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Messier 81

January 01, 1970

For other uses, see M81 (disambiguation).

Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major. It has a D25 isophotal diameter of 29.44 kiloparsecs (96,000 light-years).[2][5] Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus (which harbors a 70 million M☉[6] supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers.[7] In late February 2022, astronomers reported that M81 may be the source of FRB 20200120E, a repeating fast radio burst.[8][9]

Messier 81
The HST's view of M81, with its open star clusters, globular star clusters, and regions of fluorescent gas.
Observation data (J2000 epoch)
ConstellationUrsa Major[1]
Right ascension09h 55m 33.2s[2]
Declination+69° 3′ 55″[2]
Redshift−0.000113
Heliocentric radial velocity−34
Galactocentric velocity73
Apparent magnitude (V)6.94[3][4]
Characteristics
TypeSA(s)ab,[2] LINER[2]
Size29.44 kiloparsecs (96,000 light-years)
(diameter; 25.0 mag/arcsec2 B-band isophote)[2][5]
Apparent size (V)26.9 × 14.1 moa[2]
Other designations
NGC 3031, UGC 5318, MCG+12-10-010, PGC 28630, Bode's Galaxy[3]

Discovery edit

Messier 81 was first discovered by Johann Elert Bode on 31 December 1774.[10] Thus, it is sometimes referred to as "Bode's Galaxy". In 1779, Pierre Méchain and Charles Messier reidentified Bode's object, hence listed it in the Messier Catalogue.[10]

Visibility edit

The galaxy is to be found approximately 10° northwest of Alpha Ursae Majoris (Dubhe) along with several other galaxies in the Messier 81 Group.[7][11] Its apparent magnitude due to its distance means it requires a good night sky and only rises very briefly and extremely low at its southernmost limit from Earth's surface, about the 20th parallel south.

Messier 81 and Messier 82 are considered ideal for viewing using binoculars and small telescopes.[7][11] The two objects are generally not observable to the unaided eye, although highly experienced amateur astronomers may be able to see Messier 81 under exceptional observing conditions with a very dark sky.[7][12] Telescopes with apertures of 8 inches (20 cm) or larger are needed to distinguish structures in the galaxy.[11]

 
An infrared image of Messier 81 taken by the Spitzer Space Telescope. The blue colors represent stellar emission observed at 3.6 μm.[13] The green colors represent 8 μm emission originating primarily from polycyclic aromatic hydrocarbons in the interstellar medium.[13] The red colors represent 24 μm emission originating from heated dust in the interstellar medium.[14]

The galaxy is best observed during April. [15]

Interstellar dust edit

Most of the emission at infrared wavelengths originates from interstellar dust.[14][16] This interstellar dust is found primarily within the galaxy's spiral arms, and it has been shown to be associated with star formation regions.[14][16] The general explanation is that the hot, short-lived blue stars that are found within star formation regions are very effective at heating the dust and thus enhancing the infrared dust emission from these regions.

Globular clusters edit

It is estimated M81 has 210 ± 30 globular clusters.[17] In late February 2022, astronomers reported that M81 may be the source of FRB 20200120E, a repeating fast radio burst.[8][9]

Supernovae edit

 
M81 (left) and M82 (right). M82 is one of two galaxies strongly influenced gravitationally by M81. The other, NGC 3077, is located off the top edge of this image.
 
M81 with satellite galaxy Holmberg IX in the top center-right corner

Only one supernova has been detected in Messier 81.[18] The supernova, named SN 1993J, was discovered on 28 March 1993 by F. García in Spain.[19] At the time, it was the second brightest supernova observed in the 20th century,[20] peaking at an apparent magnitude of 10.7. The spectral characteristics of the supernova changed over time. Initially, it looked more like a type II supernova (a supernova formed by the explosion of a supergiant star) with strong hydrogen spectral line emission, but later the hydrogen lines faded and strong helium spectral lines appeared, making the supernova look more like a type Ib.[20][21]

Moreover, the variations in SN 1993J's luminosity over time were not like the variations observed in other type II supernovae,[22][23] but did resemble the variations observed in type Ib supernovae.[24] Hence, the supernova has been classified as a type IIb, a transitory class between type II and type Ib.[21] The scientific results from this supernova suggested that type Ib and Ic supernovae were formed through the explosions of giant stars through processes similar to those taking place in type II supernovae.[21][25] Despite the uncertainties in modeling the unusual supernova, it was also used to estimate a very approximate distance of 8.5 ± 1.3 Mly (2.6 ± 0.4 Mpc) to Messier 81.[20] As a local galaxy, the Central Bureau for Astronomical Telegrams (CBAT) tracks novae in M81 along with M31 and M33.[26]

Environment edit

Messier 81 is the largest galaxy in the M81 Group, a group of 34 in the constellation Ursa Major.[27] At approximately 11.7 Mly (3.6 Mpc) from the Earth, it makes this group and the Local Group, containing the Milky Way,[27] relative neighbors in the Virgo Supercluster.

Gravitational interactions of M81 with M82 and NGC 3077[28] have stripped hydrogen gas away from all three galaxies, forming gaseous filamentary structures in the group.[28] Moreover, these interactions have allowed interstellar gas to fall into the centers of M82 and NGC 3077, leading to vigorous star formation or starburst activity there.[28]

Distance edit

The distance to Messier 81 has been measured by Freedman et al[29] to be 3.63 ± 0.34 Megaparsecs (11.8 ± 1.1 million light years) by using the Hubble Space Telescope to identify classical Cepheid variables and measure their periods using the period-luminosity relation discovered by Henrietta Swan Leavitt.

See also edit

References edit

  1. ^ Dreyer, J. L. E. (1988). Sinnott, R. W. (ed.). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters. Sky Publishing Corporation / Cambridge University Press. ISBN 978-0-933346-51-2.
  2. ^ a b c d e f g h i j "NASA/IPAC Extragalactic Database". Results for Messier 081. Retrieved 6 November 2022.
  3. ^ a b "M 81". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 November 2009.
  4. ^ Armando, Gil de Paz; Boissier, Samuel; Madore, Barry F.; Seibert, Mark; Joe, Young H.; Boselli, Alessandro; Wyder, Ted K.; Thilker, David; Bianchi, Luciana; Rey, Soo-Chang; Rich, R. Michael; Barlow, Tom A.; Conrow, Tim; Forster, Karl; Friedman, Peter G.; Martin, D. Christopher; Morrissey, Patrick; Neff, Susan G.; Schiminovich, David; Small, Todd; Donas, José; Heckman, Timothy M.; Lee, Young-Wook; Milliard, Bruno; Szalay, Alex S.; Yi, Sukyoung (2007). "The GALEX Ultraviolet Atlas of Nearby Galaxies". Astrophysical Journal. 173 (2): 185–255. arXiv:astro-ph/0606440. Bibcode:2007ApJS..173..185G. doi:10.1086/516636. S2CID 119085482.
  5. ^ a b De Vaucouleurs, Gerard; De Vaucouleurs, Antoinette; Corwin, Herold G.; Buta, Ronald J.; Paturel, Georges; Fouque, Pascal (1991). Third Reference Catalogue of Bright Galaxies. Bibcode:1991rc3..book.....D.
  6. ^ Devereux, N.; Ford, H.; Tsvetanov, Z.; Jocoby, J. (2003). "STIS Spectroscopy of the Central 10 Parsecs of M81: Evidence for a Massive Black Hole". Astronomical Journal. 125 (3): 1226–1235. Bibcode:2003AJ....125.1226D. doi:10.1086/367595. S2CID 121093306.
  7. ^ a b c d O'Meara, S. J. (1998). The Messier Objects. Cambridge University Press. ISBN 978-0-521-55332-2.
  8. ^ a b Starr, Michelle (23 February 2022). "Mysterious Repeating Fast Radio Burst Traced to Very Unexpected Location". ScienceAlert. Retrieved 24 February 2022.
  9. ^ a b Kirsten, F; et al. (23 February 2022). "A repeating fast radio burst source in a globular cluster". Nature. 602 (7898): 585–589. arXiv:2105.11445. Bibcode:2022Natur.602..585K. doi:10.1038/s41586-021-04354-w. PMID 35197615. S2CID 235166402. Retrieved 24 February 2022.
  10. ^ a b Jones, K. G. (1991). Messier's Nebulae and Star Clusters (2nd ed.). Cambridge University Press. ISBN 978-0-521-37079-0.
  11. ^ a b c Eicher, D. J. (1988). The Universe from Your Backyard. Cambridge University Press. ISBN 978-0-521-36299-3.
  12. ^ Stephen Uitti. "Farthest Naked Eye Object". from the original on 19 August 2008. Retrieved 1 November 2008.
  13. ^ a b Willner, S. P.; Ashby, M. L. N.; Barmby, P.; Fazio, G. G.; Pahre, M.; Smith, H. A.; Kennicutt Jr., R. C.; Calzetti, D.; Dale, D. A.; Draine, B. T.; Regan, M. W.; Malhotra, S.; Thornley, M. D.; Appleton, P. N.; Frayer, D.; Helou, G.; Stolovy, S.; Storrie-Lombardi, L. (2004). "Infrared Array Camera (IRAC) Observations of M81". Astrophysical Journal Supplement Series. 154 (1): 222–228. arXiv:astro-ph/0405626. Bibcode:2004ApJS..154..222W. doi:10.1086/422913. S2CID 16609000.
  14. ^ a b c Gordon, K. D.; Pérez-González, P. G.; Misselt, K. A.; Murphy, E. J.; Bendo, G. J.; Walter, F.; Thornley, M. D.; Kennicutt Jr., R. C.; Rieke, G. H.; Engelbracht, C. W.; Smith, J.-D. T.; Alonso-Herrero, A.; Appleton, P. N.; Calzetti, D.; Dale, D. A.; Draine, B. T.; Frayer, D. T.; Helou, G.; Hinz, J. L.; Hines, D. C.; Kelly, D. M.; Morrison, J. E.; Muzerolle, J.; Regan, M. W.; Stansberry, J. A.; Stolovy, S. R.; Storrie-Lombardi, L. J.; Su, K. Y. L.; Young, E. T. (2004). "Spatially Resolved Ultraviolet, Hα, Infrared, and Radio Star Formation in M81". Astrophysical Journal Supplement Series. 154 (1): 215–221. arXiv:astro-ph/0406064. Bibcode:2004ApJS..154..215G. doi:10.1086/422714. S2CID 17283721.
  15. ^ https://science.nasa.gov/mission/hubble/science/explore-the-night-sky/hubble-messier-catalog/messier-81/
  16. ^ a b Pérez-González, P. G.; Kennicutt Jr., R. C.; Gordon, K. D.; Misselt, K. A.; Gil De Paz, A.; Engelbracht, C. W.; Rieke, G. H.; Bendo, G. J.; Bianchi, L.; Boissier, S.; Calzetti, D.; Dale, D. A.; Draine, B. T.; Jarrett, T. H.; Hollenbach, D.; Prescott, M. K. M. (2006). "Ultraviolet through Far-Infrared Spatially Resolved Analysis of the Recent Star Formation in M81 (NGC 3031)". Astrophysical Journal. 648 (2): 987–1006. arXiv:astro-ph/0605605. Bibcode:2006ApJ...648..987P. doi:10.1086/506196. S2CID 13901458.
  17. ^ Chandar, Rupali; Whitmore, Bradley; Lee, Myung Gyoon (10 August 2004). "The Globular Cluster Systems of Five Nearby Spiral Galaxies: New Insights from Hubble Space TelescopeImaging". The Astrophysical Journal. 611 (1): 220–244. arXiv:astro-ph/0407460. Bibcode:2004ApJ...611..220C. doi:10.1086/421934. ISSN 0004-637X.
  18. ^ "NASA/IPAC Extragalactic Database". Results for extended name search on NGC 3031. Retrieved 27 February 2007.
  19. ^ Ripero, J.; Garcia, F.; Rodriguez, D.; Pujol, P.; Filippenko, A. V.; Treffers, R. R.; Paik, Y.; Davis, M.; Schlegel, D.; Hartwick, F. D. A.; Balam, D. D.; Zurek, D.; Robb, R. M.; Garnavich, P.; Hong, B. A. (1993). "Supernova 1993J in NGC 3031". IAU Circular. 5731: 1. Bibcode:1993IAUC.5731....1R.
  20. ^ a b c Schmidt, B.P.; Kirshner, R.P.; Eastman, R.G.; Grashuis, R.; Dell'Antonio, I.; Caldwell, N.; Foltz, C.; Huchra, John P.; Milone, Alejandra A. E. (1993). "The unusual supernova SN1993J in the galaxy M81". Nature. 364 (6438): 600–602. Bibcode:1993Natur.364..600S. doi:10.1038/364600a0. S2CID 4304547.
  21. ^ a b c Filippenko, A. V.; Matheson, T.; Ho, L. C. (1993). "The "Type IIb" Supernova 1993J in M81: A Close Relative of Type Ib Supernovae". Astrophysical Journal Letters. 415: L103–L106. Bibcode:1993ApJ...415L.103F. doi:10.1086/187043.
  22. ^ Benson, P. J.; Herbst, W.; Salzer, J. J.; Vinton, G.; Hanson, G. J.; Ratcliff, S. J.; Winkler, P. F.; Elmegreen, D. M.; Chromey, F.; Strom, C.; Balonek, T. J.; Elmegreen, B. G. (1994). "Light curves of SN 1993J from the Keck Northeast Astronomy Consortium". Astronomical Journal. 107: 1453–1460. Bibcode:1994AJ....107.1453B. doi:10.1086/116958.
  23. ^ Wheeler, J. C.; Barker, E.; Benjamin, R.; Boisseau, J.; Clocchiatti, A.; De Vaucouleurs, G.; Gaffney, N.; Harkness, R. P.; Khokhlov, A. M.; Lester, D. F.; Smith, B. J.; Smith, V. V.; Tomkin, J. (1993). "Early Observations of SN 1993J in M81 at McDonald Observatory". Astrophysical Journal. 417: L71–L74. Bibcode:1993ApJ...417L..71W. doi:10.1086/187097.
  24. ^ Richmond, M. W.; Treffers, R. R.; Filippenko, A. V.; Palik, Y.; Leibundgut, B.; Schulman, E.; Cox, C. V. (1994). "UBVRI photometry of SN 1993J in M81: The first 120 days". Astronomical Journal. 107: 1022–1040. Bibcode:1994AJ....107.1022R. doi:10.1086/116915.
  25. ^ Filippenko, A. V.; Matheson, T.; Barth, A. J. (1994). "The peculiar type II supernova 1993J in M81: Transition to the nebular phase". Astronomical Journal. 108: 2220–2225. Bibcode:1994AJ....108.2220F. doi:10.1086/117234.
  26. ^ Bishop, David. . supernovae.net (International Supernovae Network). Archived from the original on 8 April 2010. Retrieved 11 September 2010.
  27. ^ a b Karachentsev, I. D. (2005). "The Local Group and Other Neighboring Galaxy Groups". Astronomical Journal. 129 (1): 178–188. arXiv:astro-ph/0410065. Bibcode:2005AJ....129..178K. doi:10.1086/426368. S2CID 119385141.
  28. ^ a b c Yun, M. S.; Ho, P. T. P.; Lo, K. Y. (1994). "A high-resolution image of atomic hydrogen in the M81 group of galaxies". Nature. 372 (6506): 530–532. Bibcode:1994Natur.372..530Y. doi:10.1038/372530a0. PMID 7990925. S2CID 4369085.
  29. ^ Freedman, Wendy (1994). "The Hubble Space Telescope Extragalactic Distance Scale Project. I. The Discovery of Cepheids and a New Distance to M81". The Astrophysical Journal. 427 (June): 628–655. Bibcode:1994ApJ...427..628F. doi:10.1086/174172 – via Astrophysics Data System.

External links edit

 
Wikimedia Commons has media related to Messier 81.
  • M81, SEDS Messier pages
  • NASA Astronomy Picture of the Day: Bright Galaxy M81 (20 June 2002)
  • NightSkyInfo.com – M81, Bode's Galaxy
  • Messier 81 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
  • ESA/Hubble images of M81
  • Galaxy Messier 81 (Bode's Galaxy)
  • Deep image of the M81 Area
  • Bode's Galaxy at Constellation Guide


January 01, 1970
messier, other, uses, disambiguation, also, known, 3031, bode, galaxy, grand, design, spiral, galaxy, about, million, light, years, away, constellation, ursa, major, isophotal, diameter, kiloparsecs, light, years, because, relative, proximity, milky, galaxy, l. For other uses see M81 disambiguation Messier 81 also known as NGC 3031 or Bode s Galaxy is a grand design spiral galaxy about 12 million light years away in the constellation Ursa Major It has a D25 isophotal diameter of 29 44 kiloparsecs 96 000 light years 2 5 Because of its relative proximity to the Milky Way galaxy large size and active galactic nucleus which harbors a 70 million M 6 supermassive black hole Messier 81 has been studied extensively by professional astronomers The galaxy s large size and relatively high brightness also makes it a popular target for amateur astronomers 7 In late February 2022 astronomers reported that M81 may be the source of FRB 20200120E a repeating fast radio burst 8 9 Messier 81The HST s view of M81 with its open star clusters globular star clusters and regions of fluorescent gas Observation data J2000 epoch ConstellationUrsa Major 1 Right ascension09h 55m 33 2s 2 Declination 69 3 55 2 Redshift 0 000113Heliocentric radial velocity 34Galactocentric velocity73Apparent magnitude V 6 94 3 4 CharacteristicsTypeSA s ab 2 LINER 2 Size29 44 kiloparsecs 96 000 light years diameter 25 0 mag arcsec2 B band isophote 2 5 Apparent size V 26 9 14 1 moa 2 Other designationsNGC 3031 UGC 5318 MCG 12 10 010 PGC 28630 Bode s Galaxy 3 Contents 1 Discovery 2 Visibility 3 Interstellar dust 4 Globular clusters 5 Supernovae 6 Environment 7 Distance 8 See also 9 References 10 External linksDiscovery editMessier 81 was first discovered by Johann Elert Bode on 31 December 1774 10 Thus it is sometimes referred to as Bode s Galaxy In 1779 Pierre Mechain and Charles Messier reidentified Bode s object hence listed it in the Messier Catalogue 10 Visibility editThe galaxy is to be found approximately 10 northwest of Alpha Ursae Majoris Dubhe along with several other galaxies in the Messier 81 Group 7 11 Its apparent magnitude due to its distance means it requires a good night sky and only rises very briefly and extremely low at its southernmost limit from Earth s surface about the 20th parallel south Messier 81 and Messier 82 are considered ideal for viewing using binoculars and small telescopes 7 11 The two objects are generally not observable to the unaided eye although highly experienced amateur astronomers may be able to see Messier 81 under exceptional observing conditions with a very dark sky 7 12 Telescopes with apertures of 8 inches 20 cm or larger are needed to distinguish structures in the galaxy 11 nbsp An infrared image of Messier 81 taken by the Spitzer Space Telescope The blue colors represent stellar emission observed at 3 6 mm 13 The green colors represent 8 mm emission originating primarily from polycyclic aromatic hydrocarbons in the interstellar medium 13 The red colors represent 24 mm emission originating from heated dust in the interstellar medium 14 The galaxy is best observed during April 15 Interstellar dust editMost of the emission at infrared wavelengths originates from interstellar dust 14 16 This interstellar dust is found primarily within the galaxy s spiral arms and it has been shown to be associated with star formation regions 14 16 The general explanation is that the hot short lived blue stars that are found within star formation regions are very effective at heating the dust and thus enhancing the infrared dust emission from these regions Globular clusters editIt is estimated M81 has 210 30 globular clusters 17 In late February 2022 astronomers reported that M81 may be the source of FRB 20200120E a repeating fast radio burst 8 9 Supernovae edit nbsp M81 left and M82 right M82 is one of two galaxies strongly influenced gravitationally by M81 The other NGC 3077 is located off the top edge of this image nbsp M81 with satellite galaxy Holmberg IX in the top center right corner Only one supernova has been detected in Messier 81 18 The supernova named SN 1993J was discovered on 28 March 1993 by F Garcia in Spain 19 At the time it was the second brightest supernova observed in the 20th century 20 peaking at an apparent magnitude of 10 7 The spectral characteristics of the supernova changed over time Initially it looked more like a type II supernova a supernova formed by the explosion of a supergiant star with strong hydrogen spectral line emission but later the hydrogen lines faded and strong helium spectral lines appeared making the supernova look more like a type Ib 20 21 Moreover the variations in SN 1993J s luminosity over time were not like the variations observed in other type II supernovae 22 23 but did resemble the variations observed in type Ib supernovae 24 Hence the supernova has been classified as a type IIb a transitory class between type II and type Ib 21 The scientific results from this supernova suggested that type Ib and Ic supernovae were formed through the explosions of giant stars through processes similar to those taking place in type II supernovae 21 25 Despite the uncertainties in modeling the unusual supernova it was also used to estimate a very approximate distance of 8 5 1 3 Mly 2 6 0 4 Mpc to Messier 81 20 As a local galaxy the Central Bureau for Astronomical Telegrams CBAT tracks novae in M81 along with M31 and M33 26 Environment editMessier 81 is the largest galaxy in the M81 Group a group of 34 in the constellation Ursa Major 27 At approximately 11 7 Mly 3 6 Mpc from the Earth it makes this group and the Local Group containing the Milky Way 27 relative neighbors in the Virgo Supercluster Gravitational interactions of M81 with M82 and NGC 3077 28 have stripped hydrogen gas away from all three galaxies forming gaseous filamentary structures in the group 28 Moreover these interactions have allowed interstellar gas to fall into the centers of M82 and NGC 3077 leading to vigorous star formation or starburst activity there 28 Distance editThe distance to Messier 81 has been measured by Freedman et al 29 to be 3 63 0 34 Megaparsecs 11 8 1 1 million light years by using the Hubble Space Telescope to identify classical Cepheid variables and measure their periods using the period luminosity relation discovered by Henrietta Swan Leavitt See also editList of galaxies List of Messier objects Messier object New General CatalogueReferences edit Dreyer J L E 1988 Sinnott R W ed The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters Sky Publishing Corporation Cambridge University Press ISBN 978 0 933346 51 2 a b c d e f g h i j NASA IPAC Extragalactic Database Results for Messier 081 Retrieved 6 November 2022 a b M 81 SIMBAD Centre de donnees astronomiques de Strasbourg Retrieved 28 November 2009 Armando Gil de Paz Boissier Samuel Madore Barry F Seibert Mark Joe Young H Boselli Alessandro Wyder Ted K Thilker David Bianchi Luciana Rey Soo Chang Rich R Michael Barlow Tom A Conrow Tim Forster Karl Friedman Peter G Martin D Christopher Morrissey Patrick Neff Susan G Schiminovich David Small Todd Donas Jose Heckman Timothy M Lee Young Wook Milliard Bruno Szalay Alex S Yi Sukyoung 2007 The GALEX Ultraviolet Atlas of Nearby Galaxies Astrophysical Journal 173 2 185 255 arXiv astro ph 0606440 Bibcode 2007ApJS 173 185G doi 10 1086 516636 S2CID 119085482 a b De Vaucouleurs Gerard De Vaucouleurs Antoinette Corwin Herold G Buta Ronald J Paturel Georges Fouque Pascal 1991 Third Reference Catalogue of Bright Galaxies Bibcode 1991rc3 book D Devereux N Ford H Tsvetanov Z Jocoby J 2003 STIS Spectroscopy of the Central 10 Parsecs of M81 Evidence for a Massive Black Hole Astronomical Journal 125 3 1226 1235 Bibcode 2003AJ 125 1226D doi 10 1086 367595 S2CID 121093306 a b c d O Meara S J 1998 The Messier Objects Cambridge University Press ISBN 978 0 521 55332 2 a b Starr Michelle 23 February 2022 Mysterious Repeating Fast Radio Burst Traced to Very Unexpected Location ScienceAlert Retrieved 24 February 2022 a b Kirsten F et al 23 February 2022 A repeating fast radio burst source in a globular cluster Nature 602 7898 585 589 arXiv 2105 11445 Bibcode 2022Natur 602 585K doi 10 1038 s41586 021 04354 w PMID 35197615 S2CID 235166402 Retrieved 24 February 2022 a b Jones K G 1991 Messier s Nebulae and Star Clusters 2nd ed Cambridge University Press ISBN 978 0 521 37079 0 a b c Eicher D J 1988 The Universe from Your Backyard Cambridge University Press ISBN 978 0 521 36299 3 Stephen Uitti Farthest Naked Eye Object Archived from the original on 19 August 2008 Retrieved 1 November 2008 a b Willner S P Ashby M L N Barmby P Fazio G G Pahre M Smith H A Kennicutt Jr R C Calzetti D Dale D A Draine B T Regan M W Malhotra S Thornley M D Appleton P N Frayer D Helou G Stolovy S Storrie Lombardi L 2004 Infrared Array Camera IRAC Observations of M81 Astrophysical Journal Supplement Series 154 1 222 228 arXiv astro ph 0405626 Bibcode 2004ApJS 154 222W doi 10 1086 422913 S2CID 16609000 a b c Gordon K D Perez Gonzalez P G Misselt K A Murphy E J Bendo G J Walter F Thornley M D Kennicutt Jr R C Rieke G H Engelbracht C W Smith J D T Alonso Herrero A Appleton P N Calzetti D Dale D A Draine B T Frayer D T Helou G Hinz J L Hines D C Kelly D M Morrison J E Muzerolle J Regan M W Stansberry J A Stolovy S R Storrie Lombardi L J Su K Y L Young E T 2004 Spatially Resolved Ultraviolet Ha Infrared and Radio Star Formation in M81 Astrophysical Journal Supplement Series 154 1 215 221 arXiv astro ph 0406064 Bibcode 2004ApJS 154 215G doi 10 1086 422714 S2CID 17283721 https science nasa gov mission hubble science explore the night sky hubble messier catalog messier 81 a b Perez Gonzalez P G Kennicutt Jr R C Gordon K D Misselt K A Gil De Paz A Engelbracht C W Rieke G H Bendo G J Bianchi L Boissier S Calzetti D Dale D A Draine B T Jarrett T H Hollenbach D Prescott M K M 2006 Ultraviolet through Far Infrared Spatially Resolved Analysis of the Recent Star Formation in M81 NGC 3031 Astrophysical Journal 648 2 987 1006 arXiv astro ph 0605605 Bibcode 2006ApJ 648 987P doi 10 1086 506196 S2CID 13901458 Chandar Rupali Whitmore Bradley Lee Myung Gyoon 10 August 2004 The Globular Cluster Systems of Five Nearby Spiral Galaxies New Insights from Hubble Space TelescopeImaging The Astrophysical Journal 611 1 220 244 arXiv astro ph 0407460 Bibcode 2004ApJ 611 220C doi 10 1086 421934 ISSN 0004 637X NASA IPAC Extragalactic Database Results for extended name search on NGC 3031 Retrieved 27 February 2007 Ripero J Garcia F Rodriguez D Pujol P Filippenko A V Treffers R R Paik Y Davis M Schlegel D Hartwick F D A Balam D D Zurek D Robb R M Garnavich P Hong B A 1993 Supernova 1993J in NGC 3031 IAU Circular 5731 1 Bibcode 1993IAUC 5731 1R a b c Schmidt B P Kirshner R P Eastman R G Grashuis R Dell Antonio I Caldwell N Foltz C Huchra John P Milone Alejandra A E 1993 The unusual supernova SN1993J in the galaxy M81 Nature 364 6438 600 602 Bibcode 1993Natur 364 600S doi 10 1038 364600a0 S2CID 4304547 a b c Filippenko A V Matheson T Ho L C 1993 The Type IIb Supernova 1993J in M81 A Close Relative of Type Ib Supernovae Astrophysical Journal Letters 415 L103 L106 Bibcode 1993ApJ 415L 103F doi 10 1086 187043 Benson P J Herbst W Salzer J J Vinton G Hanson G J Ratcliff S J Winkler P F Elmegreen D M Chromey F Strom C Balonek T J Elmegreen B G 1994 Light curves of SN 1993J from the Keck Northeast Astronomy Consortium Astronomical Journal 107 1453 1460 Bibcode 1994AJ 107 1453B doi 10 1086 116958 Wheeler J C Barker E Benjamin R Boisseau J Clocchiatti A De Vaucouleurs G Gaffney N Harkness R P Khokhlov A M Lester D F Smith B J Smith V V Tomkin J 1993 Early Observations of SN 1993J in M81 at McDonald Observatory Astrophysical Journal 417 L71 L74 Bibcode 1993ApJ 417L 71W doi 10 1086 187097 Richmond M W Treffers R R Filippenko A V Palik Y Leibundgut B Schulman E Cox C V 1994 UBVRI photometry of SN 1993J in M81 The first 120 days Astronomical Journal 107 1022 1040 Bibcode 1994AJ 107 1022R doi 10 1086 116915 Filippenko A V Matheson T Barth A J 1994 The peculiar type II supernova 1993J in M81 Transition to the nebular phase Astronomical Journal 108 2220 2225 Bibcode 1994AJ 108 2220F doi 10 1086 117234 Bishop David Extragalactic Novae supernovae net International Supernovae Network Archived from the original on 8 April 2010 Retrieved 11 September 2010 a b Karachentsev I D 2005 The Local Group and Other Neighboring Galaxy Groups Astronomical Journal 129 1 178 188 arXiv astro ph 0410065 Bibcode 2005AJ 129 178K doi 10 1086 426368 S2CID 119385141 a b c Yun M S Ho P T P Lo K Y 1994 A high resolution image of atomic hydrogen in the M81 group of galaxies Nature 372 6506 530 532 Bibcode 1994Natur 372 530Y doi 10 1038 372530a0 PMID 7990925 S2CID 4369085 Freedman Wendy 1994 The Hubble Space Telescope Extragalactic Distance Scale Project I The Discovery of Cepheids and a New Distance to M81 The Astrophysical Journal 427 June 628 655 Bibcode 1994ApJ 427 628F doi 10 1086 174172 via Astrophysics Data System External links edit nbsp Wikimedia Commons has media related to Messier 81 StarDate M81 Fact Sheet M81 SEDS Messier pages SST Messier 81 NASA Astronomy Picture of the Day Bright Galaxy M81 20 June 2002 NightSkyInfo com M81 Bode s Galaxy Messier 81 on WikiSky DSS2 SDSS GALEX IRAS Hydrogen a X Ray Astrophoto Sky Map Articles and images ESA Hubble images of M81 Galaxy Messier 81 Bode s Galaxy Spitzer Image Gallery Helkit Observatory Deep image of the M81 Area Bode s Galaxy at Constellation Guide Portals nbsp Astronomy nbsp Stars nbsp Outer space Retrieved from https en wikipedia org w index php title Messier 81 amp oldid 1211313959, wikipedia, wiki, book, books, library,

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