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Eyes Galaxies
NGC 4438 (top) and NGC 4435 (bottom) taken by the FORS2 instrument of the Very Large Telescope in 2011 (Credit: ESO)
Observation data (J2000.0 epoch)
Constellation	Virgo
Right ascension	12 27 45.6(J2000)
Declination	+13° 00' 31" (J2000)
Redshift	?
Distance	52 million ly
Apparent magnitude (V)	+10
Absolute magnitude (V)	12
Characteristics
Type	SB0/SAb
Apparent size (V)	?
Notable features	Interacting
Other designations
NGC 4435-8, Arp 120. VV 188

The Eyes Galaxies (NGC 4435-NGC 4438, also known as Arp 120) are a pair of galaxies about 52 million light-years away in the constellation Virgo. This galaxy takes its name from its ring structure which made it popular.

NGC 4435

NGC 4435 is a barred lenticular galaxy currently interacting with NGC 4438. Studies of the galaxy by the Spitzer Space Telescope revealed a relatively young (190 million years) stellar population within the galaxy's nucleus, whose origin may have arose through the interaction with NGC 4438 compressing gas and dust in that region, triggering a starburst. It also has a long tidal tail possibly caused by the interaction with the mentioned galaxy; however other studies suggest that tail is actually a galactic cirrus in the Milky Way totally unrelated to NGC 4435.

NGC 4438

NGC 4438 is the most curious interacting galaxy in the Virgo Cluster, due to the uncertainty surrounding the energy mechanism that heats the nuclear source; this energy mechanism may be a starburst region, or a black hole-powered active galactic nucleus (AGN). Both hypotheses are currently under investigation by astronomers.

This galaxy shows a highly distorted disk with long tidal tails due to interactions with other galaxies, that explain why sources differ to classify it as a lenticular or spiral galaxy. It also shows signs of a past extended -but modest- starburst, a considerable deficience of neutral hydrogen as well as a displacement of the components of its interstellar medium -atomic hydrogen, molecular hydrogen, interstellar dust, and hot gas- in the direction of NGC 4435, which suggests both a tidal interaction with the latter and the effects of ram-pressure stripping as NGC 4438 moves at high speed through Virgo's intracluster medium, increased by the encounter between both galaxies.

As interacting galaxies

While as described above there is evidence to suggest that the environmental damage to the interstellar medium of NGC 4438 may have been caused by an encounter (off-center collision) with NGC 4435, millions of years ago, the discover of several filaments of ionized gas that link NGC 4438 with its large neighbor the galaxy Messier 86 and the discover on the latter of gas and dust that may have been stripped of the former also shows a past interaction between the two systems, so given the high density of galaxies in the center of galaxy clusters it's possible the three galaxies mentioned (NGC 4435, NGC 4438, and M86) had interacted.

In popular culture

In the 2014 film Interstellar, "NGC 4438" along with specific observation data can be seen in Murphy Cooper (Jessica Chastain)'s notepad during the film's climactic sequence. As the presence of a supermassive black hole in the AGC of NGC 4438 is one of two leading theories, the galaxy is potentially that accessed by the wormhole in the film.

Gallery

• Image taken with the FORS2 instrument on the ESO's Very Large Telescope.
• NGC 4435 and dust ring around its nucleus by HST, 1.8′ view
• Hubble Space Telescope (HST) image of NGC 4438.
• The Virgo Cluster of galaxies (Burrell Schmidt telescope)
• NGC 4438 and NGC 4435 interacting galaxies. 32 inch Schulman telescope on Mt. Lemmon, AZ.

External links

• NGC 4438
• The Eyes Galaxies on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

References

1. Panuzzo, P.; Vega, O.; Bressan, A.; Buson, L.; et al. (2007). "The Star Formation History of the Virgo Early-Type Galaxy NGC 4435: The Spitzer Mid-Infrared View". The Astrophysical Journal. 656 (1): 206–216. arXiv:astro-ph/0610316. Bibcode:2007ApJ...656..206P. doi:10.1086/510147.
2. The Tail of NGC 4435
3. Cortese, L.; Bendo, G. J.; Isaak, K. G.; Davies, J. I.; et al. (2010). "Diffuse far-infrared and ultraviolet emission in the NGC 4435/4438 system: tidal stream or Galactic cirrus?". Monthly Notices of the Royal Astronomical Society: Letters. 403 (1): L26–L30. arXiv:1001.0980. Bibcode:2010MNRAS.403L..26C. doi:10.1111/j.1745-3933.2009.00808.x.{{cite journal}}: CS1 maint: unflagged free DOI (link)
4. Boselli, A.; Boissier, S.; Cortese, L.; Gil de Paz, A.; et al. (2005). "GALEX Ultraviolet Observations of the Interacting Galaxy NGC 4438 in the Virgo Cluster". The Astrophysical Journal. 623 (1): L13-L16. arXiv:astro-ph/0502040. Bibcode:2005ApJ...623L..13B. doi:10.1086/429377.
5. Vollmer, B.; Soida, M.; Chung, A.; Chemin, L.; et al. (2009). "Ram pressure stripping of the multiphase ISM in the Virgo cluster spiral galaxy NGC 4438". Astronomy & Astrophysics. 496 (3): 669–675. arXiv:0901.2770. Bibcode:2009A&A...496..669V. doi:10.1051/0004-6361/200811140.
6. Vollmer, B.; Braine, J.; Combes, F.; Sofue, Y. (2005). "New CO observations and simulations of the NGC 4438/NGC 4435 system. Interaction diagnostics of the Virgo cluster galaxy NGC 4438". Astronomy & Astrophysics. 441 (2): 473–489. Bibcode:2005A&A...441..473V. doi:10.1051/0004-6361:20041389.
7. Kenney, Jeffrey D. P.; Tal, Tomer; Crowl, Hugh H.; Feldmeier, John; et al. (2008). "A Spectacular Hα Complex in Virgo: Evidence for a Collision between M86 and NGC 4438 and Implications for the Collisional ISM Heating of Ellipticals". The Astrophysical Journal. 687 (2): L69-L94. arXiv:0810.0711. Bibcode:2008ApJ...687L..69K. doi:10.1086/593300.
8. Gomez, H. L.; Baes, M.; Cortese, L.; Smith, M. W. L.; et al. (2010). "A Spectacular Hα Complex in Virgo: Evidence for a Collision between M86 and NGC 4438 and Implications for the Collisional ISM Heating of Ellipticals". Astronomy and Astrophysics. 518. arXiv:1005.1597. Bibcode:2010A&A...518L..45G. doi:10.1051/0004-6361/201014530. L45.{{cite journal}}: CS1 maint: multiple names: authors list (link)
9. "Big Galaxy Collisions Can Stunt Star Formation" (Press release). National Optical Astronomy Observatory. October 7, 2008.
10. David Darling. "The Eyes (NGC 4435 and 4438)". Encyclopedia of Science.
11. "VLT Looks into The Eyes of the Virgin". ESO Photo Release. 24 August 2011. Retrieved 31 August 2011.

• Virgo (constellation)
• Virgo Cluster
• Interacting galaxies
• NGC objects
• Arp objects