NGC 4624, NGC 4664,UGC 7924,CGCG 043-018,MCG +01-33-005,PGC 42970[1]
NGC 4665, also catalogued asNGC 4624 andNGC 4664, is abarred lenticular orspiral galaxy located in the constellationVirgo. It is a member of theVirgo II Groups, a series of galaxies andgalaxy clusters strung out from the southern edge of theVirgo Supercluster.[4] It is located at a distance of circa 60 millionlight years from Earth, which, given its apparent dimensions, means that NGC 4665 is about 75,000 light years across. NGC 4665 lies 2 and 3/4 degrees east-south east ofDelta Virginis and 50 arcminutes southwest of35 Virginis. It can be viewed through a moderately sizedtelescope with 23x magnification, forming a pair with an 11th magnitude star 1.5 arcminutes southwest. It is part of theHerschel 400 Catalogue.[5]
It was discovered byWilliam Herschel on February 23, 1784, however, he noted a location 10 arcminutes off the galaxy, where there is no object. It was observed by William Herschel again on April 30, 1786, noting the correct coordinates, and he misidentified it as another nebula. The fact that they are the same object was noted byJohn Louis Emil Dreyer in 1912 in the corrections of the New General Catalogue. It was also recorded independently on April 9, 1828 byJohn Herschel.[6]
NGC 4665 has a luminous, slightly elliptical bulge and a prominentbar with high surface brightness.[7] The isophotes appear boxy at the end of the bar.[8][9] The total bar length is estimated to be near 3 kpc.[10] The bar is slightly twisted, turning near 12 degrees along its axis.[11] Two diffuse, faint arms emerge from each side of the bar and form a pseudoring.[7] The surface brightness of the arms is higher near the bar.[12][13] The southern arm appears a bit stronger. An arch feature is observed at the east side of the galaxy that could be a partial outer dusty ring.[11] The outerisophotes are elliptical.[7] The total mass ofmolecular gas is less than107.3M☉.[14]
NGC 4665 belongs to the NGC 4636 group. Other members of the group includeNGC 4457,NGC 4586,NGC 4587,NGC 4600,NGC 4636, andNGC 4688.[15] These galaxies, along withNGC 4753,Messier 61 and their groups form the southern boundary of theVirgo cluster. It can be difficult to determine which galaxies belong to which group, especially around the southern edge of the Virgo cluster where there is a confusion of galaxies at different distances.[16]
^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.
