NGC 4800 is an isolated[6]spiral galaxy in the constellation Canes Venatici, located at a distance of 95 megalight-years from the Milky Way.[3] It was discovered by William Herschel on April 1, 1788.[7] The morphological classification of this galaxy is SA(rs)b,[5] indicating a spiral galaxy with no visual bar at the nucleus (SA), an incomplete ring structure (rs), and moderately-tightly wound spiral arms (b). The galactic plane is inclined to the line of sight by an angle of 43°, and the long axis is oriented along a position angle of 25°.[8] There is a weak bar structure at the nucleus that is visible in the infrared.[6]
The galaxy has a low-luminosity active galactic nucleus with an HII region at the core.[5] The circumnuclear zone contains a double ring structure of "ultra-compact nuclear rings"; the inner ring has a radius of 30 pc and the outer ring's radius is about 130 pc.[6] The upper limit on the mass of the central supermassive black hole is estimated as 2.0×107M☉, or 20 million times the mass of the Sun.[9]
^Ho, Luis C.; et al. (February 2002). "An Efficient Strategy to Select Targets for Gasdynamical Measurements of Black Hole Masses Using the Hubble Space Telescope". The Publications of the Astronomical Society of the Pacific. 114 (792): 137–143. arXiv:astro-ph/0110671. Bibcode:2002PASP..114..137H. doi:10.1086/338546. S2CID17982236.