Messier 61

Messier 61 (also known as M61, NGC 4303, or the Swelling Spiral Galaxy) is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet.<ref name="SEDS">Template:Cite web</ref> Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.<ref name="atlas universe">Template:Cite web</ref>

Properties

M61 is one of the largest members of Virgo Cluster, and belongs to a smaller subgroup known as the S Cloud.<ref name="GOLDMine">Template:Cite web</ref><ref name="VirgoAtlas">Template:Cite web</ref> The morphological classification of SAB(rs)bc<ref name="ned" /> indicates a weakly-barred spiral (SAB) with the suggestion of a ring structure (rs) and moderate to loosely wound spiral arms.<ref name="Class"> Template:Cite journal</ref> It has an active galactic nucleus<ref name="Jiménez-Bailón2003"> Template:Cite journal</ref> and is classified as a starburst galaxy containing a massive nuclear star cluster with an estimated mass of 1 million solar masses (Template:Solar mass) and an age of 4 million years,<ref name="Colina2002">Template:Cite journal</ref> as well as a central candidate supermassive black hole weighing around Template:Solar mass.<ref name="Pastorini2007">Template:Cite journal</ref> It cohabits with an older massive star cluster as well as a likely older starburst.<ref name=Colina2002/> Evidence of significant star formation and active bright nebulae appears across M61's disk.<ref name="Koopmann2004"> Template:Cite journal</ref> Unlike most late-type spiral galaxies within the Virgo Cluster, M61 shows an unusual abundance of neutral hydrogen (H I).<ref name="Kenney1986"> Template:Cite journal</ref>

Eight supernovae have been observed in M61, making it one of the most prodigious galaxies for such cataclysmic events.<ref>Supernovae which have been observed in Messier catalog galaxies</ref><ref name="eps_super"> Template:Cite web</ref><ref name="SEDS" /> These include:

SN 1926A (Type II, mag. 14) was discovered by Max Wolf and Karl Wilhelm Reinmuth on 9 May 1926.<ref>Template:Cite web</ref><ref name="Boffi1999">Template:Cite journal</ref><ref>Template:Cite web</ref>
SN 1961I (Type II, mag. 13) was discovered by Milton Humason on 3 June 1961.<ref>Template:Cite web</ref><ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
SN 1964F (Type II, mag. 14) was discovered by Leonida Rosino on 30 June 1964.<ref>Template:Cite web</ref><ref>Template:Cite web</ref>
SN 1999gn (Type II, mag. 16) was discovered by Alessandro Dimai on 17 December 1999.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
SN 2006ov (Type II, mag. 14.9) was discovered by Kōichi Itagaki on 24 November 2006.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
SN 2008in (Type II, mag. 14.9) was discovered by Kōichi Itagaki on 26 December 2008.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
SN 2014dt (Type Ia-pec, mag. 13.6) was discovered by Kōichi Itagaki on 29 October 2014.<ref>Template:Cite journal</ref><ref>Template:Cite web</ref>
SN 2020jfo (Type II, mag. 16.01) was discovered by the Zwicky Transient Facility on 6 May 2020.<ref>Template:Cite web</ref>

M61 (with NGC 4301 in upper left) imaged by the Vera C. Rubin Observatory
Spiral galaxy Messier 61 is aligned face-on towards Earth.<ref>Template:Cite web</ref>
Messier 61 image using data from Hubble's Wide Field Camera 2
Amateur Image of Messier 61 Showing Supernova 2008in on April 16, 2009
Infrared image of M61 taken by the Spitzer Space Telescope
Messier 61 with SN2020jfo (Supernova) observed on May 15, 2020
M61 galaxy image that incorporates data from not only Hubble, but also the FORS camera at the European Southern Observatory’s Very Large Telescope