Astronomy:NGC 4639

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Short description: Galaxy in the constellation Virgo

Coordinates: Sky map 12h 42m 52.4s, +13° 15′ 27″

NGC 4639
Elegant spiral hides a hungry monster.jpg
A Hubble Space Telescope (HST) image of NGC 4639.[1]
Observation data (J2000 epoch)
ConstellationVirgo
Right ascension 12h 42m 52.37814s[2]
Declination+13° 15′ 26.7129″[2]
Helio radial velocity989 km/s[3]
Distance72.02 ± 0.23 Mly (22.08 ± 0.07 Mpc)[3]
Group or clusterVirgo Cluster
Apparent magnitude (V)12.2[4]
Characteristics
TypeSAB(rs)bc[5]
Apparent size (V)2′.8 × 1′.9[4]
Notable featuresSeyfert 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 April 12, 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 7.9×106 M☉.[12]

Two supernovae have been observed in NGC 4639. The classical Type Ia Supernova SN 1990N was discovered in this galaxy on June 22, 1990, two weeks before reaching peak brightness.[13] It was positioned 63.2″ east and 1.8″ south of the galaxy core.[14] The brightness and proximity of this supernova event has allowed it to be used as a standard candle.[13] SN 2018imf (type IIP, mag. 15.7) was discovered on 14 November, 2018.[15]

References

  1. ↑ "Elegant spiral hides a hungry monster". ESA. http://www.spacetelescope.org/images/potw1541a/. 
  2. ↑ 2.0 2.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 Tully, R. Brent et al. (October 2013), "Cosmicflows-2: The Data", The Astronomical Journal 146 (4): 25, doi:10.1088/0004-6256/146/4/86, 86, Bibcode: 2013AJ....146...86T 
  4. ↑ 4.0 4.1 4.2 "NASA/IPAC Extragalactic Database". Results for NGC 4639. http://nedwww.ipac.caltech.edu/. 
  5. ↑ 5.0 5.1 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. doi:10.1093/mnras/sty3068. Bibcode: 2019MNRAS.484..814G. 
  6. ↑ "NGC 4639". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+4639. 
  7. ↑ Seligman, Courtney. "New General Catalogue objects: NGC 4600 - 4649". https://cseligman.com/text/atlas/ngc46.htm#4639. 
  8. ↑ 8.0 8.1 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. doi:10.1086/307898. Bibcode: 1999ApJ...525..168H. 
  9. ↑ Vollmer, B. (February 2003). "NGC 4654: Gravitational interaction or ram pressure stripping?". Astronomy and Astrophysics 398 (2): 525–539. doi:10.1051/0004-6361:20021729. Bibcode: 2003A&A...398..525V. 
  10. ↑ "Detailed Object Classifications". https://ned.ipac.caltech.edu/cgi-bin/NEDatt?objname=NGC+4639. 
  11. ↑ Botkin-Kowacki, Eva (13 October 2015). "Spectacular Hubble photo: A bright galaxy holds a hidden secret". The Christian Science Monitor. http://www.csmonitor.com/Science/2015/1013/Spectacular-Hubble-photo-A-bright-galaxy-holds-a-hidden-secret. 
  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. doi:10.1093/mnras/stz595. Bibcode: 2019MNRAS.485.3185C. 
  13. ↑ 13.0 13.1 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. doi:10.1086/304507. Bibcode: 1997ApJ...486....1S. 
  14. ↑ Maury, A. et al. (June 1990). Green, D. W. E.. ed. "Supernova 1990N in NGC 4639". IAU Circular 5039: 1. Bibcode: 1990IAUC.5039....1M. 
  15. ↑ Transient Name Server entry for SN 2018imf. Retrieved 23 March 2023.

External links



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