View source for NGC 3631

{{Short description|Galaxy in the constellation Ursa Major}}
{{Sky|11|21|02.8753|+|53|10|11.038}}
{{Infobox galaxy
| name = [[New General Catalogue|NGC]] 3631
| image =Hubble Looks at a Face-On Grand Spiral.jpg
| caption = NGC 3631 imaged by the [[Hubble Space Telescope]]
| constellation name = [[Ursa Major]]
| epoch = [[J2000]]
| type = SA(s)c <ref name="ned">{{cite web
  | title=NASA/IPAC Extragalactic Database
  | work=Results for NGC 3631
  | url=http://ned.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=NGC+3631
  | access-date=2016-01-18 }}</ref>
| ra = {{RA|11|21|02.8753}}<ref name="ned" />
| dec = {{DEC|+53|10|11.038}}<ref name="ned" />
| dist_ly = [[1 E23 m|33.7]] ± 17.7 [[light-year|Mly]] (10.3 ± 5.4 [[parsec|Mpc]])<ref name="ned" />
| z = 0.003839<ref name="ned" />
| h_radial_v = 	1151 ± 1 km/s<ref name="ned" />
| appmag_v = 10.1
| size = ~{{convert|17.39|kpc|ly|abbr=on|lk=on|order=flip}} (estimated)<ref name ="ned" />
| size_v = {{Val|5.0|×|4.8|u=arcminute}}<ref name="ned" />
| notes = 
| names = {{odlist | UGC= 6360 | Arp= 27 |MCG= +09-19-047 | VV= 363 | PGC= 34767}}<ref name="ned" />
}}
'''NGC 3631''' is a [[spiral galaxy]] located in the constellation [[Ursa Major]]. It is located at a distance of about 35 million [[light year]]s from Earth, which, given its apparent dimensions, means that NGC 3631 is about 60,000 light years across. It was discovered by [[William Herschel]] on April 14, 1789.<ref>[http://cseligman.com/text/atlas/ngc36.htm#3631 NGC 3631] cseligman.com</ref> It is a [[grand design spiral galaxy]] seen face on.

== Characteristics ==
NGC 3631 is a [[grand design spiral galaxy]] and features two principal [[spiral arm]]s, which begin near the center. The two main arms branch into secondary arms with lower surface brightness. The galaxy shows moderate-to-high star formation rate and bright [[HII region]]s are present in all the arms.<ref>Sandage, A., Bedke, J. (1994) ''The Carnegie Atlas of Galaxies. Volume I'', [[Carnegie Institution of Washington]]</ref> The star formation rate of the galaxy is 4.6 {{solar mass}} per year.<ref>{{cite journal|last1=Mineo|first1=S.|last2=Gilfanov|first2=M.|last3=Lehmer|first3=B. D.|last4=Morrison|first4=G. E.|last5=Sunyaev|first5=R.|title=X-ray emission from star-forming galaxies – III. Calibration of the LX-SFR relation up to redshift z ≈ 1.3|journal=Monthly Notices of the Royal Astronomical Society|date=11 January 2014|volume=437|issue=2|pages=1698–1707|doi=10.1093/mnras/stt1999|doi-access=free |arxiv=1207.2157|bibcode=2014MNRAS.437.1698M|s2cid=119190124}}</ref> [[Halton Arp]] observed "straight arms", and an "absorption tube crossing from inside to outside of southern arm" and added the galaxy to his [[Atlas of Peculiar Galaxies]].<ref name=Fridman2001>{{cite journal|last1=Fridman|first1=A. M.|last2=Khoruzhii|first2=O. V.|last3=Polyachenko|first3=E. V.|last4=Zasov|first4=A. V.|last5=Sil'Chenko|first5=O. K.|last6=Moiseev|first6=A. V.|last7=Burlak|first7=A. N.|last8=Afanasiev|first8=V. L.|last9=Dodonov|first9=S. N.|last10=Knapen|first10=J. H.|title=Gas motions in the plane of the spiral galaxy NGC 3631|journal=Monthly Notices of the Royal Astronomical Society|date=21 May 2001|volume=323|issue=3|pages=651–662|doi=10.1046/j.1365-8711.2001.04218.x|doi-access=free |arxiv=astro-ph/0012116|bibcode=2001MNRAS.323..651F|s2cid=119517678 }}</ref> At inclination of 17 degrees,<ref name=Fridman2001/> the galaxy is seen nearly face on.

The [[hydrogen line|HI imaging]] shows the spiral arms distinguished well and HI is also detected in most of the interarm regions. The atomic hydrogen is detected mostly within the limits of the optical disc but also extends one and a half times the radius of the optical disk. The hydrogen forms streaming motions near the spiral arms.<ref>{{cite journal|last1=Knapen|first1=J. H.|title=Atomic hydrogen in the spiral galaxy NGC 3631|journal=Monthly Notices of the Royal Astronomical Society|date=1 April 1997|volume=286|issue=2|pages=403–414|doi=10.1093/mnras/286.2.403|doi-access=free |arxiv=astro-ph/9612137|bibcode=1997MNRAS.286..403K|s2cid=13901223}}</ref> The gas features two anticyclonic and four cyclonic vortices, rotating with the spiral pattern. The anticyclones are caused by the differential rotation and the cyclones are the result of a high amplitude in the density wave. The centres of the anticyclones are located between the observed spiral arms and the cyclones lie close to the observed spirals.<ref name=Fridman2001/>

NGC 3631 has weak diffuse [[X-ray]] emission.<ref>{{cite journal|last1=Mineo|first1=S.|last2=Gilfanov|first2=M.|last3=Sunyaev|first3=R.|title=X-ray emission from star-forming galaxies - II. Hot interstellar medium|journal=Monthly Notices of the Royal Astronomical Society|date=1 November 2012|volume=426|issue=3|pages=1870–1883|doi=10.1111/j.1365-2966.2012.21831.x|doi-access=free |arxiv=1205.3715|bibcode=2012MNRAS.426.1870M|s2cid=85507925}}</ref> There are six candidates [[ultraluminous X-ray source]]s in disk of the galaxy, two which have an optical counterpart.<ref>{{cite journal|last1=Smith|first1=Beverly J.|last2=Swartz|first2=Douglas A.|last3=Miller|first3=Olivia|last4=Burleson|first4=Jacob A.|last5=Nowak|first5=Michael A.|last6=Struck|first6=Curtis|title=ChAInGeS: The Chandra Arp Interacting Galaxies Survey|journal=The Astronomical Journal|date=1 June 2012|volume=143|issue=6|pages=144|doi=10.1088/0004-6256/143/6/144|arxiv=1204.3194|bibcode=2012AJ....143..144S|s2cid=17427760}}</ref> The nucleus of the galaxy hosts a [[supermassive black hole]] with mass 10<sup>7.4</sup> (25 million) {{solar mass|link=yes}}, based on [[K band (infrared)|Ks]] bulge luminosity.<ref>{{cite journal|last1=Dong|first1=X. Y.|last2=De Robertis|first2=M. M.|title=Low-Luminosity Active Galaxies and Their Central Black Holes|journal=The Astronomical Journal|date=March 2006|volume=131|issue=3|pages=1236–1252|doi=10.1086/499334|arxiv=astro-ph/0510694|bibcode=2006AJ....131.1236D|s2cid=17630682}}</ref>

== Supernovae ==
Four [[supernova]]e have been discovered in NGC 3631:
* SN 1964A (type unknown, mag. 17) was discovered by [[Paul_Wild_(Swiss_astronomer)|Paul Wild]] on 4 February 1964.<ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1964A | url=https://www.wis-tns.org/object/1964A | publisher = [[International_Astronomical_Union|IAU]] | access-date=1 December 2024}}</ref>
* SN 1965L (type unknown, mag. 16) was discovered by Paul Wild on 25 September 1965.<ref>{{cite web
	| url = http://www.cbat.eps.harvard.edu/IAUCs/IAUC1930a.jpg
	| title = Circular No. 1930
	| last = Gingerich
	| first = Owen
	| date = 11 October 1965
	| website = Central Bureau for Astronomical Telegrams
	| publisher = Smithsonian Astrophysical Observatory
	| access-date = 1 December 2024
}}</ref> [Note: some sources incorrectly list the discovery date as 29 September 1965.]<ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1965L | url=https://www.wis-tns.org/object/1965L | publisher = [[International_Astronomical_Union|IAU]] | access-date=1 December 2024}}</ref>
* SN 1996bu ([[type II supernova|type II]], mag. 17.3) was discovered by [[Reiki Kushida]] on 14 November 1996.<ref>{{cite journal | bibcode = 1996IAUC.6505....1N| title = Supernova 1996bu in NGC 3631| last1 = Nakano| first1 = S.| last2 = Kushida| first2 = R.| last3 = Koshida| first3 = Y.| last4 = Garnavich| first4 = P.| last5 = Challis| first5 = P.| last6 = Kirshner| first6 = R.| last7 = Hergenrother| first7 = C.| last8 = Brown| first8 = W.| last9 = Marzke| first9 = R.| last10 = Odewahn| first10 = S.| journal = International Astronomical Union Circular| date = 1996| issue = 6505| page = 1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1996bu | url=https://www.wis-tns.org/object/1996bu | publisher = [[International_Astronomical_Union|IAU]] | access-date=1 December 2024}}</ref>
* SN 2016bau ([[Type_Ib_and_Ic_supernovae|type Ib]], mag. 17.8) was discovered by Ron Arbour on 13 March 2016, before it reached maximum light.<ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2016bau | url=https://www.wis-tns.org/object/2016bau | publisher = [[International_Astronomical_Union|IAU]] | access-date=1 December 2024}}</ref><ref>{{cite journal|title=Asiago spectroscopic and photometric observations of AT2016bau|url=http://www.astronomerstelegram.org/?read=8818|journal=The Astronomer's Telegram|volume=8818|pages=1|date=March 15, 2016|bibcode=2016ATel.8818....1G|last1=Granata|first1=V.|last2=Benetti|first2=S.|last3=Cappellaro|first3=E.|last4=Elias-Rosa|first4=N.|last5=Pastorello|first5=A.|last6=Tomasella|first6=L.|last7=Nascimbeni|first7=V.|last8=Ochner|first8=P.|last9=Tartaglia|first9=L.|last10=Terreran|first10=G.|last11=Turatto|first11=M.}}</ref> It was also observed in radio waves by the [[Karl G. Jansky Very Large Array|VLA]] as a [[radio astronomy|radio source]] with a flux density of 1.0 ± 0.03 mJy at 8.6&nbsp;GHz.<ref>{{cite journal|title=VLA observations of SN 2016bau of Type Ib in NGC 3631|url=http://www.astronomerstelegram.org/?read=8911|journal=The Astronomer's Telegram|volume=8911|pages=1|date=April 5, 2016|bibcode=2016ATel.8911....1K|last1=Kamble|first1=Atish|last2=Margutti|first2=Raffaella|last3=Alexander|first3=Kate|last4=Berger|first4=Edo|last5=Cantiello|first5=Matteo|last6=Challis|first6=Pete|last7=Chomiuk|first7=Laura|last8=Guidorzi|first8=Christiano|last9=Kirshner|first9=Robert|last10=Milisavljevic|first10=Danny|last11=De Mink|first11=Selma|author11-link=Selma de Mink|last12=Parrent|first12=Jerod|last13=Soderberg|first13=Alicia|author13-link=Alicia M. Soderberg|last14=Zapartas|first14=Emmanouil|last15=Zauderer|first15=Ashley}}</ref>

== Nearby galaxies ==
NGC 3631 forms a small group with [[NGC 3657]],<ref>{{cite journal|last1=Makarov|first1=Dmitry|last2=Karachentsev|first2=Igor|title=Galaxy groups and clouds in the local (z~ 0.01) Universe|journal=Monthly Notices of the Royal Astronomical Society|date=21 April 2011|volume=412|issue=4|pages=2498–2520|doi=10.1111/j.1365-2966.2010.18071.x|doi-access=free |bibcode=2011MNRAS.412.2498M|arxiv=1011.6277|s2cid=119194025}}</ref> which is part of the north [[Ursa Major Cluster|Ursa Major groups]], part of the [[Virgo Supercluster]].<ref>{{cite web|title=The Ursa Major Groups|url=http://www.atlasoftheuniverse.com/galgrps/uma.html|website=www.atlasoftheuniverse.com}}</ref>

== Gallery ==
<gallery>
NGC3631 - SDSS DR14.jpg|NGC 3631 (SDSS DR14)
NGC 3631 2MASS.jpg|NGC 3631 by [[2MASS]]
NGC3631-hst-R814G606B450.jpg|[[Hubble Space Telescope|HST]] image of NGC 3631.
NGC 3631 GALEX WikiSky.jpg|NGC 3631 by [[GALEX]]
</gallery>

== References ==
{{reflist}}

== External links ==
{{commonscat}}
{{wikiSky}}

{{Ursa Major}}
{{Ngc40}}

[[Category:Unbarred spiral galaxies]]
[[Category:Ursa Major]]
[[Category:Ursa Major Cluster]]
[[Category:NGC objects|3631]]
[[Category:UGC objects|06360]]
[[Category:Principal Galaxies Catalogue objects|34767]]
[[Category:Arp objects|027]]
[[Category:Astronomical objects discovered in 1789]]
[[Category:Discoveries by William Herschel]]