Type

Supermassive

Location

in the constellation Lynx

Distance

76 million light-years (23 megaparsecs)

Mass

9 million to 36 million times the mass of the Sun

Size

From smaller than Mercury's orbit to as large as Venus' orbit

Discovery Methods

• Measuring the motions of stars

NGC 2778

NGC 2778 is one of the more distant galaxies for which a central black hole has been detected. It is classified as a dwarf elliptical galaxy, which means that it's smaller and fainter than the Milky Way. Even with the sharp view from Hubble Space Telescope, the measurements for this galaxy are not as good as for brighter galaxies. As a result, the mass of its black hole can’t be determined as precisely -- it probably lies somewhere between 9 million and 36 million solar masses. At this mass, NGC 2778 has one of the smallest black holes relative to the size of the galaxy, making it one of the most important galaxies for understanding the relationship between black holes and their hosts.

Most elliptical galaxies have only a small net rotation -- their stars all orbit the center of the galaxy in randrom directions, like a swarm of gnats, with roughly equal numbers going clockwise and counterclockwise. NGC 2778, however, shows substantial rotation. Stars on one side of the galaxy's center are moving toward us compared to stars on the other side. Astronomers aren't sure yet why NGC 2778 (and others like it) behaves this way, but it might have something to do with how NGC 2778 formed.

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This document was last modified: November 19, 2009.