipper asterism. It was discovered by the astronomer Benjamin Markarian.

Markarian 177 is a peculiar galaxy that is receding from us at a rate of 2425 km/s. It has a visual apparent size of 0.41×0.34 arcmin.

SDSS1133
Near the galaxy, at over 2600 ly from it, is a luminous X-ray source named SDSS J113323.97+550415.8 (SDSS1133), in orbit around Markarian 177. The source has been stable for some decades from the 1950s through the 2000s, and the emission region is some 40 ly wide. It may be an ejected supermassive black hole from a galaxy that interacted with Markarian 177.

Alternative explanations for the X-ray source include it possibly being a luminous blue variable star that has recently undergone a supernova in the early 2000s, where for the previous five decades it had been in continuous eruption.