பயனர்:TNSE MANI VNR/மணல்தொட்டி: திருத்தங்களுக்கு இடையிலான வேறுபாடு
உள்ளடக்கம் நீக்கப்பட்டது உள்ளடக்கம் சேர்க்கப்பட்டது
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வரிசை 1:
{{Infobox Galaxy
| name = Pinwheel Galaxy
| image = M101 hires STScI-PRC2006-10a.jpg
| image_size = 300px
| epoch = [[Epoch (astronomy)#Julian years and J2000|J2000]]
| constellation name = [[Ursa Major]]
| ra = {{RA|14|03|12.6}}
| dec = {{DEC|+54|20|57}}
| type = SAB(rs)cd
| z = 0.000804
| h_radial_v = {{nowrap|241 ± 2 [[Metre per second|km/s]]}}
| dist_ly = 20.9 ± 1.8 M[[light-year|ly]] (6.4 ± 0.5 M[[parsec|pc]])
| appmag_v = 7.86
| size_v = 28′.8 × 26′.9
| size = ~170,000 ly in diameter<ref>{{cite web|title=The Pinwheel Galaxy|url=https://www.nasa.gov/multimedia/imagegallery/image_feature_2265.html|date=31 May 2012|editor=NASA Content Administrator|publisher=NASA|accessdate=4 March 2017}}</ref>
| stars = 1 trillion (10<sup>12</sup>)
| notes =
| names = [[Messier object|Messier]] 101, M101, [[New General Catalogue|NGC]] 5457, [[Uppsala General Catalogue|UGC]] 8981, [[Principal Galaxies Catalogue|PGC]] 50063, [[Atlas of Peculiar Galaxies|Arp]] 26
| references = <ref name="ned">
{{cite web
| work=NASA/IPAC Extragalactic Database
| title=NED results for object MESSIER 101
| url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Messier+101&img_stamp=yes&extend=no
| accessdate=2006-12-06
}}</ref><ref name="shappee">
{{cite journal
|last=Shappee
|first=Benjamin
|author2=Stanek, Kris
|title=A New Cepheid Distance to the Giant Spiral M101 Based on Image Subtraction of Hubble Space Telescope/Advanced Camera for Surveys Observations
|journal=Astrophysical Journal
|date=June 2011
|volume=733
|issue=2
|pages=124
|doi=10.1088/0004-637X/733/2/124
|bibcode = 2011ApJ...733..124S |arxiv = 1012.3747 }}</ref><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=0-933346-51-4
}}</ref><ref name=ned-dist>
{{cite web
| title=Distance Results for Messier 101
| work=NASA/IPAC Extragalactic Database
|url=http://nedwww.ipac.caltech.edu/cgi-bin/nDistance?name=MESSIER+101
| accessdate=2010-05-01
}}</ref><ref name="SIMBAD-M101">
{{cite simbad
|title=M 101
| accessdate=2009-11-29
}}</ref><ref name=GAXEL>
{{cite journal
|last=Armando |first=Gil de Paz
|display-authors=4
|author2=Boissier |author3=Madore |author4=Seibert |author5=Boselli |author6= et al.
| title=The GALEX Ultraviolet Atlas of Nearby Galaxies
| journal=[[Astrophysical Journal Supplement]]
| volume=173
|issue=2 |pages=185–255 | date=2007
| arxiv=astro-ph/0606440
| doi=10.1086/516636
| bibcode=2007ApJS..173..185G
}}</ref>
}}
The '''Pinwheel Galaxy''' (also known as '''Messier 101''', '''M101''' or '''NGC 5457''') is a face-on [[spiral galaxy]] distanced 21 million [[light-year]]s (six [[megaparsec]]s)<ref name="shappee"/> away from earth in the [[constellation]] [[Ursa Major]]. First discovered by [[Pierre Méchain]] on March 27, 1781, it was communicated to [[Charles Messier]] who verified its position for inclusion in the ''Messier Catalogue'' as one of its final entries.
On February 28, 2006, [[NASA]] and the [[European Space Agency]] released a very detailed image of the Pinwheel Galaxy, which was the largest and most detailed image of a galaxy by [[Hubble Space Telescope]] at the time.<ref>{{cite web|url=https://www.nasa.gov/mission_pages/hubble/science/hst_spiral_m10_prt.htm|title=Hubble's Largest Galaxy Portrait Offers a New High-Definition View|date=28 February 2006|publisher=NASA|accessdate=4 February 2018}}</ref> The image was composed of 51 individual exposures, plus some extra ground-based photos.
On August 24, 2011, a [[Type Ia supernova]], [[SN 2011fe]], was discovered in M101.
== Discovery ==
Pierre Méchain, the discoverer of Messier 101, described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the great Bear. It is difficult to distinguish when one lits the [grating] wires."<ref name="SEDS Historical Notes">{{cite web|url=http://messier.seds.org/Mdes/dm101.html|title=Messier 101|author=Hartmut Frommert|work=SEDS Messier Database|accessdate=4 March 2018}}</ref>
[[William Herschel]] noted in 1784 that "...in my 7, 10, and 20-feet [focal length] reflectors shewed a mottled kind of nebulosity, which I shall call resolvable; so that I expect my present telescope will, perhaps, render the stars visible of which I suppose them to be composed."<ref name="SEDS Historical Notes"/>
[[William Parsons, 3rd Earl of Rosse|Lord Rosse]] observed M101 in his 72-inch diameter [[Newtonian telescope|Newtonian reflector]] during the second half of the 19th century. He was the first to make extensive note of the spiral structure and made several sketches.<ref name="SEDS Historical Notes"/>
To observe the spiral structure in modern instruments requires a fairly large instrument, very dark skies, and a low power eyepiece.<ref>{{cite web|title=M 101|url=https://messierobjects101.com/messier-object-m101-m102-pinwheel-galaxy/|work=Messier Objects Mobile — Charts, Maps & Photos|accessdate=4 March 2018}}</ref>
== Structure and composition ==
[[File:NASA-SpiralGalaxyM101-20140505.jpg|thumb|left|250px|M101 - combined infrared, visible, and x-ray images.]]
M101 is a large galaxy, with a diameter of 170,000 light-years. By comparison, the [[Milky Way]] has a diameter of 100,000 light years. It has around a trillion stars, ten times the amount in the Milky Way.<ref>{{Cite news|url=http://www.slate.com/blogs/bad_astronomy/2006/02/28/hubble_delivers_again_m101.html|title=Hubble delivers again: M101|last=Plait|first=Phil|date=2006-02-28|work=Slate|access-date=2018-05-04|language=en-US|issn=1091-2339}}</ref> It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses.<ref name="M101 mass">{{cite journal |author=Comte, G. |author2=Monnet, G. |author3=Rosado, M. |last-author-amp=yes|date=1979 |title=An optical study of the galaxy M 101 - Derivation of a mass model from the kinematic of the gas |journal=Astronomy and Astrophysics |volume=72 |pages=73–81 |bibcode=1979A&A....72...73C }}</ref>
M101 is noted for its high population of [[H II region]]s, many of which are very large and bright. H II regions usually accompany the enormous clouds of high density molecular hydrogen gas contracting under their own gravitational force where [[Star formation|stars form]]. H II regions are ionized by large numbers of extremely bright and hot young stars; those in M101 are capable of creating hot [[superbubble]]s.<ref>{{cite journal |url=http://iopscience.iop.org/0004-637X/554/1/202/ |title=ROSAT X-Ray Observations of the Spiral Galaxy M81 |journal=The Astrophysical Journal |volume=554 |issue=1 |author=Immler, Stefan |author2=Wang, Q. Daniel |last-author-amp=yes|date=2001 |page=202 |doi=10.1086/321335 |accessdate=12 May 2014|arxiv = astro-ph/0102021 |bibcode = 2001ApJ...554..202I }}</ref> In a 1990 study, 1264 H II regions were cataloged in the galaxy.<ref>{{cite journal |bibcode=1990ApJS...73..661H |title=The H II regions of M101. I - an atlas of 1264 emission regions |author=Hodge, Paul W. |date=August 1990 |journal=Astrophysical Journal Supplement Series |volume=73 |pages=661–670 |doi=10.1086/191483 |last2=Gurwell |first2=Mark |last3=Goldader |first3=Jeffrey D. |last4=Kennicutt |first4=Robert C., Jr. }}</ref> Three are prominent enough to receive [[New General Catalogue]] numbers - NGC 5461, NGC 5462, and NGC 5471.<ref>{{Cite journal|arxiv=astro-ph/9903334|last1= Giannakopoulou-Creighton|first1= J.|title= Star formation in the giant HII regions of M101|journal= The Astrophysical Journal|volume= 522|pages= 238|last2= Fich|first2= M.|last3= Wilson|first3= C. D.|date= 1999|doi= 10.1086/307619|bibcode = 1999ApJ...522..238G }}</ref>
M101 is asymmetrical due to the tidal forces from interactions with its companion galaxies. These gravitational interactions compress [[Interstellar medium|interstellar hydrogen gas]], which then triggers strong [[star formation]] activity in M101's spiral arms that can be detected in ultraviolet images.<ref>{{cite journal |url=http://iopscience.iop.org/0004-637X/481/1/169 |title=Ultraviolet Signatures of Tidal Interaction in the Giant Spiral Galaxy M101 |author=Waller, William H. |journal=The Astrophysical Journal |volume=481 |issue=1 |page=169 |date=20 May 1997 |doi=10.1086/304057 |accessdate=12 May 2014|last2=Bohlin |display-authors=4 |first2=Ralph C. |last3=Cornett |first3=Robert H. |last4=Fanelli |first4=Michael N. |last5=Freedman |first5=Wendy L. |last6=Hill |first6=Jesse K. |last7=Madore |first7=Barry F. |last8=Neff |first8=Susan G. |last9=Offenberg |first9=Joel D. |last10=O'Connell |first10=Robert W. |last11=Roberts |first11=Morton S. |last12=Smith |first12=Andrew M. |last13=Stecher |first13=Theodore P. |arxiv = astro-ph/9612165 |bibcode = 1997ApJ...481..169W }}</ref>
In 2001, the x-ray source P98, located in M101, was identified as an [[ultra-luminous X-ray source]] - a source more powerful than any single star but less powerful than a whole galaxy - using the [[Chandra X-ray Observatory]]. It received the designation M101 ULX-1. In 2005, [[Hubble Space Telescope|Hubble]] and [[XMM-Newton]] observations showed the presence of an optical counterpart, strongly indicating that M101 ULX-1 is an [[x-ray binary]].<ref>{{cite journal |url=http://iopscience.iop.org/1538-4357/620/1/L31/fulltext/19014.text.html |title=The Optical Counterpart of M101 ULX-1 |journal=The Astrophysical Journal |volume=620 |issue=1 |pages=L31–L34 |author=Kuntz, K.D. |display-authors=etal |doi=10.1086/428571|bibcode=2005ApJ...620L..31K |date=10 February 2005 |accessdate=12 May 2014}}</ref> Further observations showed that the system deviated from expected models - the black hole is just 20 to 30 [[solar mass]]es, and consumes material (including captured stellar wind) at a higher rate than theory suggests.<ref>{{Cite journal|arxiv=1312.0337|last1=Liu|first1=Jifeng|title=Puzzling accretion onto a black hole in the ultraluminous X-ray source M101 ULX-1|journal=Nature|volume=503|issue=7477|pages=500|last2= Bregman|display-authors=4|first2=Joel N.|last3=Bai|first3=Yu|last4=Justham|first4=Stephen|last5=Crowther|first5=Paul|date=2013|doi=10.1038/nature12762|bibcode = 2013Natur.503..500L }}</ref>
== Companion galaxies ==
M101 has five prominent companion galaxies: [[NGC 5204]], [[NGC 5474]], [[NGC 5477]], [[NGC 5585]], and [[Holmberg IV]].<ref name="carnegieatlas" >{{cite book | author=A. Sandage | author2=J. Bedke | date=1994| title=Carnegie Atlas of Galaxies| publisher=[[Carnegie Institution of Washington]]| isbn=0-87279-667-1}}</ref> As stated above, the gravitational interaction between M101 and its satellites may have triggered the formation of the grand design pattern in M101. M101 has also probably distorted the companion galaxy NGC 5474.<ref name="carnegieatlas"/> M101 and its companion galaxies comprise most or possibly all of the [[M101 Group]].<ref name="nbg">{{cite book
| author=R. B. Tully
| date=
| title=Nearby Galaxies Catalog
| publisher=[[Cambridge University Press]]
| isbn=0-521-35299-1
}}</ref><ref name="fouqueetal1992">
{{cite journal
| author=P. Fouque
| author2=E. Gourgoulhon
| author3=P. Chamaraux
| author4=G. Paturel
| edition=2nd
| title=Groups of galaxies within 80 Mpc. II – The catalogue of groups and group members
| journal=[[Astronomy and Astrophysics Supplement]]
| volume=93 | pages=211–233
| bibcode=1992A&AS...93..211F
| date=1992
}}</ref><ref name="garcia1993">
{{cite journal
| author=A. Garcia
| date=1993
| title=General study of group membership. II – Determination of nearby groups
| journal=[[Astronomy and Astrophysics Supplement]]
| volume=100 | pages=47–90
|bibcode=1993A&AS..100...47G
}}</ref><ref name="giuricinetal2002">
{{cite journal
| last=Giuricin | first=G.
| last2=Marinoni | first2=C.
| last3=Ceriani | first3=L.
| last4=Pisani | first4=A.
| date=2000
| title=Nearby Optical Galaxies: Selection of the Sample and Identification of Groups
| journal=[[Astrophysical Journal]]
| volume=543
| issue=1 | pages=178–194
| bibcode=2000ApJ...543..178G
| doi=10.1086/317070
|arxiv = astro-ph/0001140
}}</ref>
==Supernovae==
On August 24, 2011, a [[Type Ia supernova]], [[SN 2011fe]], initially designated PTF 11kly, was discovered in M101. The supernova was [[Apparent magnitude|visual magnitude]] 17.2 at discovery and reached magnitude 9.9 at its peak.<ref>{{cite web |title=Young Type Ia Supernova PTF11kly in M101 |url=http://www.astronomerstelegram.org/?read=3581 |author=Nugent, Peter |display-authors=etal |publisher=The Astronomer's Telegram |date=24 August 2011 |accessdate=25 August 2011}}</ref><ref>{{cite web |title=Supernova Caught in the Act |url=http://www.nersc.gov/news-publications/science-news/2011/supernova-caught-in-the-act/ |author=Nugent, Peter |display-authors=etal |accessdate=7 September 2011}}</ref><ref>{{cite web |title=Supernova 2011fe in M101|author=Hartmut Frommert|author2=Christine Kronberg |last-author-amp=yes|url=http://messier.seds.org/more/m101_sn2011fe.html |date=15 Sep 2011 |accessdate=17 Sep 2011}}</ref> This was the fourth supernova recorded in M101. The first, SN 1909A, was discovered by [[Max Wolf]] in January 1909 and reached magnitude 12.1. SN 1951H reached magnitude 17.5 in September 1951 and SN 1970G reached magnitude 11.5 in January 1970.<ref>Stoyan, Ronald Atlas of the Messier Objects, Cambridge University Press 2008 page 329</ref>
On February 10, 2015, a [[luminous red nova]], known as [[M101 OT2015-1]] was discovered in the Pinwheel Galaxy by [[Dumitru Ciprian Vîntdevară]] from [[Planetarium and Astronomical Observatory of the Museum Vasile Parvan]] in [[Bârlad]], [[Romania]].<ref>{{cite web |title=Transient object followup reports |url=http://www.cbat.eps.harvard.edu/unconf/followups/J14021678+5426205.html|publisher=Central Bureau for Astronomical Telegrams}}</ref>
== Gallery ==
<gallery>
File:M101 S1 SC CB Shadows Rotate HVLG SS HPF1.tif|M101 - taken using an 8" SCT (San Diego, CA).
File:Supernova in M101 2011-08-25.jpg|M101 - noting Type Ia supernova [[SN 2011fe]].
File:The Pinwheel Galaxy - M101.jpg|M101 - captured using amateur equipment.
</gallery>
== See also ==
* [[Messier 74]] – a similar face-on spiral galaxy
* [[Messier 83]] – a similar face-on spiral galaxy that is sometimes called the Southern Pinwheel Galaxy
* [[Messier 99]] – a similar face-on spiral galaxy
* [[Triangulum Galaxy]] – another galaxy sometimes called the Pinwheel Galaxy
== References ==
{{reflist|30em}}
== External links ==
{{commons|Messier 101|Pinwheel Galaxy}}
* {{WikiSky|name=The Pinwheel Galaxy}}
* {{cite web|last=Harutyunyan|first=Avet|title=M101 – Pinwheel Galaxy|url=http://www.deepskyvideos.com/videos/messier/M101_pinwheel.html|work=Deep Space Videos|publisher=[[Brady Haran]]|author2=Merrifield, Mike |author3=Dhillon, Vik }}
* {{cite APOD|date=14 April 2009|title=M101: The Pinwheel Galaxy|accessdate=4 March 2018}}
* {{cite web|url=http://www.constellation-guide.com/pinwheel-galaxy-messier-101/|title=Pinwheel Galaxy – Messier 101|work=Constellation Guide|date=31 May 2013}}
* {{cite web|url=http://www.takayuki-astro.com/st2k_m101_mt200.html|title=Spiral Galaxy, M101|work=Astrophotography by Takayuki Yoshida|author=Yoshida, Takayuki}}
{{Sky|14|03|12.6|+|54|20|57|27000000}}
{{Messier objects}}
{{Ngc55}}
[[Category:Flocculent spiral galaxies]]
[[Category:Intermediate spiral galaxies]]
[[Category:M101 Group]]
[[Category:Ursa Major (constellation)]]
[[Category:Messier objects]]
[[Category:NGC objects]]
[[Category:UGC objects|08981]]
[[Category:Principal Galaxies Catalogue objects|50063]]
[[Category:Arp objects|026]]
[[Category:Astronomical objects discovered in 1781]]
[[Category:Discoveries by Pierre Méchain]]
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