Markarian 177

Markarian 177
James Webb Space Telescope MIRI image with the LBV marked
Observation data (J2000.01 epoch)
Constellation	Ursa Major2
Right ascension	11h 33m 23.474s1
Declination	+55° 04′ 20.10″1
Redshift	0.0080881
Distance	90,000,000 ly (28 Mpc)2 h−1 0.678
Apparent magnitude (V)	15.71
Notable features	SDSS J113323.97+550415.8 — Ejected supermassive black hole3
Other designations
Markarian 177, MKR 177, MKN 177, MRK 177, Mark 177, 2MASX J11332348+5504204,4 SDSS J113323.47+550420.6,1 PGC 35678,1 LEDA 35678,4 UGCA 2391

Markarian 177 is a blue compact⁵ dwarf galaxy located 90,000,000 ly (28 Mpc) away, at the constellation of Ursa Major, in the bowl of the Big Dipper asterism.² It was discovered by the astronomer Benjamin Markarian.

Markarian 177 is a peculiar galaxy⁵ that is receding from us at a rate of 2425 km/s. It has a visual apparent size of 0.41×0.34 arcmin.¹

Near the galaxy, at over 2,600 ly (800 pc) 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 (12 pc) 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.²³⁶