View source for Messier 66

{{short description|Galaxy in the constellation Leo}}
{{Use dmy dates|date=March 2021}}
{{other uses|M66 (disambiguation){{!}}M66}}
{{Infobox Galaxy
 | name     = [[Messier object|Messier]] 66
 | image    = File:Phot-33c-03-fullres.jpg
 | caption  = A colour-composite image of M66
 | credit   = 
 | epoch    = [[J2000]]
 | type     = SAB(s)b<ref name=Ann2015/>
 | ra       = {{RA|11|20|15.026}}<ref name=Skrutskie2006/>
 | dec      = {{DEC|+12|59|28.64}}<ref name=Skrutskie2006/>
 | dist_ly  = {{Convert|9.6|Mpc|Mly|order=flip|abbr=on|lk=on}}<ref name=Tully2016/>
 | z        = {{Val|0.002425|0.000010}}<ref name=vaucoulerus1991/> ({{Val|696.3|12.7|u=km/s}})<ref name=Bosch2015/>
 | appmag_v = 8.9<ref name=vaucoulerus1991/>
 | size_v   = 9.1{{prime}} × 4.2{{prime}}<ref name="ned" />
 | size = 85,200 [[Light-Year|ly]] (26.12 [[kiloparsec|kpc]]) (estimated)<ref name = ned/>
 | constellation name = [[Leo (constellation)|Leo]]
 | notes    = Galaxy in the [[Leo Triplet]]
 | names    = [[Atlas of Peculiar Galaxies|Arp]] 16, [[New General Catalogue|NGC]] 3627, [[Principal Galaxies Catalogue|PGC]] 34695, [[Uppsala General Catalogue|UGC]] 6346<ref name="simbad"/>
}}

'''Messier 66''' or '''M66''', also known as '''NGC 3627''', is an [[intermediate spiral galaxy]] in the southern, [[celestial equator|equatorial]] half of [[Leo (constellation)|Leo]]. It was discovered by French astronomer [[Charles Messier]]<ref name=SEDS/> on 1 March 1780, who described it as "very long and very faint".<ref name=OMeara2014/> This galaxy is a member of a small group of galaxies that includes [[Messier 65|M65]] and [[NGC 3628]], known as the [[Leo Triplet]] or the M66 Group.<ref name=Adam2018/> M65 and M66 are a common object for [[Amateur astronomy|amateur astronomic]] observation, being separated by only {{Val|20|ul=arcminute}}.<ref name=OMeara2014/>

M66 has a [[Galaxy morphological classification|morphological classification]] of SABb,<ref name=Ann2015/> indicating a spiral shape with a weak [[Barred spiral galaxy|bar feature]] and loosely wound [[Spiral arm|arms]]. The [[isophote|isophotal]] axis ratio is 0.32, indicating that it is being viewed at an angle.<ref name=Ann2015/> M66 is receding from us with a heliocentric [[radial velocity]] of {{Val|696.3|12.7|u=km/s}}.<ref name=Bosch2015/> It lies 31<ref name=Tully2016/> million [[light-year]]s away and is about 95 thousand light-years across<ref>Per the [[small angle formula]]: 31 Mly × tan( 9.1{{prime}} ) = ~82 kly. diameter</ref> with striking [[dust lane]]s and bright star clusters along sweeping spiral arms.

Gravitational interaction from its past encounter with neighboring NGC 3628 has resulted in an extremely high central mass concentration; a high [[molecular mass|molecular]] to [[atomic mass]] ratio; and a resolved non-rotating clump of [[H I]] material apparently removed from one of the [[spiral arm]]s. The latter feature shows up visually as an extremely prominent and unusual spiral arm and dust lane structures as originally noted in the ''[[Atlas of Peculiar Galaxies]]''.<ref name="Zhangetal1993" />

==Supernovae==
Five [[supernova]]e have been observed in M66:
* [[SN 1973R]] ([[Type II supernova|Type&nbsp;II]], mag. 14.5) was discovered by [[Leonida Rosino]] on 19 December 1973.<ref>{{cite journal | url = http://www.cbat.eps.harvard.edu/IAUCs/IAUC2615.jpg | title = Supernova in NGC 3627 | last = Rosino | first = L. | date = 3 January 1974 | journal = Central Bureau for Astronomical Telegrams | volume = 2615 | pages = 1 | publisher = Smithsonian Astrophysical Observatory, [[International Astronomical Union|IAU]] | bibcode = 1974IAUC.2615....1R | access-date = 15 August 2025}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1973R | url=https://www.wis-tns.org/object/1973R | publisher = [[International Astronomical Union|IAU]] | access-date=3 December 2024}}</ref>
* [[SN 1989B]] ([[type Ia supernova|Type&nbsp;Ia]], mag. 13) was discovered by [[Robert Evans (astronomer)|Robert Evans]] on 30 January 1989.<ref>{{cite journal | bibcode=1989IAUC.4726....1E| title=Supernova 1989B in NGC 3627| last1=Evans| first1=R. O.| last2=McNaught| first2=R. H.| journal=International Astronomical Union Circular| date=1989| issue=4726| page=1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1989B | url=https://www.wis-tns.org/object/1989B | publisher = [[International Astronomical Union|IAU]] | access-date=3 December 2024}}</ref>
* [[SN 1997bs]] (type uncertain, mag. 17) was discovered by the [[Lick Observatory]] Supernova Search (LOSS) on 15 April 1997.<ref>{{cite journal | bibcode=1997IAUC.6627....1T| title=Supernova 1997bs in NGC 3627| last1=Treffers| first1=R. R.| last2=Peng| first2=C. Y.| last3=Filippenko| first3=A. V.| last4=Richmond| first4=M. W.| last5=Barth| first5=A. J.| last6=Gilbert| first6=A. M.| journal=International Astronomical Union Circular| date=1997| issue=6627| page=1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}1997bs | url=https://www.wis-tns.org/object/1997bs | publisher = [[International Astronomical Union|IAU]] | access-date=3 December 2024}}</ref> This event was initially classified as a Type IIn supernova, but later analysis suggests that it is instead either a [[luminous blue variable]],<ref>{{cite journal |last1=Van Dyk |first1=Schuyler D. |last2=Peng |first2=Chien Y. |last3=King |first3=Jennifer Y. |last4=Filippenko |first4=Alexei V. |last5=Richards |first5=R. R. |last6=Li |first6=Weidong |last7=Richmond |first7=Michael W. |title=SN 1997bs in M66: Another Extragalactic η Carinae Analog? |journal=Publications of the Astronomical Society of the Pacific |volume=112 |issue=778 |pages=1532–1541 |year=2000 |doi=10.1086/317727|arxiv=astro-ph/0009027 |bibcode=2000PASP..112.1532V }}</ref> a [[Calcium-rich supernova|"gap" transient]],<ref>{{cite journal | doi=10.1093/mnras/stab1938 | doi-access=free | title=A systematic reclassification of Type IIn supernovae | date=2021 | last1=Ransome | first1=C. L. | last2=Habergham-Mawson | first2=S. M. | last3=Darnley | first3=M. J. | last4=James | first4=P. A. | last5=Filippenko | first5=A. V. | last6=Schlegel | first6=E. M. | journal=Monthly Notices of the Royal Astronomical Society | volume=506 | issue=4 | pages=4715–4734 | arxiv=2107.02179 }}</ref> or a [[luminous red nova]].<ref>{{cite arXiv |eprint=2504.14592 |last1=Reguitti |first1=A. |last2=Pastorello |first2=A. |last3=Valerin |first3=G. |title=The fate of the progenitors of Luminous Red Novae: Infrared detection of LRNe years after the outburst |date=2025 |class=astro-ph.SR }}</ref>
* [[SN 2009hd]] (Type II, mag. 15.8) was discovered by Libert (Berto) Monard on 2 July 2009.<ref>{{cite journal | bibcode=2009CBET.1867....1M| title=Supernova 2009hd in M66| last1=Monard| first1=L. A. G.| journal=Central Bureau Electronic Telegrams| date=2009| issue=1867| page=1}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2009hd | url=https://www.wis-tns.org/object/2009hd | publisher = [[International Astronomical Union|IAU]] | access-date=3 December 2024}}</ref>
* [[SN 2016cok]] (Type IIP, mag. 16.6) was discovered by the [[All Sky Automated Survey]] for Supernovae on 28 May 2016.<ref name=Sutaria2016/><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2016cok | url=https://www.wis-tns.org/object/2016cok | publisher = [[International Astronomical Union|IAU]] | access-date=2 December 2024}}</ref><ref name=":0">{{Cite web|url=https://www.smithsonianmag.com/smart-news/spy-two-supernovae-june-night-sky-180959400/|title=Spy Two Supernovae in June's Night Sky|last=Lewis|first=Danny|website=Smithsonian|language=en|access-date=2019-11-22}}</ref>

==Gallery==
<gallery widths="220" heights="220">
File:Sig05-016.jpg|alt=A "False Color" Version of Messier 66 by the SST (Spitzer Space Telescope)|Infrared false color view of M66 from the [[Spitzer Space Telescope]] 
File:Infrared_false_color_view_of_M66_from_the_Jamess_Webb_Telescope.jpg|alt=A "False Color" Version of Messier 66 by the James Webb Space Telescope|Infrared false color view of M66 from the [[James Webb Space Telescope]] 
File:Messier 066 2MASS.jpg|Messier 66 by [[2MASS]]
File:Messier 66 - NGC 3627 - GALEX.png|An [[ultraviolet]] image of Messier 66 by [[GALEX]]
</gallery>

==See also==
* [[List of Messier objects]]

==References==
{{reflist|refs=

<ref name="simbad">{{cite simbad | title=NGC 3627 | access-date=2018-12-02 }}</ref>

<ref name=SEDS>{{citation
 | date=15 June 2016 | postscript=.
 | first1=Hartmut | last1=Frommert
 | first2=Christine | last2=Kronberg
 | url=http://messier.seds.org/m/m066.html
 | title=Spiral Galaxy M66 | access-date=2018-12-03 }}</ref>

<ref name=OMeara2014>{{citation
 | title=Deep-Sky Companions: The Messier Objects
 | first1=Stephen James | last1=O'Meara
 | publisher=Cambridge University Press
 | year=2014 | isbn=978-1107018372 | page=248
 | url=https://books.google.com/books?id=fDQZAwAAQBAJ&pg=PA248 }} It is recorded as discovered by Pierre Méchain, but apparently this is an error.</ref>

<ref name=Bosch2015>{{citation
 | title=Hunting for Supermassive Black Holes in Nearby Galaxies With the Hobby-Eberly Telescope
 | last1=van den Bosch | first1=Remco C. E. | last2=Gebhardt | first2=Karl
 | last3=Gültekin | first3=Kayhan | last4=Yıldırım | first4=Akin
 | last5=Walsh | first5=Jonelle L. | display-authors=1
 | journal=The Astrophysical Journal Supplement Series
 | volume=218 | issue=1 | id=10 | pages=13 | date=May 2015
 | doi=10.1088/0067-0049/218/1/10 | bibcode=2015ApJS..218...10V
 | arxiv=1502.00632 | s2cid=117876537 | postscript=. }}</ref>

<ref name=Sutaria2016>{{citation
 | title=No X-ray detection of SN2016cok by Swift XRT
 | last1=Sutaria | first1=Firoza | last2=Ray | first2=Alak
 | journal=The Astronomer's Telegram
 | volume=9189 | pages=1 | date=June 2016 | postscript=.
 | bibcode=2016ATel.9189....1S }}</ref>

<ref name=Adam2018>{{citation
 | title=Imaging the Messier Objects Remotely from Your Laptop
 | series=The Patrick Moore Practical Astronomy Series
 | first1=Len | last1=Adam | year=2018
 | publisher=Springer | isbn=978-3319653853 | page=290
 | url=https://books.google.com/books?id=7nNUDwAAQBAJ&pg=PA290 | bibcode=2018imor.book.....A
 }}</ref>

<ref name=Ann2015>{{citation
 | title=A Catalog of Visually Classified Galaxies in the Local (z ~ 0.01) Universe
 | last1=Ann | first1=H. B. | last2=Seo | first2=Mira
 | last3=Ha | first3=D. K. | display-authors=1
 | journal=The Astrophysical Journal Supplement Series
 | volume=217 | issue=2 | pages=27–49 | date=2015
 | bibcode=2015ApJS..217...27A | doi=10.1088/0067-0049/217/2/27
 | arxiv=1502.03545 | s2cid=119253507 | postscript=. }}</ref>

<ref name=Skrutskie2006>{{cite journal |doi=10.1086/498708 |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. |title=The Two Micron All Sky Survey (2MASS) |journal=The Astronomical Journal |date=1 February 2006 |volume=131 |issue=2 |pages=1163–1183 |bibcode=2006AJ....131.1163S |s2cid=18913331 |issn=0004-6256 |doi-access=free }}</ref>

<ref name=Tully2016>{{citation
 | last1=Tully | first1=R. Brent | last2=Courtois | first2=Hélène M.
 | last3=Sorce | first3=Jenny G. | display-authors=1
 | title=Cosmicflows-3 | journal=The Astronomical Journal
 | volume=152 | issue=2 | id=50 | pages=21 | date=August 2016
 | doi=10.3847/0004-6256/152/2/50  | bibcode=2016AJ....152...50T
 | arxiv=1605.01765 | s2cid=250737862 | postscript=. | doi-access=free }}</ref>

<ref name=vaucoulerus1991>{{citation | postscript=.
 | last1=de Vaucouleurs | first1=G. | last2=de Vaucouleurs | first2=A.
 | last3=Corwin | first3=H. G. Jr. | last4=Buta | first4=R. J.
 | last5=Paturel | first5=G. | last6=Fouque | first6=P.
 | title=Third reference catalogue of bright galaxies
 | version=9 | display-authors=1 | date=1991
 | publisher=[[Springer-Verlag]] | location=New York }}</ref>

<ref name="ned">{{citation 
 | title=NASA/IPAC Extragalactic Database
 | work=Results for NGC 3627 | postscript=.
 | url=http://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=m66&extend=no&hconst=73&omegam=0.27&omegav=0.73&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
 | access-date=2006-08-31 }}</ref>

<ref name=Zhangetal1993>{{citation 
 | last1=Zhang | first1=Xiaolei | last2=Wright | first2=Melvyn
 | last3=Alexander | first3=Paul | display-authors=1
 | title=High-Resolution CO and H i Observations of the Interacting Galaxy NGC 3627
 | journal=[[Astrophysical Journal]] | postscript=.
 | volume=418 | page=100 | date=1993
 | bibcode=1993ApJ...418..100Z | doi=10.1086/173374 | doi-access=free }}</ref>

}}

==External links==
{{commons category}}
* [http://ryutao.main.jp/english/st2k_m66_m300.html Spiral Galaxy M66]
* [[Astronomy Picture of the Day]] – [https://apod.nasa.gov/apod/ap100413.html Unusual Spiral Galaxy M66 from Hubble] – 2010 April 13
* [https://apod.nasa.gov/apod/ap240613.html Messier 66 Close Up], [[APOD]] June 13, 2024
* {{cite web|title=M66 – Spiral Galaxy|url=http://www.deepskyvideos.com/videos/messier/M66_spiral_galaxy.html|work=Deep Sky Videos|publisher=[[Brady Haran]]|author=Merrifield, Mike|author2=Szymanek, Nik |author-link2=Nik Szymanek }}{{WikiSky}}

{{Sky|11|20|15.0|+|12|59|30|36000000}}
{{Portal bar|Astronomy|Stars|Outer space}}
{{Messier objects}}
{{Ngc40}}

[[Category:Intermediate spiral galaxies]]
[[Category:Leo Triplet|Messier 066]]
[[Category:Leo (constellation)|Messier 066]]
[[Category:Messier objects|066]]
[[Category:NGC objects|Messier 066]]
[[Category:UGC objects|06346]]
[[Category:Principal Galaxies Catalogue objects|34695]]
[[Category:Arp objects|016]]
[[Category:Astronomical objects discovered in 1780]]
[[Category:Articles containing video clips]]
[[Category:Discoveries by Charles Messier]]