UGC 6945

UGC 6945 (also known as Arp 194) is a trio of interacting galaxies. The highly disrupted galaxy to the northwest is actually two galaxies in the advanced stages of merger, and has an angular size of 0′.8 × 0′.6. About 40″ to the southeast is a third galaxy with an angular size of 0′.35 × 0′.35.

UGC 6945
UGC 6945 by Hubble Space Telescope
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension11h 57m 54.87s[1]
Declination+36° 23′ 32.8″[1]
Redshift0.035388 ± 0.000130[2]
Heliocentric radial velocity+10,511 km s−1[2]
Distance175 Mpc (570 Mly)
Characteristics
TypeS?[3]
Apparent size (V)1.202′[4]
Other designations
Arp 194, VV 126

Based upon a radial velocity of about 10,500 km s−1, the interacting pair of galaxies at the northwest are located at a distance of 175 Mpc (570 Mly) from us (assuming a Hubble constant value of 60 km s−1 Mpc−1). If we further assume that the third galaxy lies at the same distance away from us, we find that the galaxies are separated by a projected linear distance of roughly 34 Kpc (110 Kly),[5] though later findings from Hubble may cast this assumption into doubt (see below)

As the pair of galaxies in the north gravitationally interact with each other, tidally-stripped gas from both galaxies is draped over the southern galaxy as a series of blobs, which are fueling a burst of star formation.[5] While it has long been believed to be interacting with the northern galaxy, images from the Hubble Space Telescope clearly show that this stream of material is actually superimposed on the southern galaxy.[6] This suggests that this third galaxy may actually lie in the background. Due to this uncertainty, the third galaxy may not be involved in the interaction.

See also

References
  1. Cotton, W. D.; Condon, J. J.; Arbizzani, E. (December 1999). "Arcsecond Positions of UGC Galaxies". The Astrophysical Journal Supplement Series. 125 (2): 409–412. Bibcode:1999ApJS..125..409C. doi:10.1086/313286.
  2. Huchra, John P.; Geller, Margaret J.; Corwin, Harold G., Jr. (August 1995). "The CfA Redshift Survey: Data for the NGP +36 Zone". The Astrophysical Journal Supplement Series. 99: 391. Bibcode:1995ApJS...99..391H. doi:10.1086/192191. ISSN 0067-0049.
  3. "Results for object NGC UGC 6945 (UGC 6945)". NASA/IPAC Extragalactic Database. California Institute of Technology. Retrieved 2021-02-28.
  4. "UGC 6945 -- Interacting Galaxies". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2011-03-11.
  5. Marziani, P.; Dultzin-Hacyan, D.; D'Onofrio, M.; Sulentic, J. W. (April 2003). "Arp 194: Evidence of Tidal Stripping of Gas and Cross-Fueling". The Astronomical Journal. 125 (4): 1897–1907. arXiv:astro-ph/0212547. Bibcode:2003AJ....125.1897M. doi:10.1086/368142. S2CID 210847.
  6. "Hubble Celebrates Its 19th Anniversary with a". HubbleSite.org. Retrieved 2020-02-17.


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