NGC 4151

Source: Wikipedia, the free encyclopedia.
J2000 epoch)
ConstellationCanes Venatici
Right ascension12h 10m 32.6s[1]
Declination+39° 24′ 21″[1]
Redshift0.003262[2]
995 ± 3 km/s[1]
Distance15.8 ± 0.4 Mpc (51.5×10^6 ± 1.3×10^6 ly)[3]
Apparent magnitude (V)11.5[1]
Characteristics
Type(R')SAB(rs)ab,[1] Sy1[2]
Apparent size (V)6.4′ × 5.5′[1]
Other designations
UGC 7166,[1] PGC 38739[1]

NGC 4151 is an intermediate spiral Seyfert galaxy with weak inner ring structure located 15.8 megaparsecs (52 million light-years) from Earth[4] in the constellation Canes Venatici. The galaxy was first mentioned by William Herschel on March 17, 1787; it was one of the six Seyfert galaxies described in the paper [5] which defined the term. It is one of the nearest galaxies to Earth to contain an actively growing supermassive black hole.[6] The black hole would have a mass on the order of 2.5 million to 30 million solar masses.[7] It was speculated that the nucleus may host a binary black hole, with about 40 million and about 10 million solar masses respectively, orbiting with a 15.8-year period.[8] This is, however, still a matter of active debate.

Some astronomers nickname it the "

Eye of Sauron" from its appearance.[9]

One supernova has been observed in NGC 4151: SN 2018aoq (Type II, mag 14.4).[10]

X-ray source

NGC 4151. X-rays (blue), optical data (yellow), radio observation (red)
NGC 4151, by HST (WFC3).
Optical and ultraviolet images of the black hole in the center of NGC 4151
Astronomers using data from the European Space Agency's XMM-Newton satellite have found a long-sought X-ray signal from NGC 4151. When the black hole's X-ray source flares, its accretion disk reflects the emission about half an hour later.

X-ray emission from NGC 4151 was apparently first detected on December 24, 1970, with the X-ray observatory satellite

HEAO 1 detected an X-ray source of NGC 4151 at 1H 1210+393,[12] coincident with the optical position of the nucleus and outside the error box of Uhuru.[11]

To explain the X-ray emission two different possibilities have been proposed:[13]

  • radiation of material falling onto the central black hole (which was growing much more quickly about 25,000 years ago) was so bright that it stripped electrons away from the atoms in the gas in its path, and then electrons recombined with these ionized atoms
  • the energy released by material flowing into the black hole in an accretion disk created a vigorous outflow of gas from the surface of the disk, which directly heated gas in its path to X-ray emitting temperatures

See also

References

  1. ^ a b c d e f g h "Results for NGC 4151". NASA/IPAC Extragalactic Database. Retrieved 2007-03-27.
  2. ^ a b "NGC 4151". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-06-06.
  3. S2CID 220546047
    .
  4. ^ W. M. Keck Observatory (2014-11-26). "'Eye of Sauron' Provides New Way of Measuring Distances to Galaxies". W. M. Keck Observatory. Archived from the original on 2014-12-05. Retrieved 2014-11-27.
  5. doi:10.1086/144488
    .
  6. ^ "NGC 4151: An active black hole in the "Eye of Sauron"". Astronomy magazine. 2011-03-11. Archived from the original on 2019-03-29. Retrieved 2011-03-14.
  7. S2CID 235358825
    .
  8. S2CID 119257514
    .
  9. ^ Chandra X-ray Observatory (10 March 2011). "NGC 4151: An Active Black Hole in the "Eye of Sauron"". Chandra X-ray Center.
  10. ^ Transient Name Server entry for SN 2018aoq. Retrieved 5 January 2023.
  11. ^
    doi:10.1086/180713
    .
  12. doi:10.1086/190992
    .
  13. ^ Chandra X-Ray Observatory (2011-03-10). "The 'Eye of Sauron'". NASA. Archived from the original on 2011-04-23. Retrieved 2011-03-14.

External links

Wikimedia Commons has media related to NGC 4151.
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