NGC 4639
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| NGC 4639 | |
|---|---|
| NGC 4639 imaged by the Hubble Space Telescope [1] | |
| Observation data (J2000 epoch) | |
| Constellation | Virgo |
| Right ascension | 12h 42m 52.37814s[2] |
| Declination | +13° 15′ 26.7129″[2] |
| Heliocentric radial velocity | 989 km/s[3] |
| Distance | 72.02 ± 0.23 Mly (22.08 ± 0.07 Mpc)[3] |
| Group or cluster | Virgo Cluster |
| Apparent magnitude (V) | 12.2[4] |
| Characteristics | |
| Type | SAB(rs)bc[5] |
| Apparent size (V) | 2′.8 ×ばつ 1′.9[4] |
| Notable features | Seyfert type 1 |
| Other designations | |
| IRAS 12403+1331, LEDA 42741, MCG+02-32-189, NGC 4639, UGC 7884, VCC 1943,[6] PGC 42741[4] | |
NGC 4639 is a barred spiral galaxy located in the equatorial constellation of Virgo. It was discovered by German-born astronomer William Herschel on 12 April 1784. John L. E. Dreyer described it as "pretty bright, small, extended, mottled but not resolved, 12th magnitude star 1 arcmin to southeast".[7] This is a relatively nearby galaxy,[8] lying approximately 72 million light-years away from the Milky Way.[3] It is a companion to NGC 4654, and the two appear to have interacted roughly 500 million years ago.[9] NGC 4639 is a member of the Virgo Cluster.[10]
The morphological classification of this galaxy is SAB(rs)bc,[5] indicating a spiral galaxy with a weak bar (SAB), an incomplete ring around the bar (rs), and moderate to loosely-wound spiral arms (bc). NGC 4639 has a mildly active galactic nucleus of the Seyfert type 1; one of the weakest known. The compact central source has been detected by its X-ray emission, and is variable on timescales of months to years.[8] There is a supermassive black hole at the core[11] with an estimated mass of 7.9×ばつ106 M☉ .[12]
Supernovae
[edit ]Two supernovae have been observed in NGC 4639:
- SN 1990N (type Ia, mag. 15.5) was discovered by E. Thouvenot on 22 June 1990, two weeks before reaching peak brightness.[13] [14] [15] It was positioned 63.2′′ east and 1.8′′ south of the galaxy core.[13] The brightness and proximity of this supernova event has allowed it to be used as a standard candle.[15]
- SN 2018imf (type IIP, mag. 15.8) was discovered by Kōichi Itagaki on 14 November 2018.[16] [Note: while officially associated with NGC 4639, this supernova is actually much closer to the neighboring galaxy VCC 1931.]
References
[edit ]- ^ "Elegant spiral hides a hungry monster". Hubble Space Telescope. ESA. Retrieved 13 October 2015.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv:1804.09365 . Bibcode:2018A&A...616A...1G . doi:10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
- ^ a b c Tully, R. Brent; et al. (October 2013), "Cosmicflows-2: The Data", The Astronomical Journal, 146 (4): 25, arXiv:1307.7213 , Bibcode:2013AJ....146...86T, doi:10.1088/0004-6256/146/4/86, S2CID 118494842, 86
- ^ a b c "NASA/IPAC Extragalactic Database". Results for NGC 4639. Retrieved 2007年04月01日.
- ^ a b Graham, Alister W.; et al. (March 2019). "Expected intermediate-mass black holes in the Virgo cluster - II. Late-type galaxies". Monthly Notices of the Royal Astronomical Society. 484 (1): 814–831. arXiv:1811.03232 . Bibcode:2019MNRAS.484..814G. doi:10.1093/mnras/sty3068 . S2CID 119303249.
- ^ "NGC 4639". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2020年09月21日.
- ^ Seligman, Courtney. "New General Catalogue objects: NGC 4600 - 4649". cseligman.com. Retrieved 2020年09月19日.
- ^ a b Ho, Luis C.; et al. (November 1999). "X-Ray Properties of the Weak Seyfert 1 Nucleus in NGC 4639". The Astrophysical Journal. 525 (1): 168–175. arXiv:astro-ph/9905013 . Bibcode:1999ApJ...525..168H. doi:10.1086/307898. S2CID 14517224.
- ^ Vollmer, B. (February 2003). "NGC 4654: Gravitational interaction or ram pressure stripping?". Astronomy and Astrophysics. 398 (2): 525–539. arXiv:astro-ph/0211321 . Bibcode:2003A&A...398..525V. doi:10.1051/0004-6361:20021729. S2CID 7265130.
- ^ "Detailed Object Classifications". ned.ipac.caltech.edu. Retrieved 2017年08月29日.
- ^ Botkin-Kowacki, Eva (13 October 2015). "Spectacular Hubble photo: A bright galaxy holds a hidden secret". The Christian Science Monitor. Retrieved 14 October 2015.
- ^ Chiaraluce, E.; et al. (May 2019). "From radio-quiet to radio-silent: low-luminosity Seyfert radio cores". Monthly Notices of the Royal Astronomical Society. 485 (3): 3185–3202. arXiv:1902.10670 . Bibcode:2019MNRAS.485.3185C. doi:10.1093/mnras/stz595 . S2CID 119089306.
- ^ a b Maury, A.; et al. (June 1990). Green, D. W. E. (ed.). "Supernova 1990N in NGC 4639". IAU Circular. 5039: 1. Bibcode:1990IAUC.5039....1M.
- ^ "SN 1990N". Transient Name Server. IAU . Retrieved 6 December 2024.
- ^ a b Saha, A.; et al. (September 1997). "Cepheid Calibration of the Peak Brightness of Type Ia Supernovae. VIII. SN 1990N in NGC 4639". The Astrophysical Journal. 486 (1): 1–20. Bibcode:1997ApJ...486....1S. doi:10.1086/304507.
- ^ "SN 2018imf". Transient Name Server. IAU . Retrieved 6 December 2024.
External links
[edit ]- Media related to NGC 4639 at Wikimedia Commons
