NGC 6251

NGC 6251
Hubble image of the heart of the active galaxy NGC 6251
Observation data (J2000 epoch)
Constellation	Ursa Minor
Right ascension	16^h 32^m 31.9700^s[1]
Declination	+82° 32′ 16.400″[1]
Redshift	0.02471[1]
Distance	340 million light-years[2]
Apparent magnitude (V)	14.3[3]
Characteristics
Type	E[1]
Apparent size (V)	1.82´X1.55´
Other designations
NGC 6251, UGC 10501, LEDA 58472, 6C 1636+8239, QSO B1637+826

NGC 6251 is an active supergiant elliptical radio galaxy in the constellation Ursa Minor, and is more than 340 million light-years away from Earth. The galaxy has a Seyfert 2 active galactic nucleus,^[3] and is one of the most extreme examples of a Seyfert galaxy. This galaxy may be associated with gamma-ray source 3EG J1621+8203, which has high-energy gamma-ray emission.^[3] It is also noted for its one-sided radio jet—one of the brightest known—discovered in 1977.^[4] The supermassive black hole at the core has a mass of (5.9±2.0)×10⁸ M_☉.^[5]

References

1. "NASA/IPAC Extragalactic Database". Results for NGC 6251. Retrieved 2006-10-26.
2. "Distance and Length". Online-Unit-Converter.com. Archived from the original on 2010-03-30. Retrieved 2010-03-29.
3. SIMBAD
4. Perley, R. A.; Bridle, A. H.; Willis, A. G. (1984). "High-resolution VLA Observations of the Radio Jet in NGC 6251". Astrophysical Journal Supplement Series. 54: 291–334. Bibcode:1984ApJS...54..291P. doi:10.1086/190931.
5. Graham, Alister W. (November 2008), "Populating the Galaxy Velocity Dispersion - Supermassive Black Hole Mass Diagram: A Catalogue of (Mbh, σ) Values", Publications of the Astronomical Society of Australia, 25 (4): 167–175, arXiv:0807.2549, Bibcode:2008PASA...25..167G, doi:10.1071/AS08013, S2CID 89905.

External links

• Media related to NGC 6251 at Wikimedia Commons
• www.jb.man.ac.uk/atlas/
• Wikisky image of NGC 6251
• Hubble Finds a Bare Black Hole Pouring Out Light (Probing the heart of the active galaxy NGC 6251—September 10, 1997)