Astronomy:NGC 1637
| NGC 1637 | |
|---|---|
 NGC 1637 imaged by the Very Large Telescope | |
| Observation data (J2000 epoch) | |
| Constellation | Eridanus |
| Right ascension | 04h 41m 28.229s[1] |
| Declination | −02° 51′ 28.94″[1] |
| Redshift | 0.00239[2] |
| Helio 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−10.73[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, MCG+00-12-068, PGC 15821[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][10] 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 1.2×1038 ergs s−1 in the 0.3–7 keV band.[6]
Supernovae
Two supernovae have 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.[11][12] It was the brightest supernova discovered that year, reaching magnitude 13.1.[13] The location corresponds to a deprojected galactocentric separation of 1.3 kpc (4.2 kly).[3]
- SN 2025pht (Type II-P, mag. 13.3) was discovered by All Sky Automated Survey for SuperNovae on 29 June 2025.[14] A study of archival images taken with the Hubble Space Telescope and the James Webb Space Telescope found a suspected progenitor, a red supergiant star with a mass of ~15M☉.[15]
Image and Video Gallery
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NGC 1637 imaged by the Hubble Space Telescope -
Video showing the location of NGC 1637
See also
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 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. doi:10.1086/300166. Bibcode: 1998AJ....115...62H.
- ↑ 3.0 3.1 3.2 3.3 3.4 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. doi:10.1093/mnras/sts145. Bibcode: 2013MNRAS.428.1927C.
- ↑ "NASA/IPAC Extragalactic Database". Results for NGC 1512, Co-Moving Radial Distance. http://nedwww.ipac.caltech.edu/.
- ↑ 5.0 5.1 5.2 5.3 "NASA/IPAC Extragalactic Database". Results for NGC 1637. http://nedwww.ipac.caltech.edu/.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Immler, Stefan et al. (October 2003). "A Deep Chandra X-Ray Observation of NGC 1637". The Astrophysical Journal 595 (2): 727–742. doi:10.1086/377474. Bibcode: 2003ApJ...595..727I.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 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. doi:10.1086/300163. Bibcode: 1998AJ....115..130S.
- ↑ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. 1. Sky Publishing Corporation and the European Space Agency. ISBN 0-933346-84-0.
- ↑ Herschel, W. (1789). "Catalogue of a Second Thousand of New Nebulae and Clusters of Stars; with a Few Introductory Remarks on the Construction of the Heavens". Philosophical Transactions of the Royal Society of London 79: 212–255. doi:10.1098/rstl.1789.0021. Bibcode: 1789RSPT...79..212H.
- ↑ Seligman, Courtney. "New General Catalogue Objects: NGC 1637". https://cseligman.com/text/atlas/ngc16.htm#1637.
- ↑ Li, W. D. (1999). "Supernova 1999em in NGC 1637". International Astronomical Union Circular (7294): 1. Bibcode: 1999IAUC.7294....1L.
- ↑ "SN 1999em". IAU. https://www.wis-tns.org/object/1999em.
- ↑ Bishop, David. "Bright Supernovae - 1999 : SN 1999em". Astronomy Section, Rochdale Academy of Science. https://www.rochesterastronomy.org/snimages/sn1999/#1999em.
- ↑ "SN 2025pht". IAU. https://www.wis-tns.org/object/2025pht.
- ↑ Kilpatrick, Charles D.; Suresh, Aswin; Davis, Kyle W.; Drout, Maria R.; Foley, Ryan J.; Gagliano, Alexander; Jacobson-Galan, Wynn V.; Kaur, Ravjit; Taggart, Kirsty; Vazquez, Jason (2025). "The Type II SN 2025pht in NGC 1637: A Red Supergiant with Carbon-rich Circumstellar Dust as the First JWST Detection of a Supernova Progenitor Star". arXiv:2508.10994 [astro-ph.HE].
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