View source for NGC 520

{{Short description|Pair of colliding spiral galaxies in the constellation Pisces}}
{{Infobox galaxy
 | name       = [[New General Catalogue|NGC]] 520
 | image      = Hubble Interacting Galaxy NGC 520 (2008-04-24).jpg
 | caption    = NGC 520 imaged by the [[Hubble Space Telescope]]
 | constellation name = [[Pisces (constellation)|Pisces]]
 | epoch      = [[J2000]]
 | type       = Pec<ref name="ned"/>
 | ra         = {{RA|01|24|35.071}}<ref name=Skrutskie2006/>
 | dec        = {{DEC|+03|47|32.68}}<ref name=Skrutskie2006/>
 | z          = {{Val|0.007609|0.000010|fmt=commas}}<ref name=Crook2007/>
 | h_radial_v = {{Val|2281|3|u=km/s|fmt=commas}}<ref name=Crook2007/>
 | dist_ly    = {{Convert|32.2|Mpc|Mly|order=flip|abbr=on|lk=on}}<ref name=Cappellari2011/>
 | size       = ~{{convert|31.74|kpc|ly|abbr=on|lk=on|order=flip}} (estimated){{r|ned}}
 | appmag_v   = 12.2<ref name="ned" />
 | size_v     = {{Val|3.4|x|1.7|u=arcminute}}<ref name="ned" />
 | notes      = [[Interacting galaxies]]
 | names      = {{odlist | UGC= 966 | Arp= 157 | PGC= 5193 | VV= 231 | CGCG= 411-050 | MCG= +01-04-052 | IRAS= 01219+0331}}<ref name="ned" />
}}

'''NGC 520''', also known as the '''Flying Ghost''',<ref name="interstellarum">{{cite book|last1=Stoyan|first1=Ronald|last2=Schurig|first2=Stephan|title=interstellarum Deep Sky Atlas|publisher=Cambridge University Press; Oculum-Verlag GmbH|publication-place=Erlangen|date=2014|isbn=978-1-107-50338-0|oclc=920437579|url=http://www.deep-sky-atlas.com/}}</ref> is a pair of [[Interacting galaxies|colliding]] [[spiral galaxies]] about 105 million [[light-year]]s away in the [[constellation]] [[Pisces (constellation)|Pisces]].<ref name=ned-dist/> They were discovered by [[astronomer]] [[William Herschel]] on 13 December 1784.<ref name="cseligman"/>

[[Halton Arp]] called this the second-brightest very disturbed galaxy in the sky, and it is as bright in the infrared and radio bands as the [[Antennae Galaxies]]. Simulations indicate this object consists of two galactic disks that began interacting about 300&nbsp;million years ago. The system is still in an early stage of its merger, showing two separate velocity systems in the spectra, and two small tails. Two galactic nuclei have been detected,<ref name=Read2005/> and one is an [[H II region|H II nucleus]].<ref name=hoetal1997/>

[[File:NGC 520 (noirlab2328a).jpg|thumb|left|NGC 520 imaged by the [[Cerro Tololo Inter-American Observatory]]]]
The main galactic component is being viewed edge-on, making it fainter in the optical band. The secondary component is brighter but less massive than the main, and is located to the northwest. They are separated by a dark lane of dust. The region of the galaxies outside their nuclei experienced a period of increased star formation roughly around the time they began to interact.<ref name=Read2005/> Two [[dwarf galaxy|dwarf objects]] are located in the vicinity of this merging pair, and one of them, designated UGC957, is located in the northern [[tidal tail]] – it may be the result of the interaction.<ref name=Delgado-Donate2003/>

When viewed in the [[X-ray astronomy|X-ray]] band, the interacting galaxies appear around half as luminous as expected given their merger state. Analysis of the gas and molecular features suggests the secondary merger component is gas poor. Most of the star formation, therefore, took place in the gas-rich main component to the southeast. 15 X-ray sources are detected within the merger, with many of them displaying long-term variability. A large galactic wind is evident, being driven by the [[Starburst region|starburst activity]].<ref name=Read2005/>

== See also ==
* [[List of NGC objects (1–1000)]]

== References ==
{{Reflist|refs=

<ref name=Skrutskie2006>{{cite journal
 | title=The Two Micron All Sky Survey (2MASS)
 | display-authors=1 | last1=Skrutskie | first1=Michael F.
 | last2=Cutri | first2=Roc M. | last3=Stiening | first3=Rae
 | last4=Weinberg | first4=Martin D. | last5=Schneider | first5=Stephen E.
 | last6=Carpenter | first6=John M. | last7=Beichman | first7=Charles A.
 | last8=Capps | first8=Richard W. | last9=Chester | first9=Thomas
 | last10=Elias | first10=Jonathan H. | last11=Huchra | first11=John P.
 | last12=Liebert | first12=James W. | last13=Lonsdale | first13=Carol J.
 | last14=Monet | first14=David G. | last15=Price | first15=Stephan
 | last16=Seitzer | first16=Patrick | last17=Jarrett | first17=Thomas H.
 | last18=Kirkpatrick | first18=J. Davy | last19=Gizis | first19=John E.
 | last20=Howard | first20=Elizabeth V. | last21=Evans | first21=Tracey E.
 | last22=Fowler | first22=John W. | last23=Fullmer | first23=Linda
 | last24=Hurt | first24=Robert L. | last25=Light | first25=Robert M.
 | last26=Kopan | first26=Eugene L. | last27=Marsh | first27=Kenneth A.
 | last28=McCallon | first28=Howard L. | last29=Tam | first29=Robert
 | last30=Van Dyk | first30=Schuyler D. | last31=Wheelock | first31=Sherry L.
 | journal=The Astronomical Journal
 | date=1 February 2006 | volume=131 | issue=2 | pages=1163–1183
 | bibcode=2006AJ....131.1163S |issn=0004-6256
 | doi=10.1086/498708 | s2cid=18913331 | doi-access=free }}</ref>

<ref name=Crook2007>{{cite journal
 | title=Groups of Galaxies in the Two Micron All Sky Redshift Survey
 | last1=Crook | first1=Aidan C. | last2=Huchra | first2=John P.
 | last3=Martimbeau | first3=Nathalie | last4=Masters | first4=Karen L.
 | last5=Jarrett | first5=Tom | last6=Macri | first6=Lucas M.
 | journal=The Astrophysical Journal
 | volume=655 | issue=2 | pages=790–813 | date=February 2007
 | doi=10.1086/510201 | arxiv=astro-ph/0610732
 | bibcode=2007ApJ...655..790C | s2cid=11672751 }}</ref>

<ref name=Read2005>{{cite journal
 | title=A Chandra view of the anomalous half-merger NGC 520
 | last=Read | first=Andrew M.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=359 | issue=2 | pages=455–463 | date=May 2005
 | arxiv=astro-ph/0502483 | bibcode=2005MNRAS.359..455R 
 | doi=10.1111/j.1365-2966.2005.08958.x | doi-access=free | s2cid=15244648 }}</ref>

<ref name=Delgado-Donate2003>{{cite journal
 | title=Dwarfs after mergers? The case of NGC 520, NGC 772, Arp 141, NGC 3226/7, NGC 3656 and Arp 299
 | last1=Delgado-Donate | first1=E. J. | last2=Muñoz-Tuñón | first2=C.
 | last3=Deeg | first3=H. J. | last4=Iglesias-Páramo | first4=J.
 | display-authors=1 | journal=Astronomy and Astrophysics
 | volume=402 | pages=921–928 | date=May 2003
 | issue=3 | arxiv=astro-ph/0302492 | bibcode=2003A&A...402..921D 
 | doi=10.1051/0004-6361:20030211-1 | s2cid=5932040 }}</ref>

<ref name=Cappellari2011>{{cite journal
 | last1=Cappellari | first1=Michele | last2=Emsellem | first2=Eric
 | last3=Krajnović | first3=Davor | last4=McDermid | first4=Richard M.
 | last5=Scott | first5=Nicholas | last6=Verdoes Kleijn | first6=G. A.
 | last7=Young | first7=Lisa M. | last8=Alatalo | first8=Katherine
 | last9=Bacon | first9=R. | last10=Blitz | first10=Leo
 | last11=Bois | first11=Maxime | last12=Bournaud | first12=Frédéric
 | last13=((Bureau)) | first13=M. | last14=Davies | first14=Roger L.
 | last15=Davis | first15=Timothy A. | last16=de Zeeuw | first16=P. T.
 | last17=Duc | first17=Pierre-Alain | last18=Khochfar | first18=Sadegh
 | last19=Kuntschner | first19=Harald | last20=Lablanche | first20=Pierre-Yves
 | last21=Morganti | first21=Raffaella | last22=Naab | first22=Thorsten
 | last23=Oosterloo | first23=Tom | last24=Sarzi | first24=Marc
 | last25=Serra | first25=Paolo | last26=Weijmans | first26=Anne-Marie
 | title=The ATLAS<sup>3D</sup> project - I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria
 | display-authors=1 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=413 | issue=2 | pages=813–836 | date=May 2011
 | arxiv=1012.1551 | bibcode=2011MNRAS.413..813C
 | doi=10.1111/j.1365-2966.2010.18174.x | doi-access=free | s2cid=15391206 }}</ref>

<ref name=hoetal1997>{{cite journal
 | display-authors=1 | last1=Ho | first1=Luis C.
 | last2=Filippenko | first2=Alexei V. | last3=Sargent | first3=Wallace L. W.
 | title=A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
 | periodical=Astrophysical Journal Supplement
 | date=October 1997 | volume=112 | issue=2 | pages=315–390
 | doi=10.1086/313041 | arxiv=astro-ph/9704107
 | bibcode=1997ApJS..112..315H | s2cid=17086638 }}</ref>

<ref name="ned">{{cite web
 | website=NASA/IPAC Extragalactic Database
 | publisher = [[NASA]] and [[California_Institute_of_Technology|Caltech]]
 | title=Results for object NGC 0520
 | url=https://ned.ipac.caltech.edu/byname?objname=NGC+0520
 | access-date=2006-12-22 }}</ref>

<ref name=ned-dist>{{cite web
 | title=Distance Results for NGC 0520
 | work=NASA/IPAC Extragalactic Database
 | url=http://nedwww.ipac.caltech.edu/cgi-bin/nDistance?name=NGC+0520
 | access-date=2010-05-05}}</ref>

<ref name="cseligman">{{Cite web
 | url=http://cseligman.com/text/atlas/ngc5.htm#520
 | last = Seligman | first = Courtney
 | title=New General Catalog Objects: NGC 500 - 549
 | website=cseligman.com | language=en-US
 | access-date=2017-12-10 }}</ref>

}}

==External links==
{{commons category}}
* [http://www.kopernik.org/images/archive/n520.htm NGC 520, An Interacting pair of Spiral Galaxies]
* {{WikiSky}}

{{Ngc10}}
{{Catalogs|PGC=5193|UGC=966|NGC=520|Arp=157}}
{{Pisces (constellation)}}

{{Sky|01|24|35.1|+|03|47|33|100000000}}

{{DEFAULTSORT:NGC 0520}}

[[Category:Galaxy mergers]]
[[Category:Pisces (constellation)]]
[[Category:NGC objects|0520]]
[[Category:UGC objects|00966]]
[[Category:Principal Galaxies Catalogue objects|005193]]
[[Category:Arp objects|157]]
[[Category:Astronomical objects discovered in 1784|17841213]]
[[Category:Discoveries by William Herschel]]
[[Category:IRAS catalogue objects|01219+0331]]
[[Category:MCG objects|+01-04-052]]
[[Category:Peculiar galaxies]]