Editing Messier 100 (section)

==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.