NGC 7318

{{short description|Pair of interacting galaxies in the constellation Pegasus}} {{Infobox Galaxy | name = NGC 7318 | epoch = J2000 | image = NGC_7318.jpg | caption = NGC 7318 imaged by the Hubble Space Telescope. 8-micrometre infrared light = red, H-alpha = green, visible red light = blue. NGC 7318b is the upper galaxy, NGC 7318a is the lower galaxy. | type = E2 pec / SB(s)bc pec | ra = {{RA|22|35|56.7}} / {{RA|22|35|58.4}} | dec = {{DEC|+33|57|56}} / {{DEC|+33|57|57}} | z = 6630 ± 23 / 5774 ± 24 km/s | dist_ly = 85 Mpc<ref name="duc"/> | appmag_v = 14.4 / 13.9 | size_v = 0.9{{prime}} × 0.9{{prime}} / 1.9{{prime}} × 1.2{{prime}} | constellation name = Pegasus | notes = Colliding galaxies | names = {{flatlist| * NGC 7318A / 7318B * UGC 12099 / 12100 * Arp 319 * PGC 69260 / 69263 * HCG 92D / 92B}} |references=<ref name="ned"/> }} thumb|The location of NGC 7318 (circled in blue) '''NGC 7318''' (also known as '''UGC 12099/UGC 12100''' or '''HCG 92d/b''') is a pair of colliding galaxies about 280 million light-years from Earth.<ref name="duc"/> They appear in the Constellation Pegasus and are members of Stephan's Quintet.<ref name="arp"/> They were discovered on 27 September 1873 by French astronomer Édouard Stephan.<ref name="selig">{{cite web | url = https://cseligman.com/text/atlas/ngc73.htm#7318 | title = New General Catalogue Objects: NGC{{nbsp}}7318 | last = Seligman | first = Courtney | website = Celestial Atlas | access-date = 28 August 2024 }}</ref>

The Spitzer Space Telescope revealed the presence of a large intergalactic shock wave, shown by an arc produced by NGC 7318b colliding with the group at ≥ 900 km/sec.<ref name="xu"/>

As NGC 7318b collides with NGC 7318a, atoms of hydrogen in the cluster's gas are heated by the shock wave, producing the green glow. The molecular hydrogen visible in the collision is one of the most turbulent forms known. This phenomenon was discovered by an international team of scientists of the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg. This collision can help provide a view into what happened in the early universe, around ten billion years ago.

== See also == * List of NGC objects (7001–7840)

==References== <references> <ref name="ned">{{cite web| title=NASA/IPAC Extragalactic Database| work=Results for NGC 7318a / 7318b | url=http://nedwww.ipac.caltech.edu/| access-date=2006-10-23 }}</ref>

<ref name="duc">{{cite journal |last1=Duc |first1=Pierre-Alain |last2=Cuillandre |first2=Jean-Charles |last3=Renaud |first3=Florent |title=Revisiting Stephan's Quintet with deep optical images |journal=Monthly Notices of the Royal Astronomical Society: Letters |date=March 2018 |volume=475 |issue=1 |pages=L40–L44 |doi=10.1093/mnrasl/sly004 |doi-access=free |arxiv=1712.07145 |bibcode=2018MNRAS.475L..40D }}</ref>

<ref name="arp">{{cite journal |last1=Arp |first1=Halton |title=Stephan's Quintet of Interacting Galaxies |journal=Astrophysical Journal |date=July 1973 |volume=183 |pages=411–440 |doi=10.1086/152236 |bibcode=1973ApJ...183..411A |url=https://ui.adsabs.harvard.edu/abs/1973ApJ...183..411A |access-date=9 February 2021}}</ref>

<ref name="xu">{{cite journal |last1=Xu |first1=C. K. |last2=Appleton |first2=P. N. |last3=Dopita |first3=M. |last4=Gao |first4=Y. |last5=Lu |first5=N. Y. |last6=Popescu |first6=C. |last7=Reach |first7=W. T. |last8=Sulentic |first8=J. |last9=Tuffs |first9=R. |last10=Yun |first10=M. |title=Spitzer Observations of Stephan's Quintet -- IGM Dust and Gas in a Multi-galaxy Collision |journal=The Second Annual Spitzer Science Center Conference: Infrared Diagnostics of Galaxy Evolution. ASP Conference Series |date=March 2008 |volume=381 |page=88 |bibcode=2008ASPC..381...88X |url=https://ui.adsabs.harvard.edu/abs/2008ASPC..381...88X|access-date=9 February 2021}}</ref> </references>

==External links== * {{commons category-inline}} * [https://web.archive.org/web/20031219121743/http://www.angelfire.com/id/jsredshift/h92ch.htm Hickson 92 in Pegasus] * [http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=NGC+7318A&NbIdent=1&Radius=10&Radius.unit=arcmin&CooFrame=FK5&CooEpoch=2000&CooEqui=2000&output.max=all&o.catall=on&output.mesdisp=N&Bibyear1=1983&Bibyear2=2006&Frame1=FK5&Frame2=FK4&Frame3=G&Equi1=2000.0&Equi2=1950.0&Equi3=2000.0&Epoch1=2000.0&Epoch2=1950.0&Epoch3=2000.0 '''SIMBAD''': VV 288 -- Interacting Galaxies] * [http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=NGC+7318B&NbIdent=1&Radius=10&Radius.unit=arcmin&CooFrame=FK5&CooEpoch=2000&CooEqui=2000&output.max=all&o.catall=on&output.mesdisp=N&Bibyear1=1983&Bibyear2=2006&Frame1=FK5&Frame2=FK4&Frame3=G&Equi1=2000.0&Equi2=1950.0&Equi3=2000.0&Epoch1=2000.0&Epoch2=1950.0&Epoch3=2000.0 '''SIMBAD''']: UGC 12100—Interacting Galaxies

Category:Barred spiral galaxies Category:Interacting galaxies Category:Elliptical galaxies Category:Peculiar galaxies Category:Stephan's Quintet Category:Pegasus (constellation) 7318 12099 069260 319 Category:Discoveries by Édouard Stephan Category:Astronomical objects discovered in 1873 Category:Galaxy mergers