1ES 1101-232 is an active galactic nucleus of a distant galaxy known as a blazar.

[3] In 1989, Remillard and colleagues linked the X-ray source with a visual object and established that the object was surrounded by a large elliptical galaxy.

They also discovered that the object (and galaxy) were more distant, with a redshift of 0.186.

[5] Between 2004 and 2005, 1ES 1101-232 showed gamma-ray emission which was detected by the High Energy Stereoscopic System of Atmospheric Cherenkov Telescope.

Astronomers observed it for 43 hours, which they studied the blazar for its inner jets and the extragalactic background light.