NGC 612

NGC 612 is a lenticular galaxy in the constellation of Sculptor located approximately 388 million light-years from Earth. It is a type II Seyfert galaxy and thus has an active galactic nucleus.[1][3] NGC 612 has been identified as an extremely rare example of a non-elliptical radio galaxy, hosting one of the nearest powerful FR-II radio sources.[5][6]

NGC 612
Hubble Space Telescope image of NGC 612
Observation data (J2000 epoch)
ConstellationSculptor
Right ascension01h 33m 57.74s[1]
Declination−36° 29′ 35.7″[1]
Redshift0.02977 ± 0.00010[1]
Heliocentric radial velocity8925 ± 29 km/s[1]
Distance388×106 ly (119.33 ± 8.36 Mpc)[1]
Apparent magnitude (V)13[2]
Characteristics
TypeS0
Size~122.43 kpc (diameter)[1]
Apparent size (V)1.5 × 0.9 arcmin[3]
Notable featuresRare example of a non-elliptical radio galaxy
Other designations
MCG -06-04-046, PGC 5827[4]

Observation history

The object was discovered by British astronomer John Herschel on 29 November, 1837.[2] John Louis Emil Dreyer, compiler of the first New General Catalogue of Nebulae and Clusters of Stars, described NGC 612 as a "faint, very small, round, 12th magnitude star to the west."[2]

Physical characteristics
Radio emission around NGC 612

NGC 612 has a fairly well-developed luminous disc seen almost edge-on and features a strong dust ring.[5] The galaxy is surrounded by an enormous disc of cool neutral hydrogen gas with a mass of 1.8×109 M☉ distributed in a 140 kpc wide structure along the galactic disc and dust lane of NGC 612. The majority of the gas is relatively settled in regular rotation with a velocity of 8900 km/s. A faint bridge, spanning 400 kpc, exists between NGC 612 and the gas-rich barred spiral galaxy NGC 619, indicating that an interaction between both galaxies occurred at some point. Current or past interaction, such as a merger event, is currently the most likely trigger of NGC 612's radio source.[6]

The galaxy has an unusually young star population, with populations throughout the galactic disc having an age of ~0.04 - 0.1 Gyr.[6]

NGC 612 is one[7] of 5 (as of 2020) known lenticular galaxies that show large-scale radio emissions. Both spiral galaxies and lenticular galaxies rarely host large scale radio emissions. It is not understood why these type of galaxies are so rare.[8]

See also

References
  1. "NGC 612 NASA/IPAC Extragalactic Database Results". ned.ipac.caltech.edu. Retrieved 2018-10-31.
  2. "New General Catalog Objects: NGC 600 - 649". cseligman.com. Retrieved 2018-10-31.
  3. "Revised NGC Data for NGC 612". spider.seds.org. Retrieved 2018-10-31.
  4. "NGC 612". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-19.
  5. Véron-Cetty, M. P.; Véron, P. (2001). "Are all radio galaxies genuine ellipticals?". Astronomy & Astrophysics. 375 (3): 791–796. Bibcode:2001A&A...375..791V. doi:10.1051/0004-6361:20010902. ISSN 0004-6361.
  6. Emonts, B. H. C.; Morganti, R.; Oosterloo, T. A.; Holt, J.; Tadhunter, C. N.; van der Hulst, J. M.; Ojha, R.; Sadler, E. M. (2008). "Enormous disc of cool gas surrounding the nearby powerful radio galaxy NGC 612 (PKS 0131−36)". Monthly Notices of the Royal Astronomical Society. 387 (1): 197–208. arXiv:0805.3371. Bibcode:2008MNRAS.387..197E. doi:10.1111/j.1365-2966.2008.13142.x. ISSN 0035-8711. S2CID 7916786.
  7. Ekers, R. D.; Goss, W. M.; Kotanyi, C. G.; Skellern, D. J. (1978-10-01). "NGC 612-A Radio Galaxy with a Disk". Astronomy and Astrophysics. 69: L21. ISSN 0004-6361.
  8. Duchesne, S. W.; Johnston-Hollitt, M. (2019-04-01). "The remnant radio galaxy associated with NGC 1534". Publications of the Astronomical Society of Australia. 36: e016. arXiv:1806.09255. doi:10.1017/pasa.2018.26. ISSN 1323-3580.
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