View source for NGC 6946

{{Short description|Galaxy in the constellations Cepheus & Cygnus}}
{{Disputed|about the dubious-discuss in diameter|date=October 2022}}
{{Use dmy dates|date=March 2024}}
{{Infobox Galaxy
| name = [[New General Catalogue|NGC]] 6946
| image = Fireworks_Galaxy.jpg
| caption = An image of NGC 6946, the fireworks galaxy
| epoch = [[J2000]]
| type = SAB(rs)cd<ref name="ned"/>
| ra = {{RA|20|34|52.3}}<ref name="ned" />
| dec = {{DEC|+60|09|14}}<ref name="ned" />
| dist_ly =  25.2 ± 1.0 M[[light-year|ly]]<br/>{{nowrap|7.72± 0.32 M[[parsec|pc]])}}<ref name=Eldridgedistance>{{cite journal |last1=Eldridge |first1=J J |last2=Xiao |first2=Lin |date=2 March 2019 |title=The distance, supernova rate, and supernova progenitors of NGC 6946  |journal=Monthly Notices of the Royal Astronomical Society: Letters |volume=485 |issue=1 |pages=L58–L61 |doi=10.1093/mnrasl/slz030 |doi-access=free |arxiv=1903.00173 |bibcode=2019MNRAS.485L..58E |s2cid=118831398 }}</ref>
| size = {{convert|26.77|kpc|ly|sigfig=3|abbr=on|lk=on}}<br />(diameter; [[Galaxy#Isophotal diameter|25.0 mag/arcsec<sup>2</sup> B-band isophote]])<ref name="ned" /><ref name=RC3 />
| z = 0.000133<ref name=ned/>
| h_radial_v = {{nowrap|48 ± 2 [[Metre per second|km/s]]}}<ref name=ned/>
| appmag_v = +9.6<ref name="ned" />
| size_v = 16.0 x 11.2 [[Arcminute|arcmin]]<ref name="2MASS">{{Cite journal|title=The 2MASS Large Galaxy Atlas|author1=Jarrett, T. H.|author2=Chester, T.|author3=Cutri, R.|author4=Schneider, S. E.|author5=Huchra, J. P.|bibcode=2003AJ....125..525J|journal=The Astronomical Journal|issue=2|pages=525–554|year=2003|volume=125 |doi=10.1086/345794 |s2cid=117784410 |doi-access=free}}</ref>
| constellation name = [[Cepheus (constellation)|Cepheus]] and [[Cygnus (constellation)|Cygnus]]
| names = [[Uppsala General Catalogue|UGC]] 11597, [[Principal Galaxies Catalogue|PGC]] 65001, [[Atlas of Peculiar Galaxies|Arp]] 29,<ref name="ned" /> [[Caldwell catalogue|Caldwell]] 12}}

'''NGC 6946''', sometimes referred to as the '''Fireworks Galaxy''', is a [[grand design spiral galaxy|grand design]], face-on [[intermediate spiral galaxy]] with a small bright nucleus, whose location in the sky straddles the boundary between the [[Northern Celestial Hemisphere|northern]] [[constellation]]s of [[Cepheus (constellation)|Cepheus]] and [[Cygnus (constellation)|Cygnus]]. Its distance from Earth is about 25.2&nbsp;million [[light-year]]s or 7.72 [[parsecs|megaparsecs]],<ref name=Eldridgedistance /> similar to the distance of [[Messier 101|M101]] (NGC 5457) in the [[constellation]] [[Ursa Major]].<ref name="CAG1994"/>  Both were once considered to be part of the [[Local Group]],<ref name="SEDS2013"/> but are now known to be among the dozen bright [[Spiral galaxy|spiral galaxies]] near the [[Milky Way]] but beyond the confines of the [[Local Group]].<ref name="Efremov2017"/> NGC 6946 lies within the [[Virgo Supercluster]].<ref>{{Cite web|url=http://ned.ipac.caltech.edu/level5/Dev2/frames.html|title=Nearby Groups of Galaxies|website=ned.ipac.caltech.edu|access-date=2018-05-03}}</ref>

The [[galaxy]] was discovered by [[William Herschel]] on 9 September 1798. Based on an estimation by the Third Reference Catalogue of Bright Galaxies (RC3) in 1991, the galaxy has a [[Galaxy#Isophotal diameter|D<sub>25</sub> B-band isophotal diameter]] of {{convert|26.77|kpc|ly|sigfig=3|abbr=off|lk=on}}.<ref name="ned" /><ref name=RC3 /> It is heavily obscured by [[interstellar matter]] due to its location close to the [[galactic plane]] of the [[Milky Way]].<ref>{{Cite web|url=http://www.messier.seds.org/xtra/supp/o_NED.html#n6946|title=NED data for some important Non-Messier Galaxies}}</ref>  Due to its prodigious star formation it has been classified as an active [[starburst galaxy]].<ref name="Efremov2017"/> NGC 6946 has also been classified as a double-barred spiral galaxy, with the inner, smaller bar presumably responsible for funneling gas into its center.<ref>{{cite journal |last1=Schinnerer |first1=Eva |last2=et |first2=al |date=2006 |title=Molecular Gas Dynamics in NGC 6946: A Bar-driven Nuclear Starburst ''Caught in the Act''  |url=https://ui.adsabs.harvard.edu/abs/2006ApJ...649..181S |journal=The Astrophysical Journal |volume=649 |issue=1 |pages=181–200 |doi=10.1086/506265 |access-date=|arxiv=astro-ph/0605702 |bibcode=2006ApJ...649..181S |s2cid=14717998 }}</ref><ref>{{cite journal |last1=Eibensteiner |first1=Cosima |last2=et |first2=al |date=2022 |title=A 2-3 mm high-resolution molecular line survey towards the centre of the nearby spiral galaxy NGC 6946  |journal=Astronomy & Astrophysics |volume=659 |issue=A173 |pages= 37 |doi=10.1051/0004-6361/202142624 |arxiv=2201.02209 |bibcode=2022A&A...659A.173E |doi-access=free }}</ref>

Various unusual celestial objects have been observed within NGC 6946. This includes the so-called 'Red Ellipse' along one of the northern arms that looks like a super-bubble or very large supernova remnant, and which may have been formed by an open cluster containing massive stars. There are also two regions of unusual dark lanes of [[nebula|nebulosity]], while within the spiral arms several regions appear devoid of stars and gaseous hydrogen, some spanning up to two kiloparsecs across.<ref name="Efremov2017"/>{{Dubious|about the dubious-discuss in diameter|reason=Based on what distance to the galaxy?|date=October 2022}} A third peculiar object, discovered in 1967, is now known as "Hodge's Complex".<ref name="Hodge1967"/> This was once thought to be a young [[supergiant]] cluster, but in 2017 it was conjectured to be an interacting dwarf galaxy superimposed on NGC 6946.<ref name="Efremov2017"/>

==Supernovae==
Ten [[supernovae]] have been observed in NGC 6946 since 1917. For this reason, NGC 6946 has sometimes been referred to as the "Fireworks Galaxy".<ref name=gemini/><ref name=fireworks/> This is about ten times the rate observed in our [[Milky Way]] galaxy,<ref name=gemini2005/> even though the Milky Way has twice as many stars as NGC 6946.
* '''[[SN 1917A]]''' (type unknown, mag. 14) was discovered by American optician [[George Willis Ritchey]] on 19 July 1917.<ref>
{{cite journal|last1=Ritchie |first1=G. W. |title=Ritchie's Nova H. IV. 76 Cephei in N.G.C. 6946 |journal=Harvard College Observatory Bulletin |date=1917 |volume=641 |page=1 |bibcode=1917BHarO.641....1R}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1917A | url=https://www.wis-tns.org/object/1917A | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* [[SN 1939C]] (type unknown, mag. 14.4) was discovered by [[Fritz Zwicky]] on 17 July 1939.<ref>{{cite journal | url = http://www.cbat.eps.harvard.edu/IAUCs/IAUC0793.jpg | title = Supernova in NGC 6946 | last = Zwicky | first = Fritz | date = 2 September 1939 | journal = Central Bureau for Astronomical Telegrams | volume = 793 | pages = 1 | publisher = Observatory Copenhagen, [[International Astronomical Union|IAU]] | access-date = 16 August 2025}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1939C | url=https://www.wis-tns.org/object/1939C | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* '''SN 1948B''' ([[Type II supernova|Type{{nbsp}}II]], mag. 14.9) was discovered by [[Nicholas U. Mayall]] on 6 July 1948.<ref>{{cite journal |last1=Mayall |first1=N. U. |title=A Supernova in the Spiral Nebula NGC 6946 |journal=Publications of the Astronomical Society of the Pacific |date=1948 |volume=60 |issue=355 |page=266 |doi=10.1086/126065 |bibcode=1948PASP...60..266M}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1948B | url=https://www.wis-tns.org/object/1948B | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* '''SN 1968D''' (Type II, mag. 13.5) was discovered by [[Paul Wild (Swiss astronomer)|Paul Wild]] and Justus R. Dunlap on 29 February 1968.<ref name=IAUC2057>{{cite journal | url = http://www.cbat.eps.harvard.edu/IAUCs/IAUC2057.jpg | title = Supernova in NGC 6946 | last = Wild | first = P. | last2 = Dunlap | first2 = J. R. | date = 4 March 1968 | journal = Central Bureau for Astronomical Telegrams | volume = 2057 | 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 1968D | url=https://www.wis-tns.org/object/1968D | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref> A prediscovery photograph was also found which showed the supernova on 6 February with a magnitude of 13.5.{{r|IAUC2057}}
* '''SN 1969P''' (type unknown, mag. 13.9) was discovered by [[Leonida Rosino]] on 11 December 1969.<ref>{{cite journal | url = http://www.cbat.eps.harvard.edu/IAUCs/IAUC2305.jpg | title = New Supernova (1969) in NGC 6946? | last = Rosino | first = L. | date = 3 February 1971 | journal = Central Bureau for Astronomical Telegrams | volume = 2305 | pages = 1 | publisher = Smithsonian Astrophysical Observatory, [[International Astronomical Union|IAU]] | access-date = 16 August 2025 | bibcode=1971IAUC.2305....1R}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1969P | url=https://www.wis-tns.org/object/1969P | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* '''SN 1980K''' ([[Type II supernova#Light curves for Type II-L and Type II-P supernovae|Type{{nbsp}}II-L]], mag. 13) was discovered by Paul Wild on 28 October 1980.<ref>{{cite journal |last1=Wild |first1=P. |last2=Barbon |first2=R. |title=Supernova in NGC 6946 |journal=International Astronomical Union Circular |date=1980 |issue=3532 |page=1 |bibcode=1980IAUC.3532....1W | url = http://www.cbat.eps.harvard.edu/iauc/03500/03532.html#Item1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 1980K | url=https://www.wis-tns.org/object/1980K | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* '''SN 2002hh''' (Type II, mag. 16.5) was discovered by LOTOSS ([[Lick Observatory]] and [[Tenagra Observatories|Tenagra Observatory]] Supernova Searches) on 31 October 2002.<ref>{{cite journal |last1=Li |first1=W. |title=Supernova 2002hh in NGC 6946 |journal=International Astronomical Union Circular |date=2002 |issue=8005 |page=1 |bibcode=2002IAUC.8005....1L |  url = http://www.cbat.eps.harvard.edu/iauc/08000/08005.html#Item1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 2002hh | url=https://www.wis-tns.org/object/2002hh | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* '''[[SN 2004et]]''' ([[Type II supernova#Light curves for Type II-L and Type II-P supernovae|Type{{nbsp}}II-P]], mag. 12.8) was discovered by S. Moretti on 27 September 2004.<ref>{{cite journal|last1=Zwitter |first1=T. |last2=Munari |first2=U. |last3=Moretti |first3=S. |title=Supernova 2004et in NGC 6946 |journal=International Astronomical Union Circular |date=2004 |issue=8413 |page=1 |bibcode=2004IAUC.8413....1Z | url = http://www.cbat.eps.harvard.edu/iauc/08400/08413.html#Item1}}</ref> Images taken during the preceding days revealed that the supernova explosion occurred on 22 September. The progenitor of the supernova was identified on earlier images –– only the seventh time that such an event was directly identified with its host [[star]]. The [[red supergiant]] progenitor had an initial mass of about 15{{solar mass}} in an interacting [[binary system]] shared with a [[blue supergiant]].<ref name="Li2005" />
* '''SN 2008S''' ([[Type II supernova#Type IIn supernovae|Type{{nbsp}}IIn-pec]]/[[Luminous blue variable|LBV]], mag. 17.6) was discovered by Ron Arbour on 1 February 2008.<ref>{{cite journal |last1=Arbour |first1=R. |last2=Boles |first2=T. |title=Supernova 2008S in NGC 6946 |journal=Central Bureau Electronic Telegrams |date=2008 |issue=1234 |page=1 |bibcode=2008CBET.1234....1A | url = http://www.cbat.eps.harvard.edu/cbet/001200/CBET001234.txt}}</ref><ref>{{cite web | website=Transient Name Server | title=SN 2008S | url=https://www.wis-tns.org/object/2008S | publisher = [[International Astronomical Union|IAU]] | access-date=16 August 2025}}</ref>
* '''SN 2017eaw''' (Type II-P, mag. 12.8) was discovered by [[Patrick Wiggins (astronomer)|Patrick Wiggins]] on 14 May 2017.<ref name="Bishop-2017eaw"/><ref name=telegram1/> It was detected in the northwest region of the galaxy, and light curves obtained over the next 600 days showed that it was a Type II-P.<ref name=telegram2/><ref>{{Cite journal|last1=Buta|first1=Ronald J|last2=Keel|first2=William C|date=21 July 2019|title=BVRI photometry of the classic Type II-P supernova 2017eaw in NGC 6946: d 3 to d 594|url=https://academic.oup.com/mnras/article/487/1/832/5487895|journal=Monthly Notices of the Royal Astronomical Society|language=en|volume=487|issue=1|pages=832–844|doi=10.1093/mnras/stz1291|doi-access=free |issn=0035-8711|arxiv=1905.03084|bibcode=2019MNRAS.487..832B|s2cid=147703978}}</ref> The progenitor was determined to have been a [[Red supergiant star|red supergiant]], with a mass of around 15{{solar mass}}.<ref>{{Cite journal|last1=Szalai|first1=Tamás|last2=Vinkó|first2=József|last3=Könyves-Tóth|first3=Réka|last4=Nagy|first4=Andrea P.|last5=Bostroem|first5=K. Azalee|last6=Sárneczky|first6=Krisztián|last7=Brown|first7=Peter J.|last8=Pejcha|first8=Ondrej|last9=Bódi|first9=Attila|last10=Cseh|first10=Borbála|last11=Csörnyei|first11=Géza|date=29 April 2019|title=The Type II-P Supernova 2017eaw: From Explosion to the Nebular Phase|journal=The Astrophysical Journal|volume=876|issue=1|pages=19|doi=10.3847/1538-4357/ab12d0|arxiv=1903.09048|bibcode=2019ApJ...876...19S|s2cid=84842034|issn=1538-4357 |doi-access=free }}</ref><ref name=KF18/>

During 2009, a bright [[star]] within NGC 6946 flared up over several months to become over one million times as [[Brightness|bright]] as the [[Sun]]. Shortly thereafter it faded rapidly. Observations with the [[Hubble Space Telescope]] suggest that the star did not survive, although there remains some infrared emission from its position. This is thought to come from debris falling onto a [[black hole]] that formed when the star died. This potential black hole-forming star is designated [[N6946-BH1]].<ref name="Adams2016"/> The progenitor is believed to have been a [[Yellow hypergiant|yellow hypergiant star]].<ref>{{Cite journal|last=Humphreys|first=Roberta M.|date=31 October 2019|title=Comments on the Progenitor of NGC 6946-BH1|journal=Research Notes of the AAS|volume=3|issue=10|pages=164|doi=10.3847/2515-5172/ab5191|issn=2515-5172|arxiv=1911.02037|bibcode=2019RNAAS...3..164H|s2cid=207880492 |doi-access=free }}</ref>

As of 2017, more supernovae had been seen in NGC 6946 than in any other [[galaxy]],<ref name="Bishop-2017eaw">{{Cite web|url=https://rochesterastronomy.org/sn2017/sn2017eaw.html|title=Supernova 2017eaw in NGC 6946|quote=This is our most prolific galaxy with now 10 confirmed supernovae discovered.|first=David|last=Bishop|date=14 May 2017|access-date=2023-09-29}}</ref> a record that has since been surpassed by [[NGC 3690]].<ref name="MostProlific">{{Cite web | url=https://rochesterastronomy.org/snimages/sndupe.html | title=The most prolific galaxies | first=David | last=Bishop | date=27 August 2023 | access-date=2023-09-29}}</ref>

{| class="wikitable sortable" style="text-align: center; font-size: 0.9em;"
|+Supernovae in NGC 6946
! Designation
! [[apparent magnitude|Discovery magnitude]]
! Type
|-
| 1917A || 14 || II
|-
| 1939C || 14.4 || ?
|-
| 1948B || 14.9 || II
|-
| 1968D || 13.5 || II
|-
| 1969P || 13.9 || ?
|-
| 1980K || 13 || II-L
|-
| 2002hh || 16.5 || II
|-
| 2004et || 12.8 || II
|-
| 2008S || 17.6 || IIn-pec/LBV
|-
| 2017eaw || 12.8 || II-P
|}

==Nova images==
<gallery mode="packed" heights="200px">
File:NGC 6946 (Kitt Peak National Observatory) (2023-115).png|This image from the [[Kitt Peak National Observatory]] contextualizes the locations of [[SN 2004et|supernovae 2004et]] and [[SN 2017eaw|2017eaw]] within the [[galaxy]].

File:NBO 2017eaw.png|Images of [[SN 2017eaw|2017eaw]] in NGC 6946, taken between May and November 2017, as the supernova was slowly fading

File:Giant star N6946-BH1 before and after it vanished out of sight by imploding to form a black hole.jpg|Pair of [[Visible spectrum|visible-light]] and near-infrared photos from the [[Hubble Space Telescope]] showing the giant star [[N6946-BH1]] before and after it vanished out of sight by imploding to form a [[black hole]]

File:Dusty supernovae (MIRI, annotated) (dustysupernovae2).jpg|NASA/ESA/CSA [[James Webb Space Telescope]] image of NGC 6946, revealing large amounts of [[dust]] from the two supernovae [[SN 2004et]] and [[SN 2017eaw]]
</gallery>

==See also==
*[[IC 342]] – similar [[galaxy]] heavily obscured by [[Milky Way]] [[star]]s and [[Cosmic dust|dust]].
*[[List of galaxies]]

==References==
{{Reflist|refs=

<ref name="ned">{{cite web
| title=NASA/IPAC Extragalactic Database
| work=Results for NGC 6946
| url=http://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Obj_id&objid=48768&objname=1&img_stamp=YES&hconst=73.0&omegam=0.27&omegav=0.73&corr_z=1
| access-date=2022-10-29}}</ref>

<ref name=RC3>{{cite book | bibcode=1991rc3..book.....D | year=1991 | title=Third Reference Catalogue of Bright Galaxies | last1=De Vaucouleurs | first1=Gerard | last2=De Vaucouleurs | first2=Antoinette | last3=Corwin | first3=Herold G. | last4=Buta | first4=Ronald J. | last5=Paturel | first5=Georges | last6=Fouque | first6=Pascal }}</ref>

<ref name="CAG1994">{{cite book
|last1=Sandage|first1=A.
|last2=Bedke|first2=J.
|year=1994
|title=The Carnegie Atlas of Galaxies. Volume I
|publisher=Carnegie Institution of Washington
|bibcode=1994cag..book.....S}}</ref>

<ref name="Efremov2017">{{cite journal
|last1=Efremov|first1=Yu. N.
|title=Unusual Objects in the Spiral Galaxy NGC 6946
|journal=Open Astronomy
|year=2016
|volume=25
|issue=4
|pages=365–376
|bibcode=2016BaltA..25..369E|doi=10.1515/astro-2017-0255
|doi-access=free
}}</ref>

<!--<ref name=apod>{{Cite APOD|title=NGC 6946 : the Fireworks Galaxy|date=1 January 2011 |access-date=2 November 2017}}</ref> -->

<ref name="Hodge1967">{{cite journal
|last1=Hodge|first1=P.W.
|title=A Possible "Super-Supernova" Remnant in NGC 6946
|journal=Open Astronomy
|year=1967
|volume=79
|issue=466
|pages=466–470
|bibcode=1967PASP...79...29H
|doi=10.1515/astro-2017-0255|doi-access=free
}}</ref>

<ref name="Li2005">{{cite journal
|last1=Li|first1=W.
|last2=Van Dyk|first2=S.D.
|last3=Filippenko|first3=A.V
|last4=Cuillandre|first4=J.C.
|title=On the Progenitor of the Type II Supernova 2004et in NGC 6946
|journal=Publications of the Astronomical Society of the Pacific
|year=2005
|volume=117|issue=828
|pages=121–131
|bibcode=2005PASP..117..121L
|doi=10.1086/428278|arxiv=astro-ph/0412487|s2cid=17585230
}}</ref>

<ref name=telegram1>{{cite journal |last1=Dong |first1=Subo |last2=Stanek |first2=K. Z. |title=Confirmation of AT 2017eaw, a Probable Supernova in NGC 6946 |journal=The Astronomer's Telegram |date=2017 |volume=10372 |page=1 |bibcode=2017ATel10372....1D | url = http://www.astronomerstelegram.org/?read=10372}}</ref>

<ref name=telegram2>{{cite journal |last1=Xiang |first1=Danfeng |last2=Rui |first2=Liming |last3=Wang |first3=Xiaofeng |last4=Fu |first4=Jianning |last5=Xiao |first5=Feng |last6=Zhang |first6=Tianmeng |last7=Zhang |first7=Jujia |title=Spectroscopic Classification of SN 2017eaw in NGC 6946 as a Young Type IIP Supernova |journal=The Astronomer's Telegram |date=2017 |volume=10376 |page=1 |bibcode=2017ATel10376....1X | url=http://www.astronomerstelegram.org/?read=10376}}</ref>

<ref name=gemini>{{Cite news|url=http://www.gemini.edu/node/116
|title=Gemini Observatory Welcomes 2005 with Release of Galactic Fireworks Image
|last=Michaud|first=Peter
|date=1 January 2015
|newspaper=NASA
|access-date=2017-10-15}}</ref>

<ref name=fireworks>{{Cite news|url=https://www.nasa.gov/mission_pages/chandra/multimedia/fireworks-galaxy-ngc6946.html
|title=NGC 6946: The 'Fireworks Galaxy'
|last=Boen|first=Brooke
|date=20 May 2015
|newspaper=NASA
|access-date=2016-12-08}}</ref>

<ref name=gemini2005>{{citation
|title=Gemini Observatory Welcomes 2005 with Release of Galactic Fireworks Image
|date=1 January 2005
|work=Gemini Observatory
|url=http://www.gemini.edu/node/116
|access-date=2016-01-04}}</ref>

<ref name="Adams2016">{{cite journal
|last1=Adams|first1=S. M.
|last2=Kochanek|first2=C. S.
|last3=Gerke|first3=J. R.
|last4=Stanek|first4=K. Z.
|last5=Dai|first5=X.
|title=The search for failed supernovae with the Large Binocular Telescope: conformation of a disappearing star
|year=2017
|journal=Monthly Notices of the Royal Astronomical Society
|volume=468
|issue=4
|pages=4968–4981
|doi=10.1093/mnras/stx816
|doi-access=free
|arxiv=1609.01283v1|bibcode=2017MNRAS.468.4968A|s2cid=12919545
}}</ref>

<ref name="SEDS2013">{{cite web
|title=NGC 6946
|publisher=SEDS
|url=http://www.messier.seds.org/xtra/ngc/n6946.html
|access-date=2017-11-20}}</ref>

<ref name=KF18>{{cite journal 
| last1 = Kilpatrick
| first1 = Charles 
| last2 =  Foley
| first2 = Ryan
| title = The Dusty Progenitor Star of the Type II Supernova 2017eaw
| date = 5 September 2018
| journal = Monthly Notices of the Royal Astronomical Society
| volume = 481 
| issue = 2 
| pages = 2536–2547 
| doi = 10.1093/mnras/sty2435| doi-access = free 
| arxiv = 1806.00348
}}</ref>

}}

==External links==
{{commons category}}
* [http://messier.seds.org/xtra/ngc/n6946.html SEDS: Spiral Galaxy NGC 6946]
* [http://www.atlasoftheuniverse.com/galax200.html Atlas of the Universe]
* [http://astrobob.areavoices.com/2017/05/26/giant-star-becomes-a-black-hole-right-before-our-eyes N6946-BH1] {{Webarchive|url=https://web.archive.org/web/20170529203747/http://astrobob.areavoices.com/2017/05/26/giant-star-becomes-a-black-hole-right-before-our-eyes/ |date=29 May 2017 }} Giant Star Becomes A Black Hole Right Before Our Eyes!
* {{WikiSky}}
* [https://rochesterastronomy.org/sn2017/sn2017eaw.html List of observations and images of supernova SN 2017eaw]
* [https://www.researchgate.net/publication/310397794_Supernova_Rhythm A science-fiction story] by astronomer [[Andrew Fraknoi]] about NGC 6946

{{Astronomical catalogs|Arp=29|NGC=6946|C=12|UGC=11597|PGC=65001}}
{{Caldwell catalogue}}
{{NGC objects:6500-6999}}
{{Cygnus (constellation)}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{Sky|20|34|52.3|+|60|09|14|18000000}}

{{DEFAULTSORT:Ngc 6946}}
[[Category:Cepheus (constellation)]]
[[Category:Cygnus (constellation)]]
[[Category:Intermediate spiral galaxies]]
[[Category:NGC objects|6946]]
[[Category:UGC objects|11597]]
[[Category:Principal Galaxies Catalogue objects|65001]]
[[Category:Arp objects|029]]
[[Category:Caldwell objects|012b]]
[[Category:Astronomical objects discovered in 1798|17980909]]
[[Category:Virgo Supercluster]]