NGC 4993

NGC 4993
NGC 4993 and GRB 170817A afterglow as taken by Hubble Space Telescope[1]
Observation data (J2000 epoch)
ConstellationHydra
Right ascension13h 09m 47.7s[2]
Declination−23° 23′ 02″[2]
Redshift0.009727[2]
Heliocentric radial velocity2916 km/s[2]
Distance44.1 Mpc (144 Mly)[2]
Group or clusterNGC 4993 Group[3]
Apparent magnitude (V)13.32[2]
Characteristics
Type(R')SAB0^-(rs)[2]
Size~55,000 ly (17 kpc) (estimated)[2]
Apparent size (V)1.3 x 1.1[2]
Notable featuresHost of neutron star merger detected as gravitational wave GW170817 and gamma-ray burst GRB 170817A
Other designations
NGC 4994, ESO 508-18, AM 1307-230, MCG -4-31-39, PGC 45657, WH III 766[4]
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NGC 4993 starmap near ψ Hydrae, near galaxies of NGC 4968, NGC 4970, NGC 5042, IC 4180, IC 4197

NGC 4993 (also catalogued as NGC 4994 in the New General Catalogue) is a lenticular galaxy[5] located about 140 million light-years away[2] in the constellation Hydra.[6] It was discovered on 26 March 1789[7] by William Herschel[6][7] and is a member of the NGC 4993 Group.[3]

NGC 4993 was the site of GW170817, a collision of two neutron stars, the first astronomical event detected in both electromagnetic and gravitational radiation, a discovery given the Breakthrough of the Year award for 2017 by the journal Science.[8][9] Detecting a gravitational wave event associated with the gamma-ray burst provided direct confirmation that binary neutron star collisions produce short gamma-ray bursts.[10]

  1. ^ Cite error: The named reference NASA-20171016a was invoked but never defined (see the help page).
  2. ^ a b c d e f g h i j "NASA/IPAC Extragalactic Database". Results for NGC 4993. Retrieved 3 June 2018.
  3. ^ a b Hjorth, Jens; Levan, Andrew J.; Tanvir, Nial R.; Lyman, Joe D.; Wojtak, Radosław; Schrøder, Sophie L.; Mandel, Ilya; Gall, Christa; Bruun, Sofie H. (16 October 2017). "The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817". The Astrophysical Journal. 848 (2): L31. arXiv:1710.05856. Bibcode:2017ApJ...848L..31H. doi:10.3847/2041-8213/aa9110. hdl:2381/41880. S2CID 51812508.
  4. ^ Staff (2017). "Galaxy NGC 4993 - Galaxy in Hydra Constellation". dso-browser.com. Archived from the original on 16 September 2017. Retrieved 30 September 2017.
  5. ^ Cite error: The named reference :2 was invoked but never defined (see the help page).
  6. ^ a b "NGC 4993". Deep Sky Observer's Companion. Retrieved 28 August 2017.
  7. ^ a b "New General Catalog Objects: NGC 4950 - 4999". cseligman.com. Retrieved 5 June 2018.
  8. ^ "Breakthrough of the year 2017". Science | AAAS. 22 December 2017.
  9. ^ Cho, Adrian (2017). "Cosmic convergence". Science. 358 (6370): 1520–1521. Bibcode:2017Sci...358.1520C. doi:10.1126/science.358.6370.1520. PMID 29269456.
  10. ^ Overbye, Dennis (16 October 2017). "LIGO Detects Fierce Collision of Neutron Stars for the First Time". The New York Times. Retrieved 16 October 2017.