[8] Almost a decade and a half later, in 1978, astronomer Alan Dressler analyzed 12 very rich clusters of galaxies, among them Abell 2029, where IC 1101 is located.

[9] The following year, he released a paper dedicated solely to IC 1101 and its related dynamics and properties, revealing a rising velocity dispersion profile.

[11] During 1985, a team of astronomers obtained the spectra of the gas inside several galaxy clusters known to be luminous at X-ray wavelengths, including Abell 2029.

[20][21] That same year, an analysis of the galaxy's inner regions using Hubble Space Telescope images found a huge yet diffuse galactic core, accompanied with mass estimates of the central supermassive black hole.

[24][25] 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.

[3] Like most large galaxies, IC 1101 is populated by a number of metal-rich stars, some of which are as much as seven billion years older than the Sun, making it appear golden yellow in color.

It has a very bright radio source at the center, which is likely associated with an ultramassive black hole in the mass range of 40–100 billion M☉ measured using core dynamical models,[5] or alternatively at 50-70 billion M☉ using gas accretion rate and growth modelling,[26] which would make IC 1101's black hole one of the most massive known to date.

[28] For many years it was suggested that IC 1101 was at the center of a massive cooling flow within the Abell 2029 cluster,[27] but later observations dismissed this.

The galaxy has a very large halo of much lower intensity "diffuse light" extending to a radius of 600 kpc (2 million ly).

[30][verification needed] 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".

This view has been stated in several other papers as well, but this figure was based on an earlier assumed distance of 262 megaparsecs (855 million light-years).

Redman in 1936)[33][b] has been utilized by the RC3 in the B-band, with a measured major axis (log 2a+1) of 1.08 (equivalent to 72.10 arcseconds),[3] translating to a diameter of 123.65 kiloparsecs (403,000 ly).

[1] Another calculation by the Two Micron All-Sky Survey using the "total" aperture at the K-band yields a much larger size of 169.61 kiloparsecs (553,000 ly).

A measurement made in 2005 by the Arecibo Observatory using the 21-cm hydrogen emission line yields a redshift of z = 0.021,[36] and hence a distance of 97.67 ± 6.84 megaparsecs (318.6 ± 22.3 million light-years).

[10] The depleted core and other characteristics of IC 1101 such as the halo component and its structure at moderate distances from the center suggest that the galaxy underwent numerous galactic mergers and interactions, perhaps as much as 10 or even more.