Astronomy:NGC 4194

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NGC 4194
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension 12h 14m 09.64s[1]
Declination+54° 31′ 34.60″[1]
Redshift0.008433[2]
Helio radial velocity2,511±12 km/s[3]
Distance (comoving)0 ± 0 Mly (000 ± 00 Mpc)h−10.73
Distance128 Mly (39.1 Mpc)[4]
Apparent magnitude (V)13.30[5]
Apparent magnitude (B)13.79[5]
Characteristics
TypeImeger[2]
Apparent size (V)0.14′ × 0.13′[6]
Notable featuresInteracting, starburst
Other designations
Medusa galaxy merger, NGC 4194, Arp 160, UGC 7241, PGC 39068[7]

NGC 4194, the Medusa merger, is a galaxy merger in the constellation Ursa Major about 128 million light-years (39.1 Mpc) away.[4] It was discovered on April 2, 1791 by German-British astronomer William Herschel.[8] Due to its disturbed appearance, it is object 160 in Halton Arp's 1966 Atlas of Peculiar Galaxies.[7]

A black hole in Medusa's tail

The morphological classification of NGC 4194 is Imeger,[2] indicating an irregular form. This galaxy consists of a brighter central region spanning an angular size 9″ across, with an accompanying system of loops and arcs. Additional material is thinly spread out to a radius of 75″ from the central region.[9] There is a tidal tail and regions undergoing high levels of star formation, making this a starburst galaxy. It is a source for strong infrared and radio emission.[10][11] These features indicate NGC 4194 is a late-stage galaxy merger.[12] A region of extreme star formation 500 ly (150 pc) across exists in the center of the Eye of Medusa, the central gas-rich region.[13]

Within 1.2 kpc (3.9 kly) of the dynamic center of NGC 4194, star formation is occurring at a rate of 8 M☉·yr−1. The star forming regions in this volume range from 5 to 9 million years in age, with the youngest occurring in areas of the highest star formation rate.[14] As of 2014, no galactic nucleus has been detected based on radio emissions, nor have the respective nuclei of the merger galaxies.[15] However, X-ray emission from a black hole in the tidal tail was detected by Chandra in 2009.[16]

References

  1. ↑ 1.0 1.1 Samsonyan, Anahit et al. (September 2016). "Neon and [C II] 158 μm Emission Line Profiles in Dusty Starbursts and Active Galactic Nuclei". The Astrophysical Journal Supplement Series 226 (1): id. 11. doi:10.3847/0067-0049/226/1/11. Bibcode: 2016ApJS..226...11S. 
  2. ↑ 2.0 2.1 2.2 Ann, H. B. et al. (2015). "A Catalog of Visually Classified Galaxies in the Local (z ~ 0.01) Universe". The Astrophysical Journal Supplement Series 217 (2): 27–49. doi:10.1088/0067-0049/217/2/27. Bibcode: 2015ApJS..217...27A. 
  3. ↑ Falco, Emilio E. et al. (April 1999). "The Updated Zwicky Catalog (UZC)". Publications of the Astronomical Society of the Pacific 111 (758): 438. doi:10.1086/316343. Bibcode: 1999PASP..111..438F. 
  4. ↑ 4.0 4.1 Lianou, S. et al. (November 2019). "Dust properties and star formation of approximately a thousand local galaxies". Astronomy & Astrophysics 631: 19. doi:10.1051/0004-6361/201834553. A38. Bibcode: 2019A&A...631A..38L. 
  5. ↑ 5.0 5.1 Véron-Cetty, M.-P.; Véron, P. (2010). "A catalogue of quasars and active nuclei: 13th edition". Astronomy & Astrophysics 518 (A10): A10. doi:10.1051/0004-6361/201014188. Bibcode: 2010A&A...518A..10V. 
  6. ↑ "Results for NGC 4194". NASA/IPAC Extragalactic Database. Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. January 12, 2007. http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+4194. 
  7. ↑ 7.0 7.1 "NGC 4194". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+4194. 
  8. ↑ Seligman, Courtney. "NGC Objects: NGC 4150 - 4199". Celestial Atlas. https://cseligman.com/text/atlas/ngc41a.htm#4194. 
  9. ↑ Demoulin, Marie-Helene (April 1969). "The Peculiar Galaxy NGC 4194". Astrophysical Journal 156: 325. doi:10.1086/149967. Bibcode: 1969ApJ...156..325D. 
  10. ↑ Weistrop, D. et al. (March 2004). "Looking Closely at Medusa: Star-forming Knots at the Center of NGC 4194". The Astronomical Journal 127 (3): 1360–1370. doi:10.1086/382092. Bibcode: 2004AJ....127.1360W. 
  11. ↑ Hancock, M. et al. (December 2003). "A Spectroscopic Study of the Star-Forming Properties of the Center of NGC 4194". The Astronomical Journal 131 (1): 1394. doi:10.1086/497969. Bibcode: 2003AAS...20311515H. 
  12. ↑ Joseph, R. D.; Wright, G. S. (May 1985). "Recent star formation in interacting galaxies - II. Super starbursts in merging galaxies". Monthly Notices of the Royal Astronomical Society 214 (2): 87–95. doi:10.1093/mnras/214.2.87. Bibcode: 1985MNRAS.214...87J. 
  13. ↑ "Unknown extreme star formation discovered". Space Daily. 17 June 2015. http://www.spacedaily.com/reports/Unknown_extreme_star_formation_discovered_999.html. 
  14. ↑ Weistrop, D. et al. (April 2012). "Characteristics of Star-forming Regions in the Advanced Minor-merger, Luminous Infrared Galaxy NGC 4194". The Astronomical Journal 143 (4): id. 98. doi:10.1088/0004-6256/143/4/98. Bibcode: 2012AJ....143...98W. 
  15. ↑ Beck, Sara C. et al. (May 2014). "Ionized Gas Kinematics at High Resolution. IV. Star Formation and a Rotating Core in the Medusa (NGC 4194)". The Astrophysical Journal 787 (1): id. 85. doi:10.1088/0004-637X/787/1/85. Bibcode: 2014ApJ...787...85B. 
  16. ↑ "NGC 4194: A Black Hole in Medusa's Hair". Chandra Photo Album. March 11, 2009. https://chandra.harvard.edu/photo/2009/medusa/. 

Further reading

Coordinates: Sky map 12h 14m 09.5s, +54° 31′ 37″



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