IC 1101


IC 1101 is a supergiant elliptical galaxy at the center of the Abell 2029 galaxy cluster and is one of the largest known galaxies. Its halo extends about from its core, and it has a mass of about 100 trillion stars. The galaxy is located from Earth.

Characteristics

The galaxy is classified as a supergiant elliptical to lenticular and is the brightest galaxy in A2029. The galaxy's morphological type is debated due to it possibly being shaped like a flat disc but only visible from Earth at its broadest dimensions. However, most lenticulars have sizes ranging from.
IC 1101 is among the largest known galaxies, but there is debate in the astronomical literature about how to define the size of such a galaxy. Photographic plates of blue light from the galaxy yield an effective radius of. The galaxy has a very large halo of much lower intensity "diffuse light" extending to a radius of. The authors of the study identifying the halo conclude that IC 1101 is "possibly one of the largest and most luminous galaxies in the universe".
Like most large galaxies, IC 1101 is populated by a number of metal-rich stars, some of which are seven billion years older than the Sun, making it appear golden yellow in color. It has a bright radio source at the center, which is likely associated with an ultramassive black hole in the mass range of, one of the largest known black holes in the universe.

Discovery

The galaxy was discovered on 19 June 1790, by the British astronomer Frederick William Herschel I. It was catalogued in 1895 by John Louis Emil Dreyer as the 1,101st object of the Index Catalogue of Nebulae and Star Clusters. At its discovery, it was identified as a nebulous feature. Following Edwin Hubble's 1932 discovery that some of the "nebulous features" were actually independent galaxies, subsequent analysis of objects in the sky were conducted and IC 1101 was therefore found to be one of the independent galaxies.