What is galaxy m54?

Galaxy M54 is a dwarf elliptical galaxy located in the Sagittarius constellation. It is estimated to be approximately 90,000 light-years away from Earth and has a diameter of about 7,200 light-years. M54 was first discovered in 1778 by French astronomer Charles Messier and was later listed in his catalog of astronomical objects as Messier 54. It is the third brightest globular cluster in the Milky Way galaxy and contains more than a hundred thousand stars. M54 is believed to have been originally part of the Sagittarius dwarf galaxy, which merged with the Milky Way galaxy billions of years ago. It is also known for containing two black holes, one of which is believed to be a possible intermediate-mass black hole.