NGC 4555

NGC 4555
NGC 4555
	NGC 4555 in X-ray and optical spectra
Observation data (J2000 epoch)
Constellation	Coma Berenices
Right ascension	12h 35m 41.2s
Declination	+26° 31′ 23″
Redshift	6683 ± 24 km/s
Apparent magnitude (V)	13.1
Characteristics
Type	E
Apparent size (V)	1.9′ × 1.6′
Other designations
	IC 3545, UGC 7762, PGC 41975

Last updated June 29, 2023

NGC 4555 is a solitary elliptical galaxy about 40,000 parsecs (125,000 light-years) across, and about 310 million light-years distant. Observations by the Chandra X-ray Observatory have shown it to be surrounded by a halo of hot gas about 120,000 parsecs across. The hot gas has a temperature of around 10,000,000 kelvin. The galaxy is one of the few elliptical galaxies proven to have significant amounts of dark matter. Large amounts of dark matter are necessary to prevent the gas from escaping the galaxy; the visible mass clearly is not large enough to hold such an extensive gas halo. The dark matter halo is estimated to have 10 times the mass of the stars in the galaxy.

NGC 4555 is important because of its isolation. Most elliptical galaxies are found in the cores of groups and clusters of galaxies, and almost all those for which dark matter estimates are available located in the centers of these larger systems. In these circumstances it is impossible to know whether the dark matter is associated with the galaxy or the surrounding cluster. NGC 4555, as a field galaxy, is not part of any group or cluster, and therefore provides strong evidence that dark matter can be associated with individual ellipticals.

Despite being isolated, NGC 4555 is part of the Coma Supercluster.^[2]

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<span class="mw-page-title-main">NGC 4494</span> Galaxy in the constellation Coma Berenices

NGC 4494 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 4494 is about 60,000 light years across. It was discovered by William Herschel in 1785.

NGC 4473 is an elliptical galaxy located about 50 million light-years away in the constellation of Coma Berenices. It was discovered by astronomer William Herschel on April 8, 1784. NGC 4473 has an inclination of about 71°. NGC 4473 is a member of a chain of galaxies called Markarian's Chain which is part of the larger Virgo Cluster of galaxies.

ESO 444-46 is a class E4 supergiant elliptical galaxy; the dominant and brightest member of the Abell 3558 galaxy cluster around 640 million light-years away in the constellation Centaurus. It lies within the core of the massive Shapley Supercluster, one of the closest neighboring superclusters. It is one of the largest galaxies in the local universe, and possibly contains one of the most massive black holes known. The black hole's mass is very uncertain, with estimates ranging from as low as 501 million M_☉, to as high as 77.6 billion M_☉.

NGC 720 is an elliptical galaxy located in the constellation Cetus. It is located at a distance of circa 80 million light years from Earth, which, given its apparent dimensions, means that NGC 720 is about 110,000 light years across. It was discovered by William Herschel on October 3, 1785. The galaxy is included in the Herschel 400 Catalogue. It lies about three and a half degrees south and slightly east from zeta Ceti.

NGC 4636 is an elliptical galaxy located in the constellation Virgo. It is a member of the NGC 4753 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It is located at a distance of about 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4636 is about 105,000 light years across.

IC 1459 is an elliptical galaxy located in the constellation Grus. It is located at a distance of circa 85 million light-years from Earth, which, given its apparent dimensions, means that IC 1459 is about 130,000 light-years across. It was discovered by Edward Emerson Barnard in 1892.

NGC 4278 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4278 is about 65,000 light years across. It was discovered by William Herschel on March 13, 1785. NGC 4278 is part of the Herschel 400 Catalogue and can be found about one and 3/4 of a degree northwest of Gamma Comae Berenices even with a small telescope.

NGC 4066 is an elliptical galaxy located 340 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 27, 1785. NGC 4066 is a member of the NGC 4065 Group.

NGC 4070 is an elliptical galaxy located 340 million light-years away in the constellation Coma Berenices. NGC 4070 was discovered by astronomer William Herschel on April 27, 1785. It was rediscovered by John Herschel on April 29, 1832 and was listed as NGC 4059. The galaxy is a member of the NGC 4065 Group.

NGC 4089 is an elliptical galaxy located 340 million light-years away in the constellation Coma Berenices. NGC 4089 was discovered by astronomer Heinrich d'Arrest on May 4, 1864 and is a member of the NGC 4065 Group.

NGC 4095 is an elliptical galaxy located 330 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 26, 1785. NGC 4095 is a member of the NGC 4065 Group and is a LINER.

The NGC 4065 Group is a group of galaxies located about 330 Mly (100 Mpc) in the constellation Coma Berenices. The group's brightest member is NGC 4065 and located in the Coma Supercluster.

NGC 4084 is an elliptical galaxy located 315 million light-years away in the constellation Coma Berenices. NGC 4084 was discovered by astronomer Heinrich d'Arrest on April 26, 1865. NGC 4084 is an isolated member of the Coma Supercluster and is classified as a LINER galaxy.

NGC 3937 is an elliptical or a lenticular galaxy located about 310 million light-years away in the constellation Leo. It was discovered by astronomer William Herschel on April 27, 1785 and is classified as a radio galaxy.

References

1 2 3 4 5 6 7 8 "NASA/IPAC Extragalactic Database". Results for NGC 4555. Retrieved 2006-11-16.
↑ Gregory, S. A.; Thompson, L. A. (June 15, 1978). "The Coma/A1367 supercluster and its environs". The Astrophysical Journal. 222: 784–799. Bibcode:1978ApJ...222..784G. doi:10.1086/156198. ISSN 0004-637X.

External links

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[ned-1] 1 2 3 4 5 6 7 8 "NASA/IPAC Extragalactic Database". Results for NGC 4555. Retrieved 2006-11-16.

[2] Gregory, S. A.; Thompson, L. A. (June 15, 1978). "The Coma/A1367 supercluster and its environs". The Astrophysical Journal. 222: 784–799. Bibcode:1978ApJ...222..784G. doi:10.1086/156198. ISSN 0004-637X.

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