History

On 11 April 1785 William Herschel discovered total 72 nebulae using his 18.7-inch reflecting telescope, most of them he classified as faint nebulae (class II) and very faint nebulae (class II). Among those discovered nebulae were: NGC 4864, 4874, 4889, 4908, 4911, 4921, 4923 and 4927. John Herschel verified his father's observations on 13 April 1831 and added four more nebulae: NGC 4853, 4869, 4894 and 4898. ^{[364, 466]}

Heinrich d'Arrest conducted multiple observations from May 1863 through April 1885 using the 11-inch refractor at Copenhagen Observatory to verify the nebulae discovered by the two Herschels. The following 17 nebulae were added to Dreyer's «New General Catalogue»: NGC 4848, 4850, 4851, 4854, 4858, 4860, 4865, 4867, 4871, 4872, 4873, 4881, 4886, 4895, 4906, 4907 and 4919. D'Arrest was the first to recognize the Coma assemblage of galaxies as a cluster and wrote: «The nebulae are incredibly numerous and dense and despite being faint, they have a diversity one cannot imagine a priori. Sometimes, in the most favorable moments, I had the very definite impression that the nebulae, often only a few arcseconds in diameter, are intermingled with larger, roung, oblong, star-shaped or cometary ones, like oysters packed together in a barrel.» ^{[313, 364]}

In May 1885, Guillaume Bigourdan observed this galaxy cluster with the 12.4-inch refractor at the Paris Observatory and discovered additional nebulae: NGC 4875, 4876, 4883, and 4896 were added by Dreyer in his «New General Catalogue» in 1888. Observations from April 1891 later appeared in Dreyer's two «Index Catalogue»: IC 839, IC 4051, and IC 4045. ^{[313, 314, 315, 364]}

Using the 18-inch refractor at the Strasbourg Observatory Hermann Kobold discovered in April/May 1895 and 1896 many more nebulae which were added in 2010 by Dreyer to his «Second Index Catalogue»: IC 3943, 3946, 3947, 3949, 3955, 3957, 3959, 3960, 3963, 3964, 3968, 3973, 3976, 3998, 4011, 4012, 4021, 4026, 4030, 4033, 4040, 4041, 4042, and 4044. ^{[315, 364]}

Physical Properties

NGC 4889 is a giant elliptical galaxy, about two and a half times larger than the Milky Way. In the centre of the featureless looking galaxy NGC 4899 lies a supermassive black hole with a mass 21 billion times greater than the Sun. Its event horizon is estimated with a diameter of approximately 130 billion kilometres, circa 15 times the diameter of Neptune’s orbit from the Sun. For comparison: The black hole at the centre of our galaxy is thought to be 4 million times more massive than the Sun with an event horizon just one fifth the orbit of Mercury. The black hole in the centre NGC 4889 of is currently inactive. It has stopped sucking in material and new stars are actually forming and orbiting around it. ^[261]

The two galaxies NGC 4874 and NGC 4889 dominate the gravitational centre of the Coma Cluster of galaxies (Abell 1656, ACO 1656). It is located circa 300 million light-years and according to Simbad it contains more than 3000 galaxies, most of them elliptical. ^[145] In the following table all the galaxies with NGC/IC numbers as shown in the 1° close-up of the finder chart are listed.