Astronomy:NGC 2787

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Short description: Galaxy in the constellation Ursa Major
NGC 2787
NGC 2787.jpg
NGC 2787 as observed by the Hubble Space Telescope (HST).
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension 09h 19m 18.60430s[1]
Declination+69° 12′ 11.6429″[1]
Helio radial velocity627.3±13.2 km/s[2]
Distance24.17 ± 0.46 Mly (7.41 ± 0.14 Mpc)[3]
Apparent magnitude (V)11.79[4]
Apparent magnitude (B)12.92[4]
Absolute magnitude (B)−18.84[5]
Characteristics
TypeSB(r)0+[6]
Mass/Light ratio50[5] M☉/L☉
Size5.5 kpc[5]
Apparent size (V)2′.530 × 1′.518[7] (NIR)
Notable featuresBarred lenticular; LINER
Other designations
PGC 26341, UGC 4914[8]

NGC 2787 is a barred lenticular galaxy approximately 24[3] million light-years away in the northern constellation of Ursa Major. It was discovered on December 3, 1788 by German-born astronomer William Herschel. J. L. E. Dreyer described it as, "bright, pretty large, a little extended 90°, much brighter middle, mottled but not resolved, very small (faint) star involved to the southeast".[9] The visible galaxy has an angular size of 2.5 × 1.5 arcminutes[7] or 3.24 × 1.81 arcminutes[10] and an apparent visual magnitude of 11.8.[4]

This galaxy is small and isolated[5] with a morphological classification of SB(r)0+,[6] which indicates a barred spiral (SB) with a ring around the bar (r). Being a lenticular galaxy, it has the large halo of an elliptical galaxy. The disk is inclined at an angle of 58°±3° to the line of sight from the Earth, with the major axis aligned along a position angle of 110°±3°.[5] The galaxy has an unusually high mass-to-light ratio, much greater than for a typical spiral galaxy.[5] The distribution of the galaxy's neutral hydrogen forms a clumpy ring with a radius of 10.3 kpc, double that of the visible galaxy, with a mass of 5.5×108 M☉.[5] This ring appears misaligned with the central disk.[11]

NGC 2787 contains a low-ionization nuclear emission-line region (LINER) at its core, which is a type of region that is characterized by its spectral line emission from weakly ionized atoms.[12] LINERs are very common within lenticular galaxies, with approximately one-fifth of nearby lenticular galaxies containing LINERs.[13] The supermassive black hole at the center has a mass of 4.1+0.4
−0.5×107 M☉.[14] The central region of the galaxy contains dust rings that are tilted with respect to the disk, which may be the result of an encounter with another galaxy.[11]

References

  1. ↑ 1.0 1.1 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.
  2. ↑ van den Bosch, Remco C. E. et al. (May 2015). "Hunting for Supermassive Black Holes in Nearby Galaxies With the Hobby-Eberly Telescope". The Astrophysical Journal Supplement Series 218 (1): 13. doi:10.1088/0067-0049/218/1/10. 10. Bibcode: 2015ApJS..218...10V. 
  3. ↑ 3.0 3.1 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 Véron-Cetty, M.-P.; Véron, P. (2010). "A catalogue of quasars and active nuclei". Astronomy & Astrophysics. 13th 518. doi:10.1051/0004-6361/201014188. A10. Bibcode: 2010A&A...518A..10V. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Shostak, G. S. (March 1987). "The distribution of HI in the lenticular galaxy NGC 2787". Astronomy and Astrophysics 175: 4–8. Bibcode: 1987A&A...175....4S. 
  6. ↑ 6.0 6.1 Erwin, Peter; Debattista, Victor P. (June 2013). "Peanuts at an angle: detecting and measuring the three-dimensional structure of bars in moderately inclined galaxies". Monthly Notices of the Royal Astronomical Society 431 (4): 3060–3086. doi:10.1093/mnras/stt385. Bibcode: 2013MNRAS.431.3060E. 
  7. ↑ 7.0 7.1 Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W. et al. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal 131 (2): 1163–1183. doi:10.1086/498708. ISSN 0004-6256. Bibcode: 2006AJ....131.1163S. https://ui.adsabs.harvard.edu/abs/2006AJ....131.1163S/abstract. 
  8. ↑ "NASA/IPAC Extragalactic Database". Results for NGC 2787. http://nedwww.ipac.caltech.edu/. Retrieved 2006-12-13. 
  9. ↑ Seligman, Courtney. "NGC Objects: NGC 2750 - 2799". Celestial Atlas. https://cseligman.com/text/atlas/ngc27a.htm#2787. Retrieved 2020-09-09. 
  10. ↑ "NGC 2787 - Lenticular Galaxy in Ursa Major". TheSkyLive.com. https://theskylive.com/sky/deepsky/ngc2787-object. 
  11. ↑ 11.0 11.1 Erwin, Peter et al. (November 2003). "When Is a Bulge Not a Bulge? Inner Disks Masquerading as Bulges in NGC 2787 and NGC 3945". The Astrophysical Journal 597 (2): 929–947. doi:10.1086/378189. Bibcode: 2003ApJ...597..929E. 
  12. ↑ Ho, L. C. et al. (1997). "A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies". Astrophysical Journal Supplement 112 (2): 315–390. doi:10.1086/313041. Bibcode: 1997ApJS..112..315H. 
  13. ↑ Ho, L. C. et al. (1997). "A Search for "Dwarf" Seyfert Nuclei. V. Demographics of Nuclear Activity in Nearby Galaxies". Astrophysical Journal 487 (2): 568–578. doi:10.1086/304638. Bibcode: 1997ApJ...487..568H. 
  14. ↑ Graham, Alister W. (November 2008). "Populating the Galaxy Velocity Dispersion - Supermassive Black Hole Mass Diagram: A Catalogue of (Mbh, σ) Values". Publications of the Astronomical Society of Australia 25 (4): 167–175. doi:10.1071/AS08013. Bibcode: 2008PASA...25..167G. 

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