Astronomy:NGC 718

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NGC 718
NGC 718 imaged by SDSS
Observation data (J2000 epoch)
ConstellationPisces
Right ascension 01h 53m 13.2826s[1]
Declination+04° 11′ 44.805″[1]
Redshift0.005781±0.0000300[1]
Helio radial velocity1,733±9 km/s[1]
Distance69.7 ± 5.0 Mly (21.38 ± 1.54 Mpc)[1]
Group or clusterNGC 676 group
Apparent magnitude (V)12.59[1]
Characteristics
TypeSAB(s)a[1]
Size~99,000 ly (30.35 kpc) (estimated)[1]
Apparent size (V)2.3′ × 2.0′[1]
Other designations
IRAS 01506+0357, UGC 1356, MCG+01-05-041, PGC 6993[1]

NGC 718 is a intermediate spiral galaxy in the constellation of Pisces. Its velocity with respect to the cosmic microwave background is 1,450±22 km/s, which corresponds to a Hubble distance of 69.7 ± 5.0 Mly (21.38 ± 1.54 Mpc).[1] Additionally, one non-redshift measurement gives a similar distance of 69.80 Mly (21.400 Mpc).[2] It was discovered by German-British astronomer William Herschel on 13 December 1784.[3][4]

NGC 718 has a possible active galactic nucleus, i.e. it has a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars.[5][6]

A star-forming disk has been detected around the core of NGC 718. The size of its semi-major axis is estimated at 1,100 ly (330 pc).[7]

Supermassive black hole

Based on measurements of the near-infrared K-band luminosity of the galaxy's bulge, NGC 718 has a supermassive black hole with a mass of 1×107.5M☉ (32 million solar masses).[8]

NGC 676 group

NGC 718 is a member of a small group of three galaxies known as the NGC 676 group. The other two galaxies are NGC 676 and NGC 693 (fr).[9]

Intermediate-luminosity red transient

One intermediate-luminosity red transient (ILRT) has been observed in NGC 718:

  • AT 2019udc (Type ILRT, mag. 18.813) was discovered by the Distance Less Than 40 Mpc Survey (DLT40) on 4 November 2019.[10] This object had initially been classified as a luminous blue variable.[11][12]

See also

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 "Results for object NGC 0718". NASA and Caltech. https://ned.ipac.caltech.edu/byname?objname=NGC+0718. 
  2. ↑ "Distance Results for NGC 0718". NASA. https://ned.ipac.caltech.edu/cgi-bin/nDistance?name=NGC+0718. 
  3. ↑ Herschel, William (1786). "Catalogue of One Thousand New Nebulae and Clusters of Stars". Philosophical Transactions of the Royal Society of London 76: 457–499. doi:10.1098/rstl.1786.0027. Bibcode: 1786RSPT...76..457H. https://zenodo.org/record/1432282/files/article.pdf. 
  4. ↑ Seligman, Courtney. "New General Catalogue Objects: NGC 718". https://cseligman.com/text/atlas/ngc7.htm#718. 
  5. ↑ Asmus, D.; Greenwell, C. L.; Gandhi, P.; Boorman, P. G.; Aird, J.; Alexander, D. M.; Assef, R. J.; Baldi, R. D. et al. (2020). "Local AGN survey (LASr): I. Galaxy sample, infrared colour selection, and predictions for AGN within 100 MPC". Monthly Notices of the Royal Astronomical Society 494 (2): 1784. doi:10.1093/mnras/staa766. Bibcode: 2020MNRAS.494.1784A. 
  6. ↑ "NGC 718". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+718. 
  7. ↑ Comerón, S.; Knapen, J. H.; Beckman, J. E.; Laurikainen, E.; Salo, H.; Martínez-Valpuesta, I.; Buta, R. J. (2010). "AINUR: Atlas of Images of NUclear Rings". Monthly Notices of the Royal Astronomical Society 402 (4): 2462. doi:10.1111/j.1365-2966.2009.16057.x. Bibcode: 2010MNRAS.402.2462C. 
  8. ↑ Dong, X. Y.; De Robertis, M. M. (2006). "Low-Luminosity Active Galaxies and Their Central Black Holes". The Astronomical Journal 131 (3): 1236. doi:10.1086/499334. Bibcode: 2006AJ....131.1236D. 
  9. ↑ Mahtessian, A. P. (1998). "Groups of galaxies. III. Some empirical characteristics". Astrophysics 41 (3): 308–321. doi:10.1007/BF03036100. Bibcode: 1998Ap.....41..308M. 
  10. ↑ Valerin, G. et al. (2025). "A study in scarlet: I. Photometric properties of a sample of intermediate-luminosity red transients". Astronomy and Astrophysics 695. doi:10.1051/0004-6361/202451733. Bibcode: 2025A&A...695A..42V. 
  11. ↑ "AT 2019udc". IAU. https://www.wis-tns.org/object/2019udc. 
  12. ↑ Siebert, M. R.; Dimitriadis, G.; Kilpatrick, C. D.; Foley, R. J.; Nunez, R.; McKinnon, K.; Guhathakurta, P. (2019). "Spectroscopic Classification of AT2019udc with the Lick Shane telescope". The Astronomer's Telegram 13263: 1. Bibcode: 2019ATel13263....1S. 

Coordinates: Sky map 01h 53m 13.2826s, +04° 11′ 44.805″



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