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NGC 4194

Coordinates: Sky map 12h 14m 09.5s, +54° 31′ 37″
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This article is about a pair of interacting galaxies. For the Medusa planetary nebula, see Medusa Nebula.
NGC 4194
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension12h 14m 09.64s[1]
Declination+54° 31′ 34.60″[1]
Redshift0.008433[2]
Heliocentric radial velocity2,511±12 km/s[3]
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, Mrk 201, 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

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  1. ^ a b 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. arXiv:1608.02277. Bibcode:2016ApJS..226...11S. doi:10.3847/0067-0049/226/1/11.
  2. ^ a b c 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. arXiv:1502.03545. Bibcode:2015ApJS..217...27A. doi:10.1088/0067-0049/217/2/27. S2CID 119253507.
  3. ^ Falco, Emilio E.; et al. (April 1999). "The Updated Zwicky Catalog (UZC)". Publications of the Astronomical Society of the Pacific. 111 (758): 438. arXiv:astro-ph/9904265. Bibcode:1999PASP..111..438F. doi:10.1086/316343. S2CID 14298026.
  4. ^ a b Lianou, S.; et al. (November 2019). "Dust properties and star formation of approximately a thousand local galaxies". Astronomy & Astrophysics. 631: 19. arXiv:1906.02712. Bibcode:2019A&A...631A..38L. doi:10.1051/0004-6361/201834553. S2CID 174801441. A38.
  5. ^ a b Véron-Cetty, M.-P.; Véron, P. (2010). "A catalogue of quasars and active nuclei: 13th edition". Astronomy & Astrophysics. 518 (A10): A10. Bibcode:2010A&A...518A..10V. doi:10.1051/0004-6361/201014188.
  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. Retrieved 2024-03-24.
  7. ^ a b "NGC 4194". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2024-03-24.
  8. ^ Seligman, Courtney. "NGC Objects: NGC 4150 - 4199". Celestial Atlas. Retrieved 2024-04-01.
  9. ^ Demoulin, Marie-Helene (April 1969). "The Peculiar Galaxy NGC 4194". Astrophysical Journal. 156: 325. Bibcode:1969ApJ...156..325D. doi:10.1086/149967.
  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. Bibcode:2004AJ....127.1360W. doi:10.1086/382092.
  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. Bibcode:2003AAS...20311515H. doi:10.1086/497969.
  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. Bibcode:1985MNRAS.214...87J. doi:10.1093/mnras/214.2.87.
  13. ^ "Unknown extreme star formation discovered". Space Daily. 17 June 2015. Retrieved 2024-03-24.
  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. Bibcode:2012AJ....143...98W. doi:10.1088/0004-6256/143/4/98.
  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. arXiv:1404.1562. Bibcode:2014ApJ...787...85B. doi:10.1088/0004-637X/787/1/85.
  16. ^ "NGC 4194: A Black Hole in Medusa's Hair". Chandra Photo Album. March 11, 2009. Retrieved 2024-04-01.

Further reading

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