Arp 166

Arp 166 is a pair of interacting elliptical galaxies approximately 225 million light-years away from Earth in the constellation of Triangulum.[2][3] The two galaxies, NGC 750 and NGC 751, are listed together as Arp 166 in the Atlas of Peculiar Galaxies (in the category Galaxies with diffuse filaments).[4]

Arp 166
Arp 166 consists of NGC 750 (top) and NGC 751 (bottom) (SDSS)
Observation data (J2000.0 epoch)
ConstellationTriangulum
Right ascension01h 57m 32.00s [1]
Declination+33° 12′ 24.00″ [1]
Redshift0.017529 [2]
Helio radial velocity5255 km/s [2]
Distance225 Mly [3]
Apparent magnitude (B)12.90 [1]
Characteristics
TypePair of galaxies E0+E [2]
Apparent size (V)2.5 x 1.7 [2]
Other designations
NGC 750, NGC 751

Observational history

Arp 166 was discovered by German-born British astronomer William Herschel on September 12, 1784, but he did not resolve this close pair of galaxies, therefore he described it as a single object NGC 750.[4][3]

Arp 166 was first seen as a double by Irish engineer and astronomer Bindon Stoney on October 11, 1850, who used Lord Rosse's 72" telescope.[4] The second galaxy from this pair, which is smaller and fainter than NGC 750, was catalogued as NGC 751.[4]

Interacting galaxies

At least 100,000,000 years have passed since the moment of the first strong tidal perturbation between these two galaxies.[5] Both galaxies are characterized by strong tidal interactions and distortions, and they are still in the process of efficient tidal interaction.[5]

The distance between the centers of this pair is 21", or 10 kpc in projection.[6][5] Both galaxies have almost identical central radial velocities.[5] While NGC 750 exhibits nearly flat radial velocity curves, the radial velocity curves of NGC 751 are characterized by large variations of more than 100 km s−1 along the slit.[5]

A large, diffuse tidal tail extends 20 arcsec (10 kpc) to the north-east of the pair.[5]

See also

References
  1. "SIMBAD Astronomical Database". Retrieved March 7, 2019.
  2. "NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved March 7, 2019.
  3. "Focal Pointe Observatory". bf-astro.com. Retrieved March 7, 2019.
  4. "Data for NGC 750/751". www.astronomy-mall.com. Retrieved March 7, 2019.
  5. Madejsky, R. (1991). "Morphology and kinematics of the interacting elliptical galaxies NGC750 and NGC751 = ARP 166 - Velocity fields of tidally distorted elliptical galaxies". Astronomy and Astrophysics. 247: 348–356. Bibcode:1991A&A...247..348M.
  6. Sandage, A.; Bedke, J. (1994). The Carnegie Atlas of Galaxies. Volume I. Carnegie Institution of Washington. Bibcode:1994cag..book.....S.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.