NGC 4194

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]

  1. ^ a b Cite error: The named reference Samsonyan_et_al_2016 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Ann_et_al_2015 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Falco_et_al_1999 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Lianou_et_al_2019 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Véron-Cetty_2010 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference ned was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference CSeligman was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Demoulin_1969 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Weistrup_et_al_2004 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Hancock_et_al_2003 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Joseph_Wright_1985 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SpaceDaily-2015-06-17 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Weistrop_et_al_2012 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Beck_et_al_2014 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Chandra was invoked but never defined (see the help page).