IC 4397
IC 4397 is a spiral galaxy in the constellation of Boötes. Its velocity with respect to the cosmic microwave background is, which corresponds to a Hubble distance of. It was discovered by French astronomer Guillaume Bigourdan on 23 June 1889.
IC 4397 has an active galactic nucleus, i.e. it has a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. It is a Seyfert II galaxy, i.e. it has a quasar-like nucleus with very high surface brightness, whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable. The nucleus also shines brightly in the ultraviolet. IC 4397 is listed in the Markarian catalogue as Mrk1510.