View source for Antennae Galaxies

{{Short description|Galaxies in the constellation Corvus}}
{{Infobox Galaxy
| name               = Antennae Galaxies
| image              = Antennae Galaxies reloaded.jpg
| caption            = [[Hubble Space Telescope]] image of NGC 4038 (top) and NGC 4039 (bottom)
| constellation name = [[Corvus (constellation)|Corvus]]<ref name="sinnott">{{cite book 
  | editor=R. W. Sinnott
  | title= The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer
  | date=1988
  | publisher=Sky Publishing Corporation and Cambridge University Press 
  | isbn=978-0-933346-51-2}}</ref>
| epoch              = [[J2000]]
| type               = SB(s)m pec<ref name="ned_ngc4038">{{cite web |url=https://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=NGC%204038&extend=no&hconst=67.74&omegam=0.3089&omegav=0.6911&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES |title=Detailed Information for Object NGC 4038 |work=[[NASA/IPAC Extragalactic Database]] |access-date=August 3, 2025}}</ref> / SA(s)m pecLINERSbrst<ref name="ned_ngc4039">{{cite web |url=https://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=NGC%204039&extend=no&hconst=67.74&omegam=0.3089&omegav=0.6911&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES |title=Detailed Information for Object NGC 4039 |work=[[NASA/IPAC Extragalactic Database]] |access-date=August 3, 2025}}</ref>
| ra                 = {{RA|12|01|53.0}}<ref name="ned_ngc4038" /> / {{RA|12|01|53.5}}<ref name="ned_ngc4039" />
| dec                = {{DEC|-18|52|03}}<ref name="ned_ngc4038" /> / {{DEC|-18|53|10}}<ref name="ned_ngc4039" />
| z                  = {{val|0.005417|0.000017}}<ref name="ned_ngc4038" /> / {{val|0.005474|0.000030}}<ref name="ned_ngc4039" />
| h_radial_v         = {{val|1624|5|ul=km/s|fmt=commas}}<ref name="ned_ngc4038" /> / {{val|1641|9|ul=km/s|fmt=commas}}<ref name="ned_ngc4039" />
| gal_v              = {{val|1467|8|ul=km/s|fmt=commas}}<ref name=vaucouleurs>{{cite journal|bibcode=1991RC3.9.C...0000d}}</ref><ref name="ned_ngc4038" /> / {{val|1484|11|ul=km/s|fmt=commas}}<ref name=vaucouleurs/><ref name="ned_ngc4039" />
| dist_ly            = {{cvt|22|+/-|3|Mpc|Mly|sigfig=4|abbr=on|lk=on|order=flip}}<ref name=schweizer>{{cite journal|last1=Schweizer |first1=François |last2=Burns |first2=Christopher R. |last3=Madore |first3=Barry F. |last4=Mager |first4=Violet A. |last5=Phillips |first5=M. M. |last6=Freedman |first6=Wendy L. |last7=Boldt |first7=Luis |last8=Contreras |first8=Carlos |last9=Folatelli |first9=Gaston |last10=González |first10=Sergio |last11=Hamuy |first11=Mario |last12=Krzeminski |first12=Wojtek |last13=Morrell |first13=Nidia I. |last14=Persson |first14=S. E. |last15=Roth |first15=Miguel R. |last16=Stritzinger |first16=Maximilian D. |title=A NEW DISTANCE TO THE ANTENNAE GALAXIES (NGC 4038/39) BASED ON THE TYPE Ia SUPERNOVA 2007sr |journal=The Astronomical Journal |date=2008 |volume=136 |issue=4 |pages=1482–1489 |doi=10.1088/0004-6256/136/4/1482 |arxiv=0807.3955 |bibcode=2008AJ....136.1482S }}</ref>
| appmag_v           = 11.2<ref name="ned_ngc4038" /> / 11.08<ref name="ned_ngc4039" />
| size_v             = {{Val|5.2|×|3.1|u=arcminute}}<ref name="ned_ngc4038" /> / {{Val|3.1|×|1.6|u=arcminute}}<ref name="ned_ngc4039" />
| size               = {{cvt|194.51|x|140.05|kpc|ly|sigfig=5|abbr=on|lk=on|disp=x|<br />(|)|order=flip}}<br />{{small|(''[[Galaxy#Isophotal diameter|diameter]]; 27.0 B-mag arcsec{{sup|−2}}'')}}<ref name="ned_ngc4038" />{{efn|name=Size correction|The quick-look major axis physical diameters given by NED of {{convert|194.51|x|140.05|kpc|ly|sigfig=3|abbr=off}} for NGC 4038 and {{convert|79.20|x|36.43|kpc|ly|sigfig=3|abbr=off}} for NGC 4039 were based on distance estimates of {{cvt|21.056|+/-|3.941|Mpc|e6ly|sigfig=4|abbr=off}} and {{cvt|20.943|+/-|4.484|Mpc|e6ly|sigfig=4|abbr=off}} using scales of 102.1 parsec/arcsec and 101.5 parsec/arcsec multiplied with given angular diameters.}} /<br />{{cvt|79.20|x|36.43|kpc|ly|sigfig=5|abbr=on|lk=on|disp=x|<br />(|)|order=flip}}<br />{{small|(''[[Galaxy#Isophotal diameter|diameter]]; 25.5 B-mag arcsec{{sup|−2}}'')}}<ref name="ned_ngc4039" />{{efn|name=Size correction}}
| notes              = [[Interacting galaxy|Interacting galaxies]]
| names              = Ringtail Galaxy,<ref name="ned_ngc4038" /><ref name="ned_ngc4039" /> [[New General Catalogue|NGC]] 4038 / 4039,<ref name="ned_ngc4038" /><ref name="ned_ngc4039" /> [[Principal Galaxies Catalogue|PGC]] 37967 / 37969,<ref name="ned_ngc4038" /><ref name="ned_ngc4039" /> [[Atlas of Peculiar Galaxies|Arp]] 244,<ref name="ned_ngc4038" /><ref name="ned_ngc4039" /> [[Caldwell catalogue|Caldwell]]&nbsp;60/61,<ref name="ned_ngc4038" /><ref name="ned_ngc4039" /> [[Uppsala General Catalogue Addendum|UGCA]] 264/265<ref name="ned_ngc4038" /><ref name="ned_ngc4039" />
}}

The '''Antennae Galaxies''' (also known as '''NGC 4038'''/'''NGC 4039''' or '''Caldwell 60'''/'''Caldwell 61''') are a pair of [[interacting galaxy|interacting galaxies]] in the [[constellation]] [[Corvus (constellation)|Corvus]]. They are currently going through a [[Starburst Galaxies|starburst]] phase, in which the collision of clouds of gas and dust, with entangled magnetic fields, causes rapid star formation. They were discovered by [[William Herschel]] in 1785.<ref name="universe-today">{{cite web
  | title=Corvus
  | work=Universe Today
  | url=http://www.universetoday.com/guide-to-space/constellations/corvus/
  | access-date=2006-12-07 }}</ref>

==General information==
[[File:Antennae Galaxies composite of ALMA and Hubble observations.jpg|thumb|Visible light Hubble image (blue) showing newly formed young stars overlaid with a radio image from the [[Atacama Large Millimeter Array]] showing the clouds of dense cold gas from which new stars form (red, pink and yellow)]]
[[File:NGC4038 Large 01.jpg|thumb|Streams of stars and dust, resembling insect antennae, being ejected from both galaxies. The name Antennae Galaxies comes from this resemblance.]]

The Antennae Galaxies are undergoing a galactic collision. These interacting galaxies are located 0.25° north of [[31 Crateris]] and 3.25° southwest of [[Gamma Corvi]].<ref name="o'meara">{{cite book |title=The Caldwell Objects |first=Stephen James |last=O'Meara |publisher=Cambridge University Press |year=2002 |pages=240–43 |isbn=978-0-521-82796-6 | url=https://books.google.com/books?id=3Hg6YHgx9nAC&pg=PA242}}</ref>

Located in the [[NGC 4038 group of galaxies|NGC 4038 group]] with five other galaxies, these two galaxies are known as the Antennae Galaxies because the two long tails of [[star]]s, [[interstellar medium|gas and dust]] ejected from the galaxies as a result of the collision resemble an [[insect|insect's]] [[antenna (biology)|antennae]]. 

The [[galaxy nucleus|nuclei]] of the two galaxies are joining to become one giant [[galaxy]]. Most galaxies probably undergo at least one significant collision in their lifetimes. This might be the future of our [[Milky Way]] with a 50 percent chance of [[Andromeda–Milky Way collision|colliding]] with the [[Andromeda Galaxy]].<ref name="sawala">{{Cite journal|title=No certainty of a Milky Way–Andromeda collision|first1=Till|last1=Sawala|first2=Jehanne|last2=Delhomelle|first3=Alis J.|last3=Deason|first4=Carlos S.|last4=Frenk|first5=Jenni|last5=Häkkinen|first6=Peter H.|last6=Johansson|first7=Atte|last7=Keitaanranta|first8=Alexander|last8=Rawlings|first9=Ruby|last9=Wright|display-authors=3|journal=[[Nature Astronomy]]|date=2 June 2025|volume=9 |issue=8 |pages=1206–1217 |doi=10.1038/s41550-025-02563-1|doi-access=free|arxiv=2408.00064 |bibcode=2025NatAs...9.1206S }}</ref> This collision and merger sequence (the [[Alar Toomre#Scientific accomplishments|Toomre sequence]]) for galaxy evolution was developed in part by successfully modeling the Antennae Galaxies' "antennae" in particular.

The Antennae galaxies also contain a relatively young collection of massive globular clusters that were possibly formed as a result of the collision between the two galaxies.<ref>{{Cite journal|title=van den Bergh, How Did Globular Clusters Form?|journal=The Astrophysical Journal|volume=559|issue=2|pages=L113–L114|doi=10.1086/323754|arxiv=astro-ph/0108298|year=2001|last1=Van Den Bergh|first1=Sidney|bibcode=2001ApJ...559L.113V|s2cid=44060272}}</ref> The young age of these clusters is in contrast to the average age of most known globular clusters (which are around 12 billion years old), with the formation of the globulars likely originating from shockwaves, generated by the collision of the galaxies, compressing large, massive molecular clouds. The densest regions of the collapsing and compressing clouds are believed to be the birthplace of the clusters.

NGC 4038 has many [[Cepheid variables]], around 53 of them.<ref> {{Cite simbad|title=NGC 4038|access-date=10 December 2024}} </ref>

==Distance==
Antennae Galaxies are widely accepted to be located at roughly {{convert|20|Mpc|e6ly|sigfig=1|abbr=off|lk=on}} from [[Earth]]. However, a 2008 study stated that they are less remote from the Milky Way than previously thought—at {{convert|13.3|+/-|1.0|Mpc|e6ly|sigfig=3|abbr=off}} based on photometry of the presumed [[tip of the red-giant branch]],<ref name=saviane>{{cite journal|last1=Saviane |first1=Ivo |last2=Momany |first2=Yazan |last3=Da Costa |first3=Gary S. |last4=Rich |first4=R. Michael |last5=Hibbard |first5=John E. |title=A New Red Giant–based Distance Modulus of 13.3 MPC to the Antennae Galaxies and Its Consequences1 |journal=The Astrophysical Journal |date=2008 |volume=678 |issue=1 |pages=179–186 |doi=10.1086/533408 |arxiv=0802.1045 |bibcode=2008ApJ...678..179S }}</ref><ref>{{cite web 
  | title= The Antennae Galaxies Found To Be Closer To Us 
  | work=Space Daily 
  | date=2008-05-12 
  | url=http://www.spacedaily.com/reports/The_Antennae_Galaxies_Found_To_Be_Closer_To_Us_999.html 
  | access-date=2008-06-30}}</ref> but an immediate paper later found three major issues regarding this estimate and considered it to be a probable misidentification of the tip of the red-giant branch.<ref name=schweizer/> An average distance estimate of {{convert|22|+/-|3|Mpc|e6ly|sigfig=3|abbr=off}} has been also calculated based on observations of the [[Type Ia supernova|Type Ia]] [[SN 2007sr]] in the southern tail using [[Las Campanas Observatory]], the large-scale flow model, reanalyzing [[Hubble Space Telescope]] data in the Archive with an improved method, finding a fainter tip of the red-giant branch.<ref name=schweizer/>

==Supernovae==
Four [[supernova]]e have been observed in NGC 4038.
* '''SN 1974E''' (type unknown, mag. 14) was discovered by [[List of minor planet discoverers#M. Lovas|Miklós Lovas]] on 21 March 1974.<ref>{{cite journal  | url = http://www.cbat.eps.harvard.edu/IAUCs/IAUC2653.jpg | title = Supernovae | last1 = Detre | first1 = L. | last2 = Lovas | first2 = M. | date = 26 March 1974 | journal = Central Bureau for Astronomical Telegrams | volume = 2653 | pages = 1 | publisher = Smithsonian Astrophysical Observatory, [[International Astronomical Union|IAU]] | access-date = 16 August 2025}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1974E | url=https://www.wis-tns.org/object/1974E |publisher = [[International Astronomical Union|IAU]] | access-date=17 August 2024}}</ref>
* '''[[SN 2004gt]]''' ([[Type Ib and Ic supernovae|Type Ic]], mag. 14.9) was discovered by Berto Monard on 12 December 2004.<ref>{{cite journal | bibcode=2004IAUC.8454....1M | title=Supernovae 2004gt, 2004gu, 2004gv | last1=Monard | first1=L. A. G. | last2=Quimby | first2=R. | last3=Gerardy| first3=C.| last4=Hoeflich| first4=P. | last5=Wheeler | first5=J. C. | last6=Chen | first6=Y. -T.| last7=Smith | first7=H. J. | last8=Bauer | first8=A. | journal=International Astronomical Union Circular | date=2004 | issue=8454 | page=1 | url = http://www.cbat.eps.harvard.edu/iauc/08400/08454.html#Item1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 2004gt | url=https://www.wis-tns.org/object/2004gt | publisher = [[International Astronomical Union|IAU]] | access-date=17 August 2024}}</ref>
* '''[[SN 2007sr]]''' ([[type Ia supernova|Type Ia]], mag. 12.9) was discovered by the [[Catalina Sky Survey]] on 18 December 2007.<ref>{{cite web | website=Transient Name Server | title=SN 2007sr | url=https://www.wis-tns.org/object/2007sr |publisher = [[International_Astronomical_Union|IAU]] | access-date=17 August 2024}}</ref><ref>{{cite journal | bibcode=2007CBET.1172....1D | title=Supernova 2007sr in NGC 4038 | last1=Drake | first1=A. J. | last2=Djorgovski | first2=S. G. | last3=Williams | first3=R. | last4=Mahabal | first4=A. | last5=Graham | first5=M. J. | last6=Christensen | first6=E. | last7=Beshore | first7=E. C.| last8=Larson | first8=S. M. | journal=Central Bureau Electronic Telegrams | date=2007 | issue=1172 | page=1 | url = http://www.cbat.eps.harvard.edu/iau/cbet/001100/CBET001172.txt}}</ref>
* '''SN 2013dk''' (Type Ic, mag. 15.8) was discovered by the CHASE Project (CHilean Automatic Supernovas sEarch) on 22 June 2013.<ref>{{cite journal | bibcode = 2013CBET.3565....1C| title = Supernova 2013dk in NGC 4038 = PSN J12015272-1852183| last1 = Carrasco| first1 = F.| last2 = Hamuy| first2 = M.| last3 = Antezana| first3 = R.| last4 = Gonzalez| first4 = L.| last5 = Cartier| first5 = R.| last6 = Forster| first6 = F.| last7 = Silva| first7 = S.| last8 = Ramirez| first8 = R.| last9 = Pignata| first9 = G.| last10 = Apostolovski| first10 = Y.| last11 = Paillas| first11 = E.| last12 = Varela| first12 = S.| last13 = Aros| first13 = F.| last14 = Conuel| first14 = B.| last15 = Folatelli| first15 = G.| last16 = Reichart| first16 = D. E.| last17 = Haislip| first17 = J. B.| last18 = Moore| first18 = J. P.| last19 = Lacluyze| first19 = A. P.| last20 = Vinko| first20 = J.| last21 = Marion| first21 = G. H.| last22 = Silverman| first22 = J. M.| last23 = Wheeler| first23 = J. C.| last24 = Szalai| first24 = T.| last25 = Quimby| first25 = R.| journal = Central Bureau Electronic Telegrams| date = 2013| issue = 3565| page = 1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 2013dk | url=https://www.wis-tns.org/object/2013dk |publisher = [[International Astronomical Union|IAU]] | access-date=17 August 2024}}</ref>
One [[supernova]] has been found in NGC 4039.
* '''SN 1921A''' (type unknown, mag. 16) was discovered by [[Edwin Hubble]] and [[John Charles Duncan]] in March 1921.<ref>{{cite web | website=Transient Name Server | title=SN 1921A | url=https://www.wis-tns.org/object/1921A |publisher = [[International Astronomical Union|IAU]] | access-date=17 August 2024}}</ref><ref>{{Cite simbad|title=SN 1921A|access-date=10 December 2024}}</ref>

==Timeline==
{{refimprove section|date=October 2020}}

About 1.2 billion years ago, the Antennae were two separate galaxies.<ref name="barneshernquist1992">{{cite journal
  | author=J. E. Barnes | author2=L. Hernquist
  | title=Dynamics of interacting galaxies
  | journal=Annual Review of Astronomy and Astrophysics
  | date=1992
  | volume=30
  | issue=1
  | pages=705–742
  | bibcode=1992ARA&A..30..705B  | doi=10.1146/annurev.aa.30.090192.003421
}}</ref> NGC 4038 was a [[barred spiral galaxy]] and NGC 4039 was a [[spiral galaxy]]. 900 million years ago, the Antennae began to approach one another, looking similar to [[NGC 2207 and IC 2163]]. 600 million years ago, the Antennae passed through each other, looking like the [[Mice Galaxies]]. 300 million years ago, the Antennae's stars began to be released from both galaxies. Today the two streamers of ejected stars extend far beyond the original galaxies, resulting in the antennae shape.<ref>{{cite web|url=https://nasa.gov/feature/goddard/caldwell-60-61|title=Caldwell 60/61|last=Henderson|first=Edward|date=2019-12-18|work=NASA|access-date=9 November 2021}}</ref>

Within 400 million years, the Antennae's nuclei will collide and become a single core with stars, gas, and dust around it.<ref>{{cite web|url=https://gizmodo.com/antennae-galaxies-are-slowly-colliding-in-beautiful-cha-5605407|title=Antennae Galaxies are slowly colliding in beautiful chaos of black holes|last=Wilkins|first=Alasdair|date=2010-08-05|work=Gizmodo|access-date=9 November 2021}}</ref> Observations and simulations of colliding galaxies (e.g., by [[Alar Toomre]]) suggest that the Antennae Galaxies will eventually form an [[elliptical galaxy]].<ref name="barneshernquist1992"/>{{page number needed|date=October 2020}}

==X-ray source==
Areas containing large amounts of [[neon]] (Ne), [[magnesium]] (Mg), and [[silicon]] (Si) were found when the [[Chandra X-ray Observatory]] analyzed the Antennae Galaxies. [[Heavy elements]] such as these are necessary in order for planets that may contain [[life]] (as we know it) to form. The clouds imaged contain 16 times as much magnesium and 24 times as much silicon as the [[Sun]].

==See also==
*[[Whirlpool Galaxy]]
*[[List of largest galaxies]]

==Notes==
{{notelist}}

==References==
{{reflist}}

==External links==
{{Commons category|Antennae Galaxies}}
*{{cite web|author=Astronomy Picture of the Day Archive|url=https://apod.nasa.gov/apod/ap170428.html|date=28 April 2017|title=Exploring the Antennae|access-date=2018-05-01}}
*[[Astronomy Picture of the Day]]: [http://antwrp.gsfc.nasa.gov/apod/ap971022.html The Antennae Galaxies (10/22/1997)]
*[[Astronomy Picture of the Day]]: [http://apod.nasa.gov/apod/ap100507.html The Antennae (05/07/2010)]
*[[Astronomy Picture of the Day]]: [http://apod.nasa.gov/apod/ap110429.html The Antennae (04/29/2011)]
*[[Astronomy Picture of the Day]]: [http://apod.nasa.gov/apod/ap150212.html The Antennae (02/12/2015)]
*[https://www.theregister.co.uk/2005/03/30/colliding_galaxies/ '''The Register''': Galactic prang fingered in star formation mystery]
*[http://www.spacetelescope.org/news/html/heic0615.html ESA/Hubble News Release]
*[http://www.spacetelescope.org/images/archive/freesearch/antennae+galaxies/viewall/1 ESA/Hubble images of Antennae Galaxies]
*[http://www.cita.utoronto.ca/~dubinski/antennae/antennae.html Animations of galactic collision producing antennae structures]
*{{WikiSky|1=NGC 4038}}
*[http://www.constellation-guide.com/antennae-galaxies/ Antennae Galaxies at Constellation Guide]

{{Sky|12|01|53|-|18|52|10|45000000}}
{{Caldwell catalogue}}
{{Ngc45}}
{{Corvus (constellation)}}
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[[Category:Barred spiral galaxies]]
[[Category:Unbarred spiral galaxies]]
[[Category:Peculiar galaxies]]
[[Category:Interacting galaxies]]
[[Category:NGC 4038 Group]]
[[Category:Corvus (constellation)]]
[[Category:NGC objects]]
[[Category:Principal Galaxies Catalogue objects|037967]]
[[Category:Arp objects|244]]
[[Category:Caldwell objects|060b]]
[[Category:Astronomical objects discovered in 1785]]
[[Category:UGCA objects]]
[[Category:Galaxy mergers]]