NGC 1637

NGC 1637
Very Large Telescope image of NGC 1637.
Observation data (J2000 epoch)
Constellation	Eridanus
Right ascension	04^h 41^m 28.229^s[1]
Declination	−02° 51′ 28.94″[1]
Redshift	0.00239[2]
Heliocentric radial velocity	717.1±1.2 km/s[2]
Distance	9.77 ± 1.82 Mpc (31.9 ± 5.9 Mly)[3] 9.18 Mpc (29.9 Mly) h^−1 0.73[4]
Apparent magnitude (V)	11.5[5]
Apparent magnitude (B)	11.25[6]
Characteristics
Type	SAB(rs)c[3] or SBc(s)II.3[7]
Size	~57,000 ly (17.48 kpc) (estimated)[5]
Apparent size (V)	4.0′ × 3.2′[5]
Other designations
AGC 440323, IRAS 04389-0257, UGCA 93, MCG +00-12-068, PGC 15821, CGCG 393-066[5]

NGC 1637 is an isolated, non-interacting[7] intermediate spiral galaxy in the constellation Eridanus, about a degree to the WNW of the star Mu Eridani.[8] It was discovered by German-British astronomer William Herschel on 1 February 1786.[9] It is located at a distance of about 9.77 ± 1.82 Mpc (31.9 ± 5.9 Mly) from the Milky Way.[3] The galaxy is inclined at an angle of 31.1° to the line of sight from the Earth and the long axis is oriented along a position angle of 16.3°.[3]

In 1991, Gérard de Vaucouleurs and associates assigned a morphological classification of SAB(rs)c to NGC 1637, indicating a spiral galaxy with a weak bar structure (SAB) across the nucleus, surrounded by a partial ring (rs) and somewhat loosely-wound arms (c).[7] While the inner section of the galaxy shows a symmetrical two-arm structure,[6] it has a single outer spiral arm that wraps 180° around the nucleus,[6] giving the galaxy an overall asymmetric, lopsided appearance.[7] The outer spiral arm has a red component that indicates a significant age.[6] However, the existence of this structure is difficult to explain.[7] The galaxy shows indications of recent starburst activity that may have terminated around 15 million years ago.[6]

The active central nucleus shows weak LINER behavior, and it may be an intermediate form between a LINER and an H II region.[7] The luminosity of the X-ray source at the nucleus is 1.2×10^38 ergs s^−1 in the 0.3–7 keV band.[6]

Supernova

One supernova has been observed in NGC 1637. SN 1999em (type II-P, mag. 13.5) was discovered by the Lick Observatory Supernova Search (LOSS) on 29 October 1999, at an angular separation of 24″ to the southwest of the galaxy center.[10][11] It was the brightest supernova discovered that year, reaching magnitude 13.1.[12] The location corresponds to a deprojected galactocentric separation of 1.3 kpc (4.2 kly).[3]

Image and Video Gallery

• 
  NGC 1637 imaged by the Hubble Space Telescope
• Video showing the location of NGC 1637

See also

• List of NGC objects (1001–2000)

References

1. Skrutskie, Michael F.; Cutri, Roc M.; Stiening, Rae; Weinberg, Martin D.; Schneider, Stephen E.; Carpenter, John M.; Beichman, Charles A.; Capps, Richard W.; Chester, Thomas; Elias, Jonathan H.; Huchra, John P.; Liebert, James W.; Lonsdale, Carol J.; Monet, David G.; Price, Stephan; Seitzer, Patrick; Jarrett, Thomas H.; Kirkpatrick, J. Davy; Gizis, John E.; Howard, Elizabeth V.; Evans, Tracey E.; Fowler, John W.; Fullmer, Linda; Hurt, Robert L.; Light, Robert M.; Kopan, Eugene L.; Marsh, Kenneth A.; McCallon, Howard L.; Tam, Robert; Van Dyk, Schuyler D.; Wheelock, Sherry L. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708. ISSN 0004-6256. S2CID 18913331.
2. Haynes, Martha P.; et al. (January 1998). "Asymmetry in High-Precision Global H i Profiles of Isolated Spiral Galaxies". The Astronomical Journal. 115 (1): 62–79. Bibcode:1998AJ....115...62H. doi:10.1086/300166. S2CID 123380349.
3. Crowther, Paul A. (January 2013). "On the association between core-collapse supernovae and H ii regions". Monthly Notices of the Royal Astronomical Society. 428 (3): 1927–1943. arXiv:1210.1126. Bibcode:2013MNRAS.428.1927C. doi:10.1093/mnras/sts145.
4. "NASA/IPAC Extragalactic Database". Results for NGC 1512, Co-Moving Radial Distance. Retrieved 2014-12-18.
5. "NASA/IPAC Extragalactic Database". Results for NGC 1637. Retrieved 2006-11-25.
6. Immler, Stefan; et al. (October 2003). "A Deep Chandra X-Ray Observation of NGC 1637". The Astrophysical Journal. 595 (2): 727–742. Bibcode:2003ApJ...595..727I. doi:10.1086/377474.
7. Sohn, Young-Jong; Davidge, T. J. (January 1998). "VRI CCD Photometry of Supergiant Stars in the Barred Galaxies NGC 925 and NGC 1637". The Astronomical Journal. 115 (1): 130–143. Bibcode:1998AJ....115..130S. doi:10.1086/300163.
8. Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 1. Sky Publishing Corporation and the European Space Agency. ISBN 0-933346-84-0.
9. Seligman, Courtney. "New General Catalogue Objects: NGC 1637". Celestial Atlas. Retrieved 30 November 2024.
10. Li, W. D. (1999). "Supernova 1999em in NGC 1637". International Astronomical Union Circular (7294): 1. Bibcode:1999IAUC.7294....1L.
11. "SN 1999em". Transient Name Server. IAU. Retrieved 30 November 2024.
12. Bishop, David. "Bright Supernovae - 1999 : SN 1999em". Astronomy Section, Rochdale Academy of Science. Retrieved 2024-11-30.

External links

• Media related to NGC 1637 at Wikimedia Commons