NGC 3607

NGC 3607 is a small but fairly bright^[7] lenticular galaxy^[3] in the equatorial constellation of Leo, about 2.5° south of the prominent star Delta Leonis.^[8] The galaxy was discovered March 14, 1784 by William Herschel. Dreyer described it as "very bright, large, round, very much brighter middle, 2nd of 3".^[9] It is located at a distance of 73 million light years and is receding with a radial velocity of 930 km/s.^[2] The galaxy lies southwest of NGC 3626 at an angular separation of ~50′.^[7] It occupies the center of the Leo II Group of galaxies, forming one of its two brightest members – the other being NGC 3608.^[3] It is a member of the NGC 3607 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster.^[10]

NGC 3607
The nuclear dust disk of NGC 3607 as imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation	Leo
Right ascension	11h 16m 54.657s[1]
Declination	+18° 03′ 06.51″[1]
Heliocentric radial velocity	930 km/s[2]
Distance	73.4 Mly (22.49 Mpc)[2]
Group or cluster	Leo II Group[3]
Apparent magnitude (V)	10.8[4]
Characteristics
Type	SA(s)0*[5]
Apparent size (V)	4.9′ × 2.5′[4] (Optical)
Other designations
2MASX J11165465+1803065, NGC 3607, UGC 6297, PGC 34426, SDSS J111654.63+180306.3, SDSS J111654.63+180306.3[6]

The morphological class of NGC 3607 is SA(s)0*,^[5] matching a lenticular galaxy (SA0) with no inner ring structure (s). It is an intermediate mass galaxy^[3] that is being viewed at an inclination of 34°,^[5] showing an ellipticity of 0.13 with the major axis oriented along a position angle of 125°.^[3] The galaxy has an outer dusty disk with a second perpendicular disk that is falling inward toward the center of the galaxy.^[3] X-ray emission from hot gas has been detected in the interior and from all around the galaxy.^[5]

A system of 46 confirmed globular clusters have been identified around NGC 3607, which are orbiting within an effective radius of 14.2±2.0 kpc. In contrast, the stellar component of the galaxy has an effective radius of 4.2±1 kpc.^[3] Orbital motions of this cluster system^[11] imply an unusual poverty of dark matter: perhaps 16%±44% of the total mass within 5 effective radii. Its central black hole has a mass of M_• = (1.2±0.4)×10⁸ M_☉^[12] The core region of the galaxy is kinematically distinct from the remainder of the galaxy and shows an enhancement of magnesium.^[5]