The Sculptor Galaxy taken with the ESO VISTA telescope at the Paranal Observatory in Chile.
|Observation data (J2000 epoch)|
|Right ascension||00h 47m 33s|
|Declination||-25° 17′ 18″|
|Helio radial velocity||243 ± 2 km/s |
|Distance||11.4 ± 0.7 Mly
(3.5 ± 0.2 Mpc)
|Apparent dimensions (V)||27′.5 × 6′.8|
|Apparent magnitude (V)||8.0|
|Silver Coin Galaxy, Silver Dollar Galaxy, NGC 253, UGCA 13, PGC 2789 Caldwell 65|
The Sculptor Galaxy (also known as the Silver Coin or Silver Dollar Galaxy, NGC 253, or Caldwell 65) is an intermediate spiral galaxy in the constellation Sculptor. The Sculptor Galaxy is a starburst galaxy, which means that it is currently undergoing a period of intense star formation.
Observational history 
The galaxy was discovered by Caroline Herschel in 1783 during one of her systematic comet searches. About half a century later, John Herschel observed it using his 18 inch metallic mirror reflector at the Cape of Good Hope. He wrote, "very bright and large (24′ in length); a superb object.... Its light is somewhat streaky, but I see no stars in it except 4 large and one very small one, and these seem not to belong to it, there being many near..."
In 1961 Allan Sandage wrote in the Hubble Atlas of Galaxies that the Sculptor Galaxy is "the prototype example of a special subgroup of Sc systems....photographic images of galaxies of the group are dominated by the dust pattern. Dust lanes and patches of great complexity are scattered throughout the surface. Spiral arms are often difficult to trace.... The arms are defined as much by the dust as by the spiral pattern." Bernard Y. Mills, working out of Sydney, discovered that the Sculptor Galaxy is also a fairly strong radio source.
NGC 253's most notable feature is the mentioned starburst that is taking place of it and that has created several super star clusters on NGC 253's center discovered with the aid of the Hubble Space Telescope: one with a mass of 1,5*106 solar masses, and absolute magnitude of at least -15 and two others with 5*104 solar masses and absolute magnitudes around -11; later studies have discovered an even more massive cluster heavily obscured by NGC 253's interstellar dust with a mass of 1,4*107 solar masses, an age of around 5,7*106 years, and rich in Wolf-Rayet stars.
Star formation is also high in the northeast of NGC 253's disk, where a number of red supergiant stars can be found, and on its halo are present young stars as well as some amounts of neutral hydrogen. This, along other peculiarities found on NGC 253, suggest a gas-rich dwarf galaxy collided with it 200 million years ago, disturbing its disk and starting the present starburst.
Although supernovae are generally associated with starburst galaxies, only one supernova has been detected within the Sculptor Galaxy. The supernova, named SN 1940E, is located approximately 54″ southwest of the galaxy's nucleus. It was discovered in November 1940.
Recent distance estimates 
At least two techniques have been used to measure distances to Sculptor in the past ten years.
Sculptor is close enough that the tip of the red giant branch (TRGB) method may also be used to estimate its distance. The estimated distance to Sculptor using this technique in 2004 yielded 12.8 ± 1.2 Mly (3.94 ± 0.37 Mpc).
A weighted average of the most reliable distance estimates gives a distance of 11.4 ± 0.7 Mly (3.5 ± 0.2 Mpc).
Galaxy group information 
The Sculptor Galaxy is located at the center of the Sculptor Group, one of the nearest groups of galaxies to the Milky Way. The Sculptor Galaxy (the brightest galaxy in the group) and the companion galaxies NGC 247, PGC 2881, PGC 2933, Sculptor-dE1, and UGCA 15 form a gravitationally bound core near the center of the group. Most other galaxies associated with the Sculptor Group are only weakly gravitationally bound to this core.
Amateur observation 
Observations with binoculars 
As one of the brightest galaxies in the sky, the Sculptor Galaxy can be seen through binoculars and is near the star Beta Ceti. It is considered one of the most easily viewed galaxies in the sky after the Andromeda Galaxy.
Observations with amateur telescopes 
The Sculptor Galaxy is a good target for observation with a telescope with a 300 mm diameter or larger. In such telescopes, it appears as a galaxy with a long, oval bulge and a mottled disk. Although the bulge appears only slightly brighter than the rest of the galaxy, it is fairly extended compared to the disk. In 400 mm scopes and larger, a dark dust lane northwest of the nucleus is visible, and over a dozen faint stars can be seen superimposed on the bulge.
In popular culture 
See also 
- Globular cluster NGC 288 is located 1°.8 south-southeast of the Sculptor Galaxy.
- 2MASX J00482185-2507365 occulting pair discovered while photographing NGC 253
- "NASA/IPAC Extragalactic Database". Results for NGC 253. Retrieved 2006-11-25.
- Rekola, R.; Richer, M. G.; McCall, Marshall L.; Valtonen, M. J.; Kotilainen, J. K.; Flynn, Chris (2005). "Distance to NGC 253 based on the planetary nebula luminosity function". Monthly Notices of the Royal Astronomical Society 361 (1): 330–336. Bibcode:2005MNRAS.361..330R. doi:10.1111/j.1365-2966.2005.09166.x.
- "NGC 253: Dusty Island Universe". NASA Astro Pic of the Day. 2006-04-21. Retrieved 2010-12-04.
- O'Meara, Stephen James (2002). The Caldwell Objects. Cambridge University Press. ISBN 0-521-82796-5.
- Dreyer, J. L. E. (1888). "A New General Catalogue of Nebulae and Clusters of Stars,being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged". Memoirs of the Royal Astronomical Society 49: 1–237. Bibcode:1888MmRAS..49....1D.
- Burnham, Robert (1978). Burnham's Celestial Handbook; An Observers Guide to the Universe Beyond the Solar System; Volume Three, Pavo Through Vulpecula. Dover Publications, Inc. p. 1736. ISBN 0-486-24065-7.
- Sandage, Allan (1961). The Hubble atlas of galaxies. Washington: Carnegie Institution. ISBN 0-87279-629-9.
- "HubbleSite NewsCenter". Results for NGC 253. Retrieved 2007-04-05.
- Watson, A. M.; Gallagher, J. S., III; Holtzman, J. A.; Hester, J. J.; Mould, J. R.; Ballester, G. E.; Burrows, C. J.; Casertano, S.; Clarke, J. T.; Crisp, D.; Evans, R.; Griffiths, R. E.; Hoessel, J. G.; Scowen, P. A.; Stapelfeldt, K. R.; Trauger, J. T.; Westphal, J. A. (1996). "The Discovery of Young, Luminous, Compact Stellar Clusters in the Starburst Galaxy NGC 253". Astronomical Journal 112: 534. Bibcode:1996AJ....112..534W. doi:10.1086/118032.
- Kornei, Katherine A.; McCrady, Nate (2009). "A Young Super Star Cluster in the Nuclear Region of NGC 253". The Astrophysical Journal 697 (2): 1180–1186. Bibcode:2009ApJ...697.1180K. doi:10.1088/0004-637X/697/2/1180.
- Davidge, T. J. (2010). "Shaken, Not Stirred: The Disrupted Disk of the Starburst Galaxy NGC 253". The Astrophysical Journal 725 (1): 1342–1365. Bibcode:2010ApJ...725.1342D. doi:10.1088/0004-637X/725/1/1342.
- R. Barbon, E. Cappellaro, F. Ciatti, M. Turatto, C. T. Kowal; Cappellaro; Ciatti; Turatto; Kowal (1984). "A revised supernova catalogue". Astronomy & Astrophysics Supplement Series 58: 735–750. Bibcode:1984A&AS...58..735B.
- I. D. Karachentsev, V. E. Karachentseva, W. K. Hutchmeier, D. I. Makarov (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
- Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6.
- I. D. Karachentsev (2005). "The Local Group and Other Neighboring Galaxy Groups". Astronomical Journal 129 (1): 178–188. arXiv:astro-ph/0410065. Bibcode:2005AJ....129..178K. doi:10.1086/426368.
- I. D. Karachentsev, E. K. Grebel, M. E. Sharina, A. E. Dolphin, D. Geisler, P. Guhathakrta, P. W. Hodge, V. E. Karachentseva, A. Sarajedini, P. Seitzer (2003). "Distances to nearby galaxies in Sculptor". Astronomy and Astrophysics 404 (1): 93–111. arXiv:astro-ph/0302045. Bibcode:2003A&A...404...93K. doi:10.1051/0004-6361:20030170.
- Kepple, George Robert; Glen W. Sanner (1998). The Night Sky Observer's Guide, Volume 2. Willmann-Bell, Inc. pp. 365, 371. ISBN 0-943396-60-3.
- STScI news release: Hubble Probes the Violent Birth of Stars in Galaxy NGC 253
- STScI news release: Behind a Dusty Veil Lies a Cradle of Star Birth
- Sculptor Galaxy on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images