Astronomy:NGC 4725

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Short description: Galaxy in the constellation Coma Berenices
NGC 4725
NGC 4725.jpg
A mid-infrared image of NGC 4725 taken by the Spitzer Space Telescope (SST)
Observation data (J2000 epoch)
ConstellationComa Berenices[1]
Right ascension 12h 50m 26.56929s[2]
Declination+25° 30′ 02.7376″[2]
Helio radial velocity1,206±3 km/s[3]
Distance40.1 ± 6.2 Mly (12.3 ± 1.9 Mpc)[4]
Apparent magnitude (V)10.1[3]
Characteristics
TypeSAB(r)ab pec[5] or Sb/SB(r)II[6]
Apparent size (V)9′.77 × 6′.76[7]
Other designations
IRAS 12480+2547, NGC 4725, UGC 7989, PGC 43451[7][8]

NGC 4725 is an intermediate barred spiral galaxy with a prominent ring structure,[9] located in the northern constellation of Coma Berenices near the north galactic pole.[10] It was discovered by German-born astronomer William Herschel on April 6, 1785.[11] The galaxy lies at a distance of approximately 40 megalight-years[4] from the Milky Way. NGC 4725 is the brightest member of the Coma I Group[12] of the Coma-Sculptor Cloud, although it is relatively isolated from the other members of this group.[6] This galaxy is strongly disturbed and is interacting with neighboring spiral galaxy NGC 4747, with its spiral arms showing indications of warping. The pair have an angular separation of 24′, which corresponds to a projected linear separation of 370 kly.[5] A tidal plume extends from NGC 4747 toward NGC 4725.[10]

NGC 4725 is a suspected type 2 Seyfert galaxy with a supermassive black hole at the core.[13] The morphological classification of this galaxy is SAB(r)ab pec,[5] indicating a peculiar, weakly-barred spiral galaxy (SAB) with a complete ring surrounding the bar (r) and somewhat tightly-wound spiral arms (ab). It is actually double-barred, a feature found among about a third of all barred spirals.[14] The galactic plane is inclined by approximately 46° to the line of sight from the Earth.[6]

Ring structure

The ring structure of the galaxy is a region of star formation. It is offset from the galactic center and displays non-circular motion.[15] There is a compact radio source positioned approximately 6.2 kly from the nucleus of NGC 4725. Since there is no optical counterpart at that position, this may be a star forming region that is heavily obscured by dust.[9]

Supernova

Multiple supernova candidate events have been detected in this galaxy:

  • SN 1940B was detected on a photograph taken May 5, 1940, about 2.5′ northeast of the galactic core.[16] The light curve indicates this was a type II supernova.[17]
  • SN 1969H was discovered on 17 June 1969, with a magnitude of 15.[18]
  • Candidate SN 1987E was detected April 24, 1987 with a magnitude of 15.65.[19] A follow-up study failed to detect this event, so it may have been the result of gravitational lensing.[20]
  • SN 1999gs was detected on December 28, 1999 with a magnitude of 19.3. It was positioned 3″ west and 105″ south of the nucleus of NGC 4725.[21]
  • On automated images taken July 5, 2016, a magnitude 17.0 transient source was discovered at an angular separation of 324″ from the galactic nucleus. Designated ASASSN-16gu (AT 2016cyu), this was most likely a supernova event. It had an estimated absolute visual magnitude of –13.6.[22]

References

  1. ↑ Sinnott, R. W., ed (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN 978-0-933346-51-2. 
  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 "NASA/IPAC Extragalactic Database". Results for NGC 4725. http://nedwww.ipac.caltech.edu/. 
  4. ↑ 4.0 4.1 Jensen, Joseph B.; Tonry, John L.; Barris, Brian J.; Thompson, Rodger I. et al. (February 2003). "Measuring Distances and Probing the Unresolved Stellar Populations of Galaxies Using Infrared Surface Brightness Fluctuations". Astrophysical Journal 583 (2): 712–726. doi:10.1086/345430. Bibcode: 2003ApJ...583..712J. 
  5. ↑ 5.0 5.1 5.2 Wevers, B. M. H. R. et al. (November 1984). "Neutral hydrogen observations of the interacting galaxies NGC 4725 and NGC 4747". Astronomy and Astrophysics 140: 125–140. Bibcode: 1984A&A...140..125W. 
  6. ↑ 6.0 6.1 6.2 Gibson, Brad K. et al. (February 1999). "The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XVII. The Cepheid Distance to NGC 4725". The Astrophysical Journal 512 (1): 48–64. doi:10.1086/306762. Bibcode: 1999ApJ...512...48G. 
  7. ↑ 7.0 7.1 Paturel, G. et al. (December 2003). "HYPERLEDA. I. Identification and designation of galaxies". Astronomy and Astrophysics 412: 45–55. doi:10.1051/0004-6361:20031411. Bibcode: 2003A&A...412...45P. 
  8. ↑ "NGC 4725". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+4725. 
  9. ↑ 9.0 9.1 Murphy, E. J. et al. (July 2018). "A New Detection of Extragalactic Anomalous Microwave Emission in a Compact, Optically Faint Region of NGC 4725". The Astrophysical Journal 862 (1): 7. doi:10.3847/1538-4357/aac5f5. 20. Bibcode: 2018ApJ...862...20M. 
  10. ↑ 10.0 10.1 Barber, C. R.; Warwick, R. S. (March 1994). "The spectrum of the extragalactic X-ray background below 3 keV". Monthly Notices of the Royal Astronomical Society 267 (2): 270–282. doi:10.1093/mnras/267.2.270. Bibcode: 1994MNRAS.267..270B. 
  11. ↑ Seligman, Courtney. "NGC Objects: NGC 4700 - 4749". https://cseligman.com/text/atlas/ngc47.htm#4725. 
  12. ↑ Gregory, S.A.; Thompson, L. A. (1977). "The Coma I Galaxy Cloud" (in en). The Astrophysical Journal 213: 345–350. doi:10.1086/155160. ISSN 0004-637X. Bibcode: 1977ApJ...213..345G. 
  13. ↑ 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. 
  14. ↑ de Lorenzo-Cáceres, A.; Falcón-Barroso, J.; Vazdekis, A.; Martínez-Valpuesta, I. (September 2008). "Stellar Kinematics in Double-Barred Galaxies: The σ-Hollows". The Astrophysical Journal Letters 684 (2): L83. doi:10.1086/592145. Bibcode: 2008ApJ...684L..83D. 
  15. ↑ Buta, R. (March 1988). "The Structure and Dynamics of Ringed Galaxies. V. The Kinematics of NGC 1512, NGC 3351, NGC 4725, and NGC 4736". Astrophysical Journal Supplement 66: 233. doi:10.1086/191255. Bibcode: 1988ApJS...66..233B. 
  16. ↑ Minkowski, R. (June 1940). "Spectra of the Supernova in NGC 4725". Publications of the Astronomical Society of the Pacific 52 (307): 206. doi:10.1086/125169. Bibcode: 1940PASP...52..206M. 
  17. ↑ Minkowski, R. (1964). "Supernovae and Supernova Remnants". Annual Review of Astronomy and Astrophysics 2: 247. doi:10.1146/annurev.aa.02.090164.001335. Bibcode: 1964ARA&A...2..247M. 
  18. ↑ Transient Name Server entry for SN 1969H. Retrieved 25 March 2023.
  19. ↑ Rosa, M.; Koishikawa, M. (April 1987). Green, D. W. E.. ed. "Supernova 1987E in NGC 4725". IAU Circular 4374 (2): 2. Bibcode: 1987IAUC.4374....2R. 
  20. ↑ Filippenko, A. V. (May 1987). Green, D. W. E.. ed. "No Supernova in NGC 4725". IAU Circular 4385 (2): 2. Bibcode: 1987IAUC.4385....2F. 
  21. ↑ Li, W. D. (January 2000). Green, D. W. E.. ed. "Supernova 1999gs in NGC 4725". IAU Circular 7345 (2): 2. Bibcode: 2000IAUC.7345....2L. 
  22. ↑ Brimacombe, J. et al. (July 2016). "ASASSN-16gu: Discovery of A Probable Supernova in NGC 4725". The Astronomer's Telegram 9211: 1. Bibcode: 2016ATel.9211....1B. 

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