NGC 5173
Galaxy in the constellation Canes Venatici
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NGC 5173 is a peculiar elliptical galaxy in the northern constellation of Canes Venatici. It was discovered May 12, 1787 by German-British astronomer William Herschel.[7] This galaxy has an apparent visual magnitude of 12.2,[1] and spans an angular size of 1.2′ × 1.1′.[5] It is the second brightest member of a small group of galaxies, with the brightest being NGC 5198; it lies at the eastern edge of its group.[8] NGC 5171 is separated from the nearby Sb galaxy NGC 5169 by just 5.5′, and they have a velocity difference of 17 km/s.[9]
| NGC 5173 | |
|---|---|
NGC 5173 imaged by the DESI Legacy Surveys | |
| Observation data (J2000 epoch) | |
| Constellation | Canes Venatici[1] |
| Right ascension | 13h 28m 25.280s[2] |
| Declination | +46° 35′ 29.89″[2] |
| Heliocentric radial velocity | 2,419 km/s[3] |
| Distance | 125 ± 23 Mly (38.3 ± 7.0 Mpc)[4] |
| Apparent magnitude (V) | 12.2[1] |
| Apparent magnitude (B) | 13.2[1] |
| Surface brightness | 12.2[1] |
| Characteristics | |
| Type | SA[3] |
| Apparent size (V) | 1.191′ × 1.066′[5] |
| Other designations | |
| NGC 5173, UGC 8468, LEDA 47257, MCG +08-25-005, PGC 47257[6][3] | |
Originally, this was classified by de Vaucouleurs as an elliptical galaxy, having a morphological classification of E0:[10] which indicates a spherically-symmetric shape.[11] In 1984, neutral hydrogen gas was discovered in NGC 5171, with a mass estimated at ~109 M☉ being about double that of gas-rich ellipticals.[11]
Observations reported in 1991 showed the presence of a star-forming spiral structure[8][10] located off-center from the galaxy isophotes.[3] This may be the remnant of an accreted galaxy similar to the Large Magellanic Cloud,[8] with at least 10–20% of the original galaxy's mass.[12] The disk has a radial extent of about 3.5 to 9.5 kpc.[8] Massive clusters have formed in this disk over the last 400 Myr.[12] Observations with the Hubble Space Telescope show filamentary structures at the center of the galaxy.[13]