Summary
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) | |
| Constellation | Sculptor |
| Right ascension | 01h 33m 57.74s[1] |
| Declination | −36° 29′ 35.7″[1] |
| Redshift | 0.02977 ± 0.00010[1] |
| Heliocentric radial velocity | 8925 ± 29 km/s[1] |
| Distance | 388×106 ly (119.33 ± 8.36 Mpc)[1] |
| Apparent magnitude (V) | 13[2] |
| Characteristics | |
| Type | S0 |
| Size | ~122.43 kpc (diameter)[1] |
| Apparent size (V) | 1.5 × 0.9 arcmin[3] |
| Notable features | Rare example of a non-elliptical radio galaxy |
| Other designations | |
| MCG -06-04-046, PGC 5827[4] | |
Observation history edit
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 "faint, very small, round, 12th magnitude star to the west."[2]
Physical characteristics edit
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 edit
- NGC 4151 - another example of a non-elliptical radio galaxy
- List of galaxies
References edit
- ^ a b c d e f g "NGC 612 NASA/IPAC Extragalactic Database Results". ned.ipac.caltech.edu. Retrieved 2018-10-31.
- ^ a b c "New General Catalog Objects: NGC 600 - 649". cseligman.com. Retrieved 2018-10-31.
- ^ a b "Revised NGC Data for NGC 612". spider.seds.org. Retrieved 2018-10-31.
- ^ "NGC 612". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-19.
- ^ a b 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.
- ^ a b c 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.
- ^ 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.
- ^ 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.