Messier Index/M74: Difference between revisions

| name = [[w:Messier object|Messier]] 74

| image = [[Imagefile:NGCMessier 62874 by HST.jpg|350px]]

<small>|caption = Messier 74. Credit: NASA/ESA/GMOS/HST.</small>

| epoch = [[w:J2000]]

| constellation name = [[w:Pisces (constellation)|Pisces]]<ref name="sinnott1988">{{cite book

| idisbn=ISBN 0-933-34651-4}}</ref>

| type = SA(s)c<ref name="ned">{{cite web/>

| dist_ly = 30 ± 6 [[w:light-year|Mly]]<ref name="hendryetal2005">{{cite journal/>

| names = [[w:New General Catalogue|NGC]] 628, [[w:Uppsala General Catalogue|UGC]] 1149, [[w:Principal Galaxies Catalogue|PGC]] 5974<ref name="ned" />

'''Messier 74''' (also known as ''NGC 628'') is a face-on [[w:spiral galaxy]] in the [[w:constellation]] [[w:Pisces (constellation)|Pisces]]. The galaxy contains two clearly-defined [[w:spiral arm]]s and is therefore used as an archetypal example of a [[grandw:Grand designDesign spiralSpiral galaxyGalaxy]].<ref name="carnegieatlas">{{cite book

| idisbn=ISBN 0-87279-667-1 }}</ref>. The galaxy's low surface brightness makes it the most difficult [[w:Messier Catalogue|Messier object]] for amateur astronomers to observe.<ref name="omeara1998">{{cite book

| idisbn=ISBN 0-521-55332-6}}</ref><ref name="jones1991">{{cite book

| edition= 2nd edition

| idisbn=ISBN 0-521-37079-5 }}</ref>. However, the relatively large angular size of the galaxy and the galaxy's face-on orientation make it an ideal object for professional astronomers who want to study [[w:spiral arm]] structure and [[w:Density wave theory|spiral density wave]]s.

| url=http://adsabs.harvard.edu/abs/2002IAUC.7810....1N}}</ref> and [[w:SN 2003gd]].<ref name="iauc8150">{{cite journal

| url=http://adsabs.harvard.edu/abs/2003IAUC.8150....2E}}</ref>.

SN 2002ap has attracted considerable attention because it is one of the few Type Ic supernovae (or [[w:hypernova]]e) observed within 10 [[w:parsec|Mpc]] in recent years.<ref name="mazzalietal2002">{{cite journal

| pages=L61-L65L61–L65

| url=http://adsabs.harvard.edu/abs/2002ApJ...572L..61M | doi=10.1086/341504
}}</ref><ref name="smarttetal2002">{{cite journal

| pages=L147-L151L147–L151

| url=http://adsabs.harvard.edu/abs/2002ApJ...572L.147S | doi=10.1086/341747
}}</ref><ref name="galyametal2002">{{cite journal

| pages=L73-L77L73–L77

| url=http://adsabs.harvard.edu/abs/2002MNRAS.332L..73G | doi=10.1046/j.1365-8711.2002.05535.x
}}</ref>. This supernovae has been used to test theories on the origins of similar Type Ic supernovae at hiigherhigher distances<ref name="smarttetal2002" /> and theories on the connection between supernovae and [[w:gamma ray burst]]s.<ref name="galyametal2002" />.

SN 2003gd is a Type II-P suvernovasupernova.<ref name="vandyketal2003">{{cite journal

| pages=1289-12951289–1295

| pages=L17-L20L17–L20

| url=http://adsabs.harvard.edu/abs/2005ApJ...632L..17S | doi=10.1086/497578
}}</ref>. This is one of the few supernovae in which such a reflection has been found. This reflection appears to be from dust in a sheet-like cloud that lies in front of the supernova, and it can be used to determine the composition of the interstellar dust.<ref name="sugerman2005" /><ref name="vandyketal2006">{{cite journal

| pages=351-357351–357

| url=http://adsabs.harvard.edu/abs/2006PASP..118..351V}}</ref>.

| idisbn=ISBN 0-521-35299-1}}</ref><ref name="garcia1993">{{cite journal

| pages=47-9047–90

| pages=178-194178–194

| url=http://adsabs.harvard.edu/abs/2000ApJ...543..178G | doi=10.1086/317070
}}</ref>. Although different group identification methods may consistently identify many of the same member galaxies in this group,<ref name="giuricinetal2002" />, the exact group membership is still uncertain.

| [[Imageimage:M74_3M74 3.6_56 5.8_88 8.0_microns_spitzer0 microns spitzer.png|thumb|250px|M74 as observed with the [[w:Spitzer Space Telescope]] as part of the [[w:Spitzer Infrared Nearby Galaxy Survey]]. The blue colors represent the 3.6 micrometre emission from stars. The green and red colors represent the 5.8 and 8.0 micrometre emission from [[w:polycyclic aromatic hydrocarbon]]s and possibly dust.]]

In [[w:March 22]], [[w:2005]], it was announced <ref name="chandra2005">[http://chandra.harvard.edu/photo/2005/m74/index.html Chandra :: Photo Album :: M74 :: 22 Mar 05<!-- Bot generated title -->]</ref> that the [[w:Chandra X-ray Observatory]] had observed an [[w:ultraluminous X-ray source]] (ULX) in M74, radiating more X-ray power than what a [[w:neutron star]] would in periodic intervals of around two hours. It has an estimated mass of around 10,000 [[w:Sun]]s. This is an indicator of an [[w:intermediate-mass black hole]]. This would be a rather uncommon class of black holes, somewhere in between in size of stellar black holes and the massive black holes theorized to reside in the center of many galaxies. Because of this, they are believed to not form not from single supernovae, but possibly from a number of lesser stellar black holes in a star cluster. The X-ray source is identified as CXOU J013651.1+154547.