NGC 2442 and NGC 2443

NGC 2442 / 2443
NGC 2442 / 2443
	NGC 2442 (upper spiral structure) and NGC 2443 (lower horizontal spiral arm)
Observation data (J2000 epoch)
Constellation	Volans
Right ascension	07h 36m 23.8s
Declination	−69° 31′ 51″
Redshift	1466 ± 5 km/s
Apparent magnitude (V)	11.2
Characteristics
Type	SAB(s)bc pec
Size	~160,000 ly (48.94 kpc) (estimated)
Apparent size (V)	5′.5 × 4′.9
Notable features	SW part is NGC 2442; while NE part is NGC 2443
Other designations
	PGC 21373

NGC 2442 and NGC 2443 are two parts of a single intermediate spiral galaxy, commonly known as the Meathook Galaxy or the Cobra and Mouse.^[3] It is about 50 million light-years away in the constellation Volans. It was discovered by Sir John Herschel on December 23, 1834 during his survey of southern skies with a 18.25 inch diameter reflecting telescope (his "20-foot telescope") from an observatory he set up in Cape Town, South Africa.^[4] Associated with this galaxy is HIPASS J0731-69, a cloud of gas devoid of any stars.^[5] It is likely that the cloud was torn loose from NGC 2442 by a companion.^[5]

When John Louis Emil Dreyer compiled the New General Catalogue of Nebulae and Clusters of Stars he used William Herschel's earlier observations that described two objects in a "double nebula", giving the northern most the designation NGC 2443 and the southernmost most the designation NGC 2442. Herschel's later observations noted that the two objects were actually a single large nebula.^[4]^[6]

Supernovae

Two, or perhaps three, supernovae have been observed in NGC 2442:

SN 1999ga (type II, mag. 18) was discovered by the Perth Astronomical Research Group on 19 November 1999.^[7]^[8]
SN 2015F (type Ia, mag. 16.8) was discovered by Libert "Berto" Monard on 9 March 2015.^[9]^[10] It reached magnitude 12.9, making it the brightest supernova of 2015.^[11]

Gaia16cfr, also known as AT 2016jbu,^[12]^[13] was a supernova imposter that occurred in NGC 2442 on 1 December 2016. It reached a Gaia apparent magnitude of 19.3 and absolute magnitude of about −12.^[14] However, a paper published in August 2022 suggested that this was a genuine, but strange, supernova.^[15]

References

^ NGC/IC Project Restoration Effortngcicproject.observers.org
^ ^a ^b ^c ^d ^e ^f ^g ^h "NASA/IPAC Extragalactic Database". Results for NGC 2442 / 2443. Retrieved 2023-02-08.
^ Chadwick, S; Cooper, I (11 December 2012). Imaging the Southern Sky. New York: Springer. p. 263. ISBN 978-1461447498.
^ ^a ^b Seligman, Courtney. "Celestial Atlas: NGC Objects: NGC 2400 - 2449". cseligman.com. Archived from the original on 9 September 2015. Retrieved 10 July 2015.
^ ^a ^b Ryder, S.D.; et al. (July 2001). "HIPASS Detection of an Intergalactic Gas Cloud in the NGC 2442 Group". The Astrophysical Journal. 555 (1): 232–239. arXiv:astro-ph/0103099. Bibcode:2001ApJ...555..232R. doi:10.1086/321453. S2CID 14455875.
^ NGC/IC Project Restoration Effortngcicproject.observers.org
^ Woodings, S.; Martin, R.; Williams, A.; Biggs, J.; Verveer, A. (1999). "Supernova 1999ga in NGC 2442". International Astronomical Union Circular (7316): 1. Bibcode:1999IAUC.7316....1W.
^ "SN 1999ga". Transient Name Server. IAU. Retrieved 9 December 2024.
^ Monard, L. A. G.; Fraser, M.; Smith, M.; Firth, R.; Dimitriadis, G.; Frohmaier, C.; Cartier, R.; Prajs, S.; Sullivan, M.; Anderson, J.; Maguire, K.; Inserra, C.; Smartt, S. J.; Smith, K. W.; Young, D.; Valenti, S.; Yaron, O.; Manulis, I. (2015). "Supernova 2015F in NGC 2442 = PSN J07361576-6930230". Central Bureau Electronic Telegrams (4081): 1. Bibcode:2015CBET.4081....1M.
^ "SN 2015F". Transient Name Server. IAU. Retrieved 9 December 2024.
^ Bishop, David. "Bright Supernovae - 2015". Rochester Astronomy. Retrieved 9 December 2024.
^ "AT 2016jbu". Transient Name Server. IAU. Retrieved 31 August 2024.
^ Fox, Derek (4 January 2017). "PESSTO classification and characterisation of AT 2016jbu / Gaia16cfr". The Astronomer's Telegram. Retrieved 31 August 2024.
^ Kilpatrick, Charles D.; Foley, Ryan J.; Drout, Maria R.; Pan, Yen-Chen; Panther, Fiona H.; Coulter, David A.; Filippenko, Alexei V.; Marion, G. Howard; Piro, Anthony L.; Rest, Armin; Seitenzahl, Ivo R.; Strampelli, Giovanni; Wang, Xi E. (2018). "Connecting the progenitors, pre-explosion variability and giant outbursts of luminous blue variables with Gaia16cfr". Monthly Notices of the Royal Astronomical Society. 473 (4): 4805. arXiv:1706.09962. Bibcode:2018MNRAS.473.4805K. doi:10.1093/mnras/stx2675.
^ Brennan, S. J.; Elias-Rosa, N.; Fraser, M.; Van Dyk, S. D.; Lyman, J. D. (2022). "The impostor revealed: SN 2016jbu was a terminal explosion". Astronomy and Astrophysics. 664: L18. arXiv:2206.06365. Bibcode:2022A&A...664L..18B. doi:10.1051/0004-6361/202244262.