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Local Sheet

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Nearby small galaxy filement
Local Sheet
The Local Sheet on the top view within 10 million light-years from Earth, including the Local Group and other nearby giant galaxies.
A portion of the Local Sheet, the Council of Giants, on the top view within 10 million light-years from Earth, including the Local Group and other nearby giant galaxies.
Observation data (Epoch J2000)
Number of galaxies14 (giant galaxies)[1]
Parent structureLocal Volume [1]
Major axis33.9 Mly (10.4 Mpc)[1]
Minor axis1.52 Mly (0.465 Mpc)[1]
Velocity dispersion 47 km/s [1]
Distance 420,700 ly (129 kpc) (center)[1]
ICM temperature 7.3×ばつ105 K [1]
Binding mass 1.6×ばつ1013[1]  M☉
Other designations
Local Street, Coma–Sculptor Cloud[1]
The 14 major galaxies, including Milky Way and Andromeda Galaxies, of the Local Sheet

The Local Sheet or the Coma–Sculptor Cloud is a nearby galaxy filament and an extragalactic region of space where the Milky Way, the members of the Local Group, and other galaxies share a similar peculiar velocity.[2] This region lies within a diameter of about 10.4 megaparsecs (34 million light-years; 3.2×ばつ1020 kilometres), 465 kiloparsecs (1.52 million light-years; 1.43×ばつ1019 kilometres) thick,[1] and galaxies beyond that distance show markedly different velocities.[3] The Local Group has only a relatively small peculiar velocity of 66 km⋅s−1 with respect to the Local Sheet. Typical velocity dispersion of galaxies is only 40 km⋅s−1 in the radial direction.[2] Nearly all nearby bright galaxies belong to the Local Sheet.[4] The Local Sheet is part of the Local Volume and is in the Virgo Supercluster (Local Supercluster).[1] The Local Sheet forms a wall of galaxies delineating one boundary of the Local Void.[5]

A significant component of the mean velocity of the galaxies in the Local Sheet appears as the result of the gravitational attraction of the Virgo Cluster of galaxies, resulting in a peculiar motion ~185 km⋅s−1 toward the cluster.[2] A second component is directed away from the center of the Local Void; an expanding region of space spanning an estimated 45 Mpc (150 Mly) that is only sparsely populated with galaxies.[3] This component has a velocity of 259 km⋅s−1.[2] The Local Sheet is inclined 8° from the Local Supercluster (Virgo Supercluster).[1]

The so-called Council of Giants is a ring of twelve large galaxies surrounding the Local Group in the Local Sheet, with a radius of 3.746 Mpc (12.22 Mly) and its center located at 810 kpc (2.6 Mly) away from the Sun.[1] Ten of these are spirals, while the remaining two are ellipticals. The two ellipticals (Maffei 1 and Centaurus A) lie on opposite sides of the Local Group.

Galaxies in the "Council of Giants"[1]
Catalog ID Name Constellation Distance (Mly) Stellar mass *
NGC 253 Sculptor Galaxy Sculptor 11 10.805
PGC 9892 Maffei 1 Cassiopeia 11 10.928
PGC 10217 Maffei 2 Cassiopeia 11 10.493
IC 342   Camelopardalis 11 10.302
NGC 3031 M 81 Ursa Major 12 10.905
NGC 3034 M 82 Ursa Major 11 10.573
NGC 4736 M 94 Canes Venatici 15 10.458
NGC 4826 M 64 Coma Berenices 16 10.496
NGC 5236 M 83 Hydra 16 10.642
NGC 5128 Centaurus A Centaurus 11 11.169
NGC 4945   Centaurus 12 10.528
ESO 97-G13 Circinus Galaxy Circinus 14 10.559
A portion of the Local Sheet within a map of 8 million light-years from Earth, including the Local Group and some other nearby galaxies.

* The mass is given as the logarithm (base unspecified) of the mass in solar masses.

Location

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The Local Sheet is the co-moving part of the Coma-Sculptor Cloud,[6] which was identified and described in 1987 by astronomer Brent Tully with colleague Richard Fisher in his book The Nearby Galaxies Atlas as Cloud 14.[7] It is a huge 10 Mpc (33 Mly) prolate,[8] filament[9] [10] [2] [8] and is mostly host to late-type galaxies, in contrast to the Virgo Cluster, in which more than half of the giant galaxies are early-type galaxies.[11]

Tully maintains that the Coma-Sculptor Cloud and the Local Sheet do not quite overlap,[2] as the Local Sheet comprises only the co-moving part of the Coma-Sculptor Cloud.[6] McCall considers the two terms synonymous, referring to one and the same region.[1]

See also

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References

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  1. ^ a b c d e f g h i j k l m n o McCall, Marshall L. (29 April 2013). "A Council of Giants". Monthly Notices of the Royal Astronomical Society. 440 (1) (published 10 March 2014): 405–426. arXiv:1403.3667 . Bibcode:2014MNRAS.440..405M. doi:10.1093/mnras/stu199 .
  2. ^ a b c d e f Tully, R. Brent; Shaya, Edward J.; Karachentsev, Igor D.; Courtois, Hélène M.; Kocevski, Dale D.; Rizzi, Luca; Peel, Alan (March 2008). "Our Peculiar Motion Away from the Local Void". The Astrophysical Journal. 676 (1): 184–205. arXiv:0705.4139 . Bibcode:2008ApJ...676..184T. doi:10.1086/527428. S2CID 14738309.
  3. ^ a b Tully, R. Brent (May 2008). "The Local Void is Really Empty". Proceedings of the International Astronomical Union. 244: 146–151. arXiv:0708.0864 . Bibcode:2008IAUS..244..146T. doi:10.1017/S1743921307013932. S2CID 119643726.
  4. ^ "Milky Way amidst a 'Council of Giants'". Science Daily. 11 March 2014.
  5. ^ Shaya, E. J.; Tully, R. B. (2013). "The formation of Local Group planes of galaxies". Monthly Notices of the Royal Astronomical Society. 436 (3): 2096–2119. arXiv:1307.4297 . Bibcode:2013MNRAS.436.2096S. doi:10.1093/mnras/stt1714 .
  6. ^ a b Tully, R. Brent (2008). "The Local Velocity Anomaly". Galaxies in the Local Volume. Astrophysics and Space Science Proceedings. Vol. 5. pp. 3–12. arXiv:0708.2449 . Bibcode:2008ASSP....5....3T. doi:10.1007/978-1-4020-6933-8_1. ISBN 978-1-4020-6932-1.
  7. ^ Tully, R. Brent; Fisher, J. Richard (1987). Atlas of Nearby Galaxies. Bibcode:1987ang..book.....T.
  8. ^ a b Müller, Oliver; Scalera, Roberto; Binggeli, Bruno; Jerjen, Helmut (June 2017). "The M 101 group complex: new dwarf galaxy candidates and spatial structure". Astronomy & Astrophysics. 602: A119. arXiv:1701.03681 . Bibcode:2017A&A...602A.119M. doi:10.1051/0004-6361/201730434. ISSN 0004-6361.
  9. ^ Tully, R. Brent; Verheijen, Marc A. W.; Pierce, Michael J.; Huang, Jia-Sheng; Wainscoat, Richard J. (December 1996). "The Ursa Major Cluster of Galaxies.I.Cluster Definition and Photometric Data". The Astronomical Journal. 112: 2471. arXiv:astro-ph/9608124 . Bibcode:1996AJ....112.2471T. doi:10.1086/118196. ISSN 0004-6256.
  10. ^ Hartwick, F. D. A. (May 2000). "The Structure of the Outer Halo of the Galaxy and its Relationship to Nearby Large-Scale Structure". The Astronomical Journal. 119 (5): 2248–2253. arXiv:astro-ph/9912083 . Bibcode:2000AJ....119.2248H. doi:10.1086/301332.
  11. ^ Burstein, D. (2000). "Elliptical galaxies dynamics: The issues pertaining to galaxy formation". In F. Hammer; T. X. Thuan; V. Cayatte; B. Guiderdoni; J. T. Thanh Van (eds.). Building Galaxies: From the Primordial Universe to the Present: Proceedings of the XIXth Rencontres de Moriond held at Les Arcs, March 13-20, 1999. World Scientific Publishing. p. 85. arXiv:astro-ph/9908355 . Bibcode:2000bgfp.conf...85B. ISBN 981-02-4411-8.

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