NGC 5170

NGC 5170
NGC 5170 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation	Virgo
Right ascension	13h 29m 48.769s[1]
Declination	−17° 57′ 59.39″[1]
Redshift	0.005006[2]
Heliocentric radial velocity	1,502 km/s[3]
Galactocentric velocity	1,386 km/s[3]
Distance	83.5 Mly (25.59 Mpc)[3]
Apparent magnitude (V)	12.4[2]
Apparent magnitude (B)	12.07[3]
Absolute magnitude (V)	−21.6[4]
Characteristics
Type	SA(s)c: sp[2]
Apparent size (V)	9′.9 × 1′.2[2]
Other designations
IRAS 13271-1742, NGC 5170, LEDA 47394, MCG -03-34-084, PGC 47394[3][5]

NGC 5170 is a large, nearby,^[6] edge-on spiral galaxy in the equatorial constellation of Virgo. It was discovered on February 7, 1785 by William Herschel. This galaxy is located at a distance of 83.5 million light years and is receding at a heliocentric radial velocity of 1,502 km/s.^[3] It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.^[7]

The inclination of the galactic plane of NGC 5170 is tilted at an angle of ~86° to the line of sight from the Earth, which means the disk is significantly obscured. It is estimated to have a morphological class of type Sb to Sc, meaning the spiral arms are moderate to loosely wound. The bulge-to-disk ratio of 0.5 is more consistent with an Sb galaxy.^[4] It has an estimated star formation rate of 1.37±0.23 M_☉·yr⁻¹, which is more than double the rate in the Milky Way.^[4]

The galactic latitude of this star is 43°, making the field relatively free of stars in the Milky Way. Combined with the proximity and edge-on view of NGC 5170, this makes galaxy useful for studies of its globular cluster population. It is estimated to have a total of 600±100 globulars, which is much higher than for the Milky Way. A candidate ultra-compact dwarf galaxy has been identified that is associated with NGC 5170.^[4]

Numerical modeling of this galaxy indicates it has a massive dark halo with a thin, low surface brightness disk.^[6] The halo mass of NGC 5170 is 3.4×10¹² M_☉.^[4] Examination of the galaxy with the Chandra X-ray Observatory showed there is no diffuse X-ray emission from hot gas in the extended galactic halo.^[8]

• Media related to NGC 5170 at Wikimedia Commons
• NGC 5170 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images