NGC 4639

NGC 4639
A Hubble Space Telescope (HST) image of NGC 4639.[1]
Observation data (J2000 epoch)
ConstellationVirgo
Right ascension12h 42m 52.37814s[2]
Declination+13° 15′ 26.7129″[2]
Heliocentric 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]
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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]

  1. ^ Cite error: The named reference HST was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Tully2013 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference ned was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Graham2019 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference cseligman was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Ho1999 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Vollmer2003 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference NED2 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Botkin-Kowacki2015 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Chiaraluce2019 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Saha1997 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Maury1990 was invoked but never defined (see the help page).
  15. ^ Transient Name Server entry for SN 2018imf. Retrieved 23 March 2023.