Editing Messier 100

{{Short description|Galaxy in the constellation Coma Berenices}}
{{Infobox galaxy
| name = [[Messier object|Messier]] 100
| image = Messier 100 — Grand Design Splendour.jpg
| caption = Galaxy Messier 100 imaged by [[ESO]], revealing complex spiral arm structure
| constellation name = [[Coma Berenices]]<ref name="sinnott1988">
{{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]]/[[Cambridge University Press]]
 |isbn=978-0-933346-51-2
}}</ref>
| epoch = [[J2000]]
| type = SAB(s)bc<ref name="ned">
{{cite web
 | website = NASA/IPAC Extragalactic Database
 | publisher = [[NASA]] and [[California Institute of Technology|Caltech]]
 | title = Results for object MESSIER 100
 | url = https://ned.ipac.caltech.edu/byname?objname=MESSIER+100
 | access-date = 2006-08-31
}}</ref>
| ra = {{RA|12|22|54.8616}}<ref name="ned" />
| dec = {{DEC|+15|49|17.886}}<ref name="ned" />
| dist_ly = 55 [[light-year|Mly]]<ref name="distance" />
| z = 0.005240<ref name="ned" />
| h_radial_v = {{val|1571|1|u=km/s|fmt=commas}}{{r|ned}}
| appmag_v = 9.3<ref>{{cite web
 |url=https://messier.seds.org/m/m100.html
 |title=Messier 100
 |access-date=30 April 2022
 |website=SEDS Messier Catalog}}</ref>
| size_v = {{Val|7.4|×|6.3|u=arcminute}}{{r|ned}}
| names = {{odlist | NGC= 4321 | UGC= 7450 | CGCG= 099-030 | MCG= +03-32-015 | IRAS= 12204+1605 | name= HOLM 387A | PGC= 40153}}
| size = ~{{convert|50.93|kpc|ly|abbr=on|lk=on|order=flip}} (estimated){{r|ned}}
| group_cluster=[[Virgo Cluster]]
}}

'''Messier 100''' (also known as '''NGC 4321''' or the '''Mirror Galaxy''') is a [[grand design spiral galaxy|grand design]] [[intermediate spiral galaxy]] in the southern part of the mildly [[celestial hemisphere|northern]] [[Coma Berenices]].<ref name="seds1">
{{cite web
 |title=Messier 100
 |work=SEDS: Spiral Galaxy M100 (NGC 4321), type Sc, in Coma Berenices
 |url=http://messier.seds.org/m/m100.html
 |access-date=2010-02-23
}}</ref> It is one of the brightest and largest galaxies in the [[Virgo Cluster]] and is approximately 55 million [[light-year]]s<ref name="distance">
{{cite web
 |title=Messier 100
 |url=http://www.hearstobservatory.com/messier_100.html
 |publisher=[[Hearst Observatory]]
 |access-date=2010-02-23
}}</ref> from [[Milky Way|our galaxy]], about 166,000 light-years in diameter. It was discovered by [[Pierre Méchain]] in 1781{{efn|On March 15}} and 29 days later seen again and entered by [[Charles Messier]] in [[Messier object|his catalogue]] "of nebulae and star clusters".<ref>
{{cite web
 |title=Catalog of Nebulae and Star Clusters
 |url=http://messier.seds.org/xtra/history/m-cat.html#M100
 |work=[[SEDS]]
 |access-date=2010-02-23}}</ref><ref name="seds2">
{{cite web
 |title=Messier 100
 |work=SEDS: Observations and Descriptions
 |url=http://messier.seds.org/Mdes/dm100.html
 |access-date=2010-02-23}}</ref> It was one of the first spiral galaxies to be discovered,<ref name="seds2" /> and was listed as one of fourteen [[Spiral galaxy|spiral nebulae]] by [[William Parsons, 3rd Earl of Rosse|Lord William Parsons of Rosse]] in 1850. [[NGC 4323]] and [[NGC 4328]] are [[satellite galaxy|satellite galaxies]] of M100; the former is connected with it by a bridge of luminous matter.<ref>
{{cite journal
 |author=S. di Serego Alighieri |display-authors=etal
 |date=2007
 |title=The HI content of Early-Type Galaxies from the ALFALFA survey I. Catalogued HI sources in the Virgo cluster
 |journal=[[Astronomy and Astrophysics]]
 |volume=474 |issue=3
 |arxiv=0709.2096
|doi = 10.1051/0004-6361:20078205 |bibcode = 2007A&A...474..851D |pages=851–855|s2cid=5332365
 }}</ref><ref>
{{cite simbad
 |title=NGC 4323
 |access-date=2010-02-23
}}</ref>

==Early observations==
[[File:Widefield View of M100.png|left|thumb|This is a widefield view of the galaxy, M100, directly left of the center of the picture - captured with an amateur telescope in 2025.]]
After the discovery of M100 by Méchain, [[Charles Messier]] made observations of the galaxy depicting it as a nebula without a [[star]]. He pointed out that it was difficult<ref name="seds2" /> to recognize the [[nebula]] because of its faintness. [[William Herschel]] was able to identify a bright cluster of stars<ref name="seds2" /> within the "nebula" during his observations. His son [[John Herschel|John]] expanded the findings in 1833. With the advent of better telescopes, John Herschel was able to see a round, brighter galaxy; however, he also mentioned that it was barely visible through clouds. [[William Henry Smyth]]<ref name="seds2" /> extended the studies of M100, detailing it as a pearly white nebula and pointing out diffuse spots.

==Star formation==
Messier 100 is considered a [[starburst galaxy]]<ref>
{{cite journal
 |author=Wozniak, H. |author2=Friedli, D. |author3=Martinet, L. |author4=Pfenniger, D.
 |date=1999
 |title=Double-barred starburst galaxies viewed by ISOCAM
 |journal=The Universe as Seen by ISO.
 |volume=427 |pages=989
 |bibcode = 1999ESASP.427..989W}}</ref> with the strongest [[star formation]] activity concentrated in its center, within a ring – actually two tightly wound [[spiral arm]]s attached to a small [[barred spiral galaxy|nuclear bar]] of radius: one thousand [[parsec]]s<ref>
{{cite journal
 |author=Sakamoto, Kazushi |display-authors=4 |author2=Okumura, Sachiko |author3=Minezaki, Takeo |author4=Kobayashi, Yukiyasu |author5=Wada, Keiichi
 |date=1995
 |title=Bar-Driven Gas Structure and Star Formation in the Center of M100
 |journal=The Astronomical Journal
 |volume=110 |issue=3 |page=2075
|doi =  10.1086/117670 |bibcode = 1995AJ....110.2075S}}</ref> – where [[star formation]] has been taking place for at least 500 million years in separate bursts.<ref>
{{cite journal
 |author=Allard, E. L. |author2=Knapen, J. H. |author3=Peletier, R. F. |author4=Sarzi, M.
 |date=2006
 |title=The star formation history and evolution of the circumnuclear region of M100
 |journal=[[Monthly Notices of the Royal Astronomical Society]]
 |volume=371 |issue=3 |pages=1087–1105
|doi =  10.1111/j.1365-2966.2006.10751.x |doi-access=free |bibcode = 2006MNRAS.371.1087A|arxiv = astro-ph/0606490 |s2cid=119370091 }}</ref>

As usual on spiral galaxies of the Virgo Cluster, in the rest of the disk both star formation<ref name="koopmannkenney2004">
{{cite journal
 | author=R. A. Koopmann |author2=J. D. P. Kenney
 | date=2004
 | title=Hα Morphologies and Environmental Effects in Virgo Cluster Spiral Galaxies
 | journal=[[Astrophysical Journal]]
 | volume=613
 | issue= 2 | pages=866–885
 | bibcode=2004ApJ...613..866K
 | doi= 10.1086/423191
|arxiv = astro-ph/0406243 |s2cid=17519217
 }}</ref> and [[neutral hydrogen]], of which M100 is deficient compared to isolated spiral galaxies of similar [[Hubble type]],<ref name=Chung2009>
{{cite journal
 |last1=Chung |first1=A. |display-authors=4 |last2=Van Gorkom |first2=J.H. |last3=Kenney |first3=J.F.P. |last4=Crowl |first4=Hugh |last5=Vollmer |first5=B.
 |date=2009
 |title=VLA Imaging of Virgo Spirals in Atomic Gas (VIVA). I. The Atlas and the H I Properties
 |journal=The Astronomical Journal
 |volume=138 |issue=6 |pages=1741–1816
 |bibcode=2009AJ....138.1741C
 |doi=10.1088/0004-6256/138/6/1741
|doi-access=free }}</ref> are truncated within the galaxy's disk, which is caused by interactions with the [[intracluster medium]] of Virgo.

==Supernovae==
[[File:Noirlab2019b.jpg|thumb|left|Supernova SN 2019ehk in M100 (Hubble)]]
Seven [[supernova]]e have been identified in M100:<ref name="seds1" />
* On 17 March 1901 [[Heber Doust Curtis|Heber Curtis]] discovered SN 1901B ([[Supernova#Type_I|type I]], mag. 15.6),<ref name="Ritchie">{{cite journal|bibcode=1917BHarO.642....1P |title=Ritchie's Nova |last1=Pickering |first1=E. C. |journal=Harvard College Observatory Bulletin |date=1917 |volume=642 |page=1}}</ref><ref name="seds1" /><ref>
{{cite simbad
 |title=SN 1901B
 |access-date=2010-02-23
}}</ref> at 110"W and 4"N from the galaxy's nucleus.<ref name=Curtis>{{cite journal | bibcode=1917LicOB...9..108C | title=Three novae in spiral nebulae | last1=Curtis | first1=Heber Doust | journal=Lick Observatory Bulletin | date=1917 | volume=300 | page=108 | doi=10.5479/ADS/bib/1917LicOB.9.108C }}</ref>
* Heber Curtis discovered SN 1914A (type unknown, mag. 15.7)<ref name="seds1" /><ref>
{{cite simbad
 |title=SN 1914A
 |access-date=2010-02-23
}}</ref> on 2 March 1914, at 24"E and 111"S from the galaxy's nucleus.<ref name=Ritchie /><ref name=Curtis />
* [[Milton L. Humason|Milton Humason]], with observations from early to mid 1960,{{efn|February 21 to June 17}} discovered SN 1959E (type I, mag. 17.5),<ref name="seds1" /><ref>
{{cite simbad
 |title=SN 1959E
 |access-date=2010-02-23
}}</ref> located 58"E and 21"S from the galaxy's nucleus.<ref>{{cite journal | author=Humason, M. L.; Gomes, Alercio M.; Kearns, C. E. | title=The 1960 Palomar Supernova Search | journal=Publications of the Astronomical Society of the Pacific | volume=73 | issue=432 | pages=175 | year=1961 | doi=10.1086/127650 | doi-access=free| bibcode=1961PASP...73..175H }}</ref>
* On 15 April 1979, amateur astronomer Gus Johnson discovered [[SN 1979C]], the first [[type II supernova]] found in the M100 galaxy. However, the star faded quickly, and later observations from x-ray to radio wavelengths revealed its remnant.<ref name="seds1" /><ref>
{{cite simbad
 |title=SN 1979C
 |access-date=2010-02-23
}}</ref><ref>{{cite journal | bibcode=1979IAUC.3348....1M | author=International Astronomical Union | title=IAU Circular 3348 | journal=International Astronomical Union Circulars | number=3348 | year=1979 | volume=3348 | page=1 | url=https://www.cbat.eps.harvard.edu/iauc/03300/03348.html | access-date=2024-11-25}}</ref>
* [[SN 2006X]] (type Ia, mag. 15.3) was discovered by Shoji Suzuki and Marco Migliardi on 7 February 2006, two weeks before fading to magnitude 17.<ref name="seds1" /><ref>
{{cite simbad
 |title=SN 2006X
 |access-date=2010-02-23
}}</ref><ref>{{cite journal|bibcode=2006IAUC.8667....1P |title=Supernovae 2006U, 2006V, 2006W, 2006X. (Lick Observatory Supernova Search) |last1=Ponticello |first1=N. J. |last2=Burket |first2=J. |last3=Li |first3=W. |last4=Chen |first4=Y. -T. |last5=Yang |first5=M. |last6=Lin |first6=C. -S. |last7=Soma |first7=M. |last8=Migliardi |first8=M. |last9=Dimai |first9=A. |journal=International Astronomical Union Circular |date=2006 |issue=8667 |page=1 | url = http://www.cbat.eps.harvard.edu/iauc/08600/08667.html}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2006X | url=https://www.wis-tns.org/object/2006X | publisher = [[International Astronomical Union|IAU]] | access-date=1 January 2025}}</ref>
* Jaroslaw Grzegorzek discovered SN 2019ehk ([[Type Ib and Ic supernovae|type{{nbsp}}Ib]], mag. 16.5) on 29 April 2019. The supernova reached a peak magnitude of approximately 15.8.<ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2019ehk | url=https://www.wis-tns.org/object/2019ehk | publisher = [[International Astronomical Union|IAU]] | access-date=25 November 2024}}</ref>
* [[SN 2020oi]] ([[Type Ib and Ic supernovae|type{{nbsp}}Ic]], mag. 17.28) was discovered by ''Automatic Learning for the Rapid Classification of Events'' (ALeRCE) on 7 January 2020.<ref name="seds1" /><ref>
{{cite simbad
 |title=SN 2020oi
 |access-date=2010-02-23
}}</ref><ref>{{cite web | website=Transient Name Server | title=SN{{nbsp}}2020oi | url=https://www.wis-tns.org/object/2020oi | publisher = [[International Astronomical Union|IAU]] | access-date=1 January 2025}}</ref>

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

==References and footnotes==
{{reflist|30em}}
{{notelist}}

==External links==
{{commons|Messier 100|Messier 100}}
* [http://messier.seds.org/m/m100.html SEDS: Spiral Galaxy 100]
* {{Sky-Map.org}}
* [http://www.spacetelescope.org/images/archive/freesearch/messier+100/viewall/1 ESA/Hubble Messier 100]
* [https://apod.nasa.gov/apod/ap150211.html NASA Astronomy Picture of the Day]

{{Portal bar|Astronomy|Stars|Outer space}}
{{Messier objects}}
{{NGC objects:4000-4499}}
{{Coma Berenices}}

{{Sky|12|22|54.8616|+|15|49|17.886|52500000}}

{{DEFAULTSORT:Messier 100}}
[[Category:Messier 100]]
[[Category:Intermediate spiral galaxies]]
[[Category:Coma Berenices]]
[[Category:Messier objects|100]]
[[Category:NGC objects]]
[[Category:Astronomical objects discovered in 1781|17810413]]
[[Category:Virgo Cluster]]
[[Category:Discoveries by Pierre Méchain]]
[[Category:UGC objects|07450]]
[[Category:MCG objects|+03-32-015]]
[[Category:IRAS catalogue objects|12204+1605]]
[[Category:Principal Galaxies Catalogue objects|040153]]