NGC 2617
Galaxy in the constellation Hydra
From Wikipedia, the free encyclopedia
NGC 2617 is a Seyfert galaxy in the equatorial constellation of Hydra. It was discovered on February 12, 1885, by French astronomer Édouard Stephan.[7][8] In 1888, Danish astronomer J. L. E. Dreyer described it as "extremely faint, very small, 2 very faint stars involved".[9] It is located at an estimated distance of 202 million light years.[2] In the infrared, the galaxy has an angular size of 0.693 by 0.652 arcminutes.[5]
| NGC 2617 | |
|---|---|
legacy surveys image of NGC 2617 (right) and MCG-01-22-027 | |
| Observation data (J2000 epoch) | |
| Constellation | Hydra |
| Right ascension | 08h 35m 38.798s[1] |
| Declination | −04° 05′ 17.90″[1] |
| Heliocentric radial velocity | 4,287 km/s[2] |
| Distance | 201.8 Mly (61.86 Mpc)h−1 0.73[2] |
| Apparent magnitude (V) | 12.66±0.20[3] |
| Apparent magnitude (B) | 14.10±0.30[3] |
| Characteristics | |
| Type | Sc[4][3] |
| Apparent size (V) | 0.693′ × 0.652′[5] (infrared) |
| Other designations | |
| IRAS F08331-0354, 2MASX J08353877-0405172, NGC 2617, MCG −01–22–026[6] | |
This is an almost face-on spiral galaxy with a morphological classification of Sc,[4] indicating a spiral galaxy (S) with loosely wound spiral arms (c). In 1992, NGC 2617 was shown to be an extragalactic source of X-ray emission,[10] and in 1996 it was identified as a Seyfert 1.8 galaxy by E. C. Moran and associates.[11] A radio counterpart was found in 1998.[12]
During April 2013, a dramatic outburst was discovered at the core of NGC 2617,[13] and the spectral type was found to have changed to a Seyfert 1. An increase in X-ray emission was observed, followed by an increase in ultraviolet and then infrared luminosity.[4] This event can be modeled by X-ray radiation heating the accretion disk orbiting a supermassive black hole (SMBH) at the center of the galaxy. This was followed by emission at longer wavelengths from the heated disk.[4] An increase in luminosity between 2010 and 2012 may have cleared away dust in the inner part of the disk prior to the outburst, allowing a clearer view and changing the Seyfert type of the galaxy.[14] The SMBH has an estimated mass of 30.9+11.8
−8.5 million M☉.[3]
Additional outbursts were observed from 2016 to 2018, in between deep minima.[15]