Astronomy:NGC 5557
| {{{name}}} | |
|---|---|
| NGC 5557 SDSS image of NGC 5557 | |
| Observation data (J2000 epoch) | |
| Constellation | Boötes |
| Right ascension | 14h 18m 25.708s[1] |
| Declination | +36° 29′ 37.28″[1] |
| Redshift | 0.010764[2] |
| Helio radial velocity | 3210 ± 28 km/s[2] |
| Apparent magnitude (V) | 12.2[3] |
| Absolute magnitude (V) | −22.39[4] |
| Characteristics | |
| Type | E1[5] |
| Other designations | |
| UGC 9161, MCG+06-31-093, PGC 51104[2] | |
NGC 5557 is an elliptical galaxy in the constellation Boötes. It was discovered by William Herschel on May 1, 1785.[3] The distance to NGC 5557 is not well known, but it is estimated to be about 127 million light-years (38.8 megaparsecs) away.[5]
NGC 5557 is quite massive, with a K-band absolute magnitude of −24.8, and is a slow rotator,[5] which suggests it gained mass through dry mergers (galaxy mergers involving galaxies significant amounts of gas).[4] However, it has a faint tidal tail to its east, as well as a more complex structure to the west. This structure, if found to be connected to NGC 5557, would one of the largest around a galaxy, spanning about 1.1 million light-years (350,000 parsecs).[5] This filamentary structure suggests that NGC 5557 may have formed from a more gas-rich galaxy merger a couple billion years ago.[5] This implies that the galaxy merger would need to have a low impact parameter.[4]
NGC 5557 is part of a galaxy group,[5][3] and is the largest such galaxy in the group by far.[5] Surrounding the galaxy near the eastern filament are several small bluish objects, which are possibly tidal dwarf galaxies.[5]
Supernovae
Two supernovae have been observed in NGC 5557:
- SN 1996aa (type Ia, mag. 17) was discovered by Wayne Johnson on 16 May 1996.[6][7]
- SN 2013gn (type Ia, mag. 15.3) was discovered by Kōichi Itagaki on 16 November 2013.[8][9]
References
- ↑ 1.0 1.1 Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W. et al. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal 131 (2): 1163–1183. doi:10.1086/498708. ISSN 0004-6256. Bibcode: 2006AJ....131.1163S.
- ↑ 2.0 2.1 2.2 "NGC 5557". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+5557.
- ↑ 3.0 3.1 3.2 Seligman, Courtney. "New General Catalogue objects: NGC 5550 - 5599". http://cseligman.com/text/atlas/ngc55a.htm#5557.
- ↑ 4.0 4.1 4.2 Bonfini, Paolo (2014). "GALFIT-CORSAIR: Implementing the Core-Sérsic Model into GALFIT". Publications of the Astronomical Society of the Pacific 126 (944): 935–947. doi:10.1086/678566. Bibcode: 2014PASP..126..935B.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Cite error: Invalid
<ref>tag; no text was provided for refs namedDuc - ↑ Johnson, W.; Garnavich, P.; Riess, A.; Kirshner, R.; Barton, E. (1996). "Supernova 1996aa in NGC 5557". International Astronomical Union Circular (6403): 1. Bibcode: 1996IAUC.6403....1J. http://www.cbat.eps.harvard.edu/iauc/06400/06403.html#Item1.
- ↑ "SN 1996aa". IAU. https://www.wis-tns.org/object/1996aa.
- ↑ Nakano, S.; Yusa, T.; Ueno, I.; Itoh, R.; Kawabata, K. S.; Yamanaka, M.; Ayani, K.; Yamaoka, H. (2013). "Supernova 2013gn in NGC 5557 = PSN J14182850+3630244". Central Bureau Electronic Telegrams (3727): 1. Bibcode: 2013CBET.3727....1N.
- ↑ "SN 2013gn". IAU. https://www.wis-tns.org/object/2013gn.
External links
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