NGC 7723 is abarred spiral galaxy located in the constellationAquarius. It is located at a distance of about 90 millionlight years from Earth, which, given its apparent dimensions, means that NGC 7723 is about 95,000 light years across. It was discovered byWilliam Herschel on November 27, 1785.[3] The galaxy is included in theHerschel 400 Catalogue. It lies 1.5 degrees north-northwest fromOmega1 Aquarii. It can be seen with a 4-inchtelescope under dark skies.[4]
NGC 7723 is a barred spiral galaxy. It has a bright nucleus and a boxybulge.[5] In the centre of the galaxy lies asupermassive black hole whose mass is estimated to be(10.6±4.9)×106M☉ based on the spiral arm pitch angle.[6] The bar emerges from the opposite sides of the bulge.[5] Straight dust lanes are observed along the bar, the one smooth and the other appearing broken.[7] The bar has a maximum apparent length of 64 arcseconds. At the end of the bar the spiral arms form a pseudoring with diameter of 71 arcseconds.[8] Based on observations infar ultraviolet (FUV) andHα there is activestar formation at the pseudoring.[9] Based on the B-I color profile of the galaxy the bar finishes at 23 arcseconds, at the same distance where there is a population of older stars, and thus is suggested to be thecorotation radius of NGC 7723.[10]
The structure of thearms is complex. The arm that emanates from the southwest part of the bar is well defined for a quarter of a revolution and after that it becomes more diffuse and fades after reaching half a revolution. The other arm emanates from a feature about 60 degrees northwest of the bar and brightens after passing the end of the bar, and then it splits in two. The inner part forms the southwest part of the pseudoring and bifurcates after winding for about 120 degrees after the bar end, with the inner part being the brightest. The other arm becomes diffuse and of low surface brightness.[5]
Onesupernova has been observed in NGC 7723: SN 1975N (type Ia, mag. 15) was discovered byPaul Wild on 24 October 1975.[11][12] It was also independently discovered by Valentin A. Lipovetsky on 27 October 1975.[13]
NGC 7723 belongs to a smallgroups of galaxies known as the NGC 7727 group. Other members of the group includeNGC 7727 andNGC 7724.[14] NGC 7727 lies about 40' northwest of NGC 7723.[7]
^abcEskridge, Paul B.; Frogel, Jay A.; Pogge, Richard W.; Quillen, Alice C.; Berlind, Andreas A.; Davies, Roger L.; DePoy, D. L.; Gilbert, Karoline M.; Houdashelt, Mark L.; Kuchinski, Leslie E.; Ramirez, Solange V.; Sellgren, K.; Stutz, Amelia; Terndrup, Donald M.; Tiede, Glenn P. (November 2002). "Near-Infrared and Optical Morphology of Spiral Galaxies".The Astrophysical Journal Supplement Series.143 (1):73–111.arXiv:astro-ph/0206320.Bibcode:2002ApJS..143...73E.doi:10.1086/342340.S2CID15491635.
^abSandage, A., Bedke, J. (1994),The Carnegie Atlas of Galaxies. Volume I, Carnegie Institution of Washington
^Comerón, S.; Salo, H.; Laurikainen, E.; Knapen, J. H.; Buta, R. J.; Herrera-Endoqui, M.; Laine, J.; Holwerda, B. W.; Sheth, K.; Regan, M. W.; Hinz, J. L.; Muñoz-Mateos, J. C.; Gil de Paz, A.; Menéndez-Delmestre, K.; Seibert, M.; Mizusawa, T.; Kim, T.; Erroz-Ferrer, S.; Gadotti, D. A.;Athanassoula, E.; Bosma, A.; Ho, L. C. (19 February 2014). "ARRAKIS: atlas of resonance rings as known in the S4G".Astronomy & Astrophysics.562: A121.arXiv:1312.0866.Bibcode:2014A&A...562A.121C.doi:10.1051/0004-6361/201321633.S2CID119295831.
^Aguerri, J. A. L.; Muñoz-Tuñón, C.; Varela, A. M.; Prieto, M. (September 2000). "Characterizing bar structures: application to NGC 1300, NGC 7479 and NGC 7723".Astronomy and Astrophysics.361:841–849.Bibcode:2000A&A...361..841A.
^Wild, P. (1975). "Supernova in NGC 7723".International Astronomical Union Circular (2858): 1.Bibcode:1975IAUC.2858....1W.
^"SN1975N".Transient Name Server.IAU. Retrieved3 December 2024.
^Martynov, D. Ya.; Lipovetskij, V. A. (1975). "Supernova in NGC 7723".International Astronomical Union Circular (2859): 1.Bibcode:1975IAUC.2859....1M.
