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  • 21 Aug, 2019

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SN 1990N
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". This is a relatively nearby galaxy, lying approximately 72 million light-years away from the Milky Way. It is a companion to NGC 4654, and the two appear to have interacted roughly 500 million years ago. NGC 4639 is a member of the Virgo Cluster.

The morphological classification of this galaxy is SAB(rs)bc, 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. There is a supermassive black hole at the core with an estimated mass of 7.9×10 M☉.

Supernovae

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. It was positioned 63.2″ east and 1.8″ south of the galaxy core. The brightness and proximity of this supernova event has allowed it to be used as a standard candle.
  • SN 2018imf (type IIP, mag. 15.8) was discovered by Kōichi Itagaki on 14 November 2018. [Note: while officially associated with NGC 4639, this supernova is actually much closer to the neighboring galaxy VCC 1931.]

References

  1. ^ "Elegant spiral hides a hungry monster". Hubble Space Telescope. ESA. Retrieved 13 October 2015.
  2. ^ 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.
  3. ^ 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
  4. ^ "NASA/IPAC Extragalactic Database". Results for NGC 4639. Retrieved 2007-04-01.
  5. ^ 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.
  6. ^ "NGC 4639". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-09-21.
  7. ^ Seligman, Courtney. "New General Catalogue objects: NGC 4600 - 4649". cseligman.com. Retrieved 2020-09-19.
  8. ^ 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.
  9. ^ 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.
  10. ^ "Detailed Object Classifications". ned.ipac.caltech.edu. Retrieved 2017-08-29.
  11. ^ Botkin-Kowacki, Eva (13 October 2015). "Spectacular Hubble photo: A bright galaxy holds a hidden secret". The Christian Science Monitor. Retrieved 14 October 2015.
  12. ^ 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.
  13. ^ Maury, A.; et al. (June 1990). Green, D. W. E. (ed.). "Supernova 1990N in NGC 4639". IAU Circular. 5039: 1. Bibcode:1990IAUC.5039....1M.
  14. ^ "SN 1990N". Transient Name Server. IAU. Retrieved 6 December 2024.
  15. ^ 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.
  16. ^ "SN 2018imf". Transient Name Server. IAU. Retrieved 6 December 2024.
  • Media related to NGC 4639 at Wikimedia Commons
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