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Local Group

From Wikipedia, the free encyclopedia
Group of galaxies that includes the Milky Way

"Local group" redirects here. For other uses, seeLocal group (disambiguation).
Local Group
Local Group of galaxies, including the massive members Messier 31 (Andromeda Galaxy) and Milky Way, as well as other nearby galaxies. The center of the group is located between the two major galaxies.
Local Group of galaxies, including the massive membersMessier 31 (Andromeda Galaxy) and Milky Way, as well as othernearby galaxies. The center of the group is located between the two major galaxies.
Observation data (EpochJ2000)
ConstellationAndromeda (barycenter)[1]
Brightest memberAndromeda Galaxy[2]
Number of galaxies134+[1]
Parent structureLocal Sheet[3]
Major axis16.7 Mly (5.11 Mpc)[3]
Minor axis329,000 ly (101 kpc)[4]
Velocity dispersion49 km/s[5]
Distance1,458,000 ± 84,800 ly (447 ± 26 kpc) (barycenter)[1]
ICM temperature(2–3)×106 K[6]
Binding mass(2.47±0.15)×1012[1] M☉
Other designations
Local Galactic Group, Local group of galaxies, LG, [FWB89] GrG 282[7]
References: SIMBAD
A map of the Local Group with two subgroups of both Milky Way and Andromeda galaxies around its center
Distribution of the iron content (in logarithmic scale) in four neighbouring dwarf galaxies of the Milky Way

TheLocal Group is thegalaxy group that includes theMilky Way, whereEarth is located. It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and theAndromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kiloparsecs (3×10^6 ly; 2×1019 km) and are moving toward one another with a velocity of123 km/s.[8] Thecenter of the group is located at about 450 kpc (1.5 million ly) away from the Milky Way, placing it slightly closer to the Andromeda Galaxy by roughly 300 kpc (1 million ly), in which the latter may be more massive than the former in terms of mass.[1]

The Local Group has a total mass of the order of 2×1012solar masses (4×1042 kg),[9] and also a total diameter of 5.11megaparsecs (17 millionlight-years; 1.6×1020kilometres) based on density matching and the potential surface of its parent structure,Local Sheet.[3] It is itself a part of theLocal Volume and the largerVirgo Supercluster, which is a part of the even greaterLaniakea Supercluster along with thePisces–Cetus Supercluster Complex. The exact number of galaxies in the Local Group is unknown, as the Milky Way obscures some; however, a current total of 134 members is known within 1 megaparsec from the center, most of which aredwarf galaxies.[1] The Local Group was thought to have been more spread in theearly universe with 7megaparsecs (23 millionlight-years; 2.2×1020kilometres) by 700 million years after theBig Bang.[10]

The two largest members, the Andromeda and the Milky Way galaxies, are bothspiral galaxies with masses of about1012 solar masses each. Each has its own system ofsatellite galaxies:

Visual size comparison of the five largest Local Group galaxies along with the possible memberNGC 3109, with details

TheTriangulum Galaxy (M33) is the third-largest member of the Local Group, with a mass of approximately 5×1010 M☉ (1×1041 kg), and is the third spiral galaxy.[13] It is unclear whether the Triangulum Galaxy is a companion of the Andromeda Galaxy; the two galaxies are 750,000 light years apart,[14] and experienced a close passage 2–4 billion years ago which triggered star formation across Andromeda's disk. ThePisces Dwarf Galaxy is equidistant from the Andromeda Galaxy and the Triangulum Galaxy, so it may be a satellite of either.[15]

The other members of the group are likely gravitationally secluded from these large subgroups:IC 10,IC 1613,Phoenix Dwarf Galaxy,Leo A,Tucana Dwarf Galaxy,Cetus Dwarf Galaxy,Pegasus Dwarf Irregular Galaxy,Wolf–Lundmark–Melotte,Aquarius Dwarf Galaxy, andSagittarius Dwarf Irregular Galaxy.[16]

The membership ofNGC 3109, with its companionsSextans A and theAntlia Dwarf Galaxy as well asSextans B,Leo P,Antlia B and possiblyLeo A, is uncertain due to extreme distances from the center of the Local Group.[8] TheAntlia-Sextans Group is unlikely to be gravitationally bound to the Local Group due to probably lying outside the Local Group'szero-velocity surface—which would make it a true galaxy group of its own rather than a subgroup within the Local Group.[17] This possible independence may, however, disappear as the Milky Way continues coalescing with Andromeda due to the increased mass, and density thereof, plausibly widening the radius of the zero-velocity surface of the Local Group.

History

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The term "The Local Group" was introduced byEdwin Hubble in Chapter VI of his 1936 bookThe Realm of the Nebulae.[18] There, he described it as "a typical small group of nebulae which is isolated in the general field" and delineated, by decreasing luminosity, its members to beM31,Milky Way,M33,Large Magellanic Cloud,Small Magellanic Cloud,M32,NGC 205,NGC 6822,NGC 185,IC 1613 andNGC 147. He also identifiedIC 10 as a possible part of the Local Group.

Component galaxies

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Clickable map

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Map of the local universe within 5 million light-years from Earth, including the Local Group and other nearby galaxies (clickable map)

List

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Properties of galactic bodies in and around the Local Group[16]
NameTypeConstellationNotes
Spiral galaxies
Andromeda Galaxy (M31, NGC 224)SAbAndromedaLargest galaxy in the group[19]
Diameter (D25 isophote): 152,000 light-years
Mass:(1.5±0.5)×1012 M☉
Number of stars: ca.1012.
Milky Way GalaxySBbcSagittarius (centre)Second largest galaxy in the group, which may or may not be the most massive galaxy of the group.[20]
Diameter (D25 isophote): 87,400 light-years
Mass:(1.54±0.1)×1012 M☉
Number of stars:(2.5±1.5)×1011.
Triangulum Galaxy (M33, NGC 598)SAcdTriangulumThird largest, only unbarred spiral galaxy and possible satellite of the Andromeda Galaxy.
Diameter (D25 isophote): 61,100 light-years
Mass:5×1010 M☉
Number of stars:4×1010.
Magellanic spiral galaxies
Large Magellanic Cloud (LMC, Dorado Dwarf)Irr/SB(s)mDoradoFourth largest known member of the group, satellite of Milky Way and only confirmed Magellanic Spiral Galaxy in the local group
Mass:1×1010 M☉
Diameter (D25 isophote): 32,200 light-years
Elliptical galaxies
M32 (NGC 221, Andromeda Dwarf)cE2AndromedaSatellite of the Andromeda Galaxy, shows signs of a supermassive black hole
Irregular galaxies
Wolf–Lundmark–Melotte (WLM, DDO 221)Ir+CetusPossible size betweenSmall Magellanic Cloud andLarge Magellanic Cloud
IC 10 (Cascopea IV, PGC 4774942-40+4)KBm or Ir+CassiopeiaOnly known starbust galaxy in the Local Group
Small Magellanic Cloud (SMC, NGC 292, Tucana galaxy)SB(s)m pecTucanaSatellite of Milky Way, 5th largest known galaxy in the local group
Mass:7×109 M☉
Diameter (D25 isophote): 18,900 light-years
Pisces Dwarf (LGS3,Pisces I dwarf irregular)IrrPiscesPossible satellite of the Triangulum Galaxy
IC 1613 (UGC 668, UGCA 47954)IAB(s)m VCetus
Phoenix Dwarf (Phoenix I dwarf)IrrPhoenix
Leo A (Leo III, PCA QA JO74974)IBm VLeo
Aquarius Dwarf (DDO 210, Aquarius I, ESO 497-4054.4591 G)IB(s)mAquariusDistance 3.2 million light years. Quite isolated in space, membership to Local Group established in 1999.[21]
SagDIG (Sagittarius Dwarf Irregular Galaxy, Sagittarius II)IB(s)m VSagittariusMost remote frombarycenter member thought to be in the Local Group.[21]
NGC 6822 (Barnard's Galaxy, AO 4797)IB(s)m IV-VSagittarius
Pegasus Dwarf (Pegasus Dwarf Irregular, DDO 216)IrrPegasus
UGC 4879 (VV124)IAmUrsa MajorOne of the most isolated galaxies in Local Group. Situated at the edge of the Local Group.
Sextans A (UGCA 205, AO 4977)Ir+VSextansMember ofAntlia-Sextans Group
Sextans B (UGC 5373, QRT 947748)Ir+IV-VSextansMember ofAntlia-Sextans Group
Leo P (AGC 19470059)IrrLeoMember ofAntlia-Sextans Group, extraordinarily low metallicity (Z = 0.03ZMW)
AGC 198606 (Leo VI)Irr?LeoGas-rich ultra-faint dwarf galaxy
AGC 215417(Leo VII)Irr?LeoGas-rich ultra-faint dwarf galaxy
AGC 219656Irr?LeoGas-rich ultra-faint dwarf galaxy
AGC 249525Irr?BoötesGas-rich ultra-faint dwarf galaxy, Situated at the edge of the Local Group
AGC 268069Irr?SerpensGas-rich ultra-faint dwarf galaxy
Dwarf elliptical galaxies
M110 (NGC 205)dE6pAndromedaSatellite of the Andromeda Galaxy and the 6th largest galaxy with the mass of 9.3 billion solar masses.
NGC 147 (DDO 3)dE5 pecCassiopeiaSatellite of the Andromeda Galaxy
Dwarf spheroidal galaxies
Boötes I (DDO 9774998.074÷×47)dSphBoötessatellite of the Milky Way
Cetus DwarfdSph/E4Cetus3.4 million light-years away

size:999 light-years

Canes Venatici I Dwarf andCanes Venatici II DwarfdSphCanes VenaticiSatellites of the Milky Way[22][23]
Andromeda IIIdE2AndromedaSatellite of the Andromeda Galaxy
NGC 185dE3 pecCassiopeiaSatellite of the Andromeda Galaxy
Andromeda IdE3 pecAndromedaSatellite of the Andromeda Galaxy
Sculptor Dwarf (E351-G30)dE3SculptorSatellite of Milky Way
Andromeda V (UKS 4977-94)dSphAndromedaSatellite of the Andromeda Galaxy
Andromeda II (NCA 14)dE0AndromedaSatellite of the Andromeda Galaxy
Fornax Dwarf (E356-G04)dSph/E2FornaxSatellite of Milky Way
Carina Dwarf (E206-G220)dE3CarinaSatellite of Milky Way
Leo I (DDO 74)dE3LeoSatellite of Milky Way
Sextans Dwarf (Sextans 1)dE3SextansSatellite of Milky Way
Leo II (Leo B)dE0 pecLeoSatellite of Milky Way
Ursa Minor Dwarf (NCA 47-49)dE4Ursa MinorSatellite of Milky Way
Draco Dwarf (DDO 208)dE0 pecDracoSatellite of Milky Way
SagDSG (Sagittarius Dwarf Spheroidal Galaxy)dSph/E7SagittariusSatellite of Milky Way
Tucana DwarfdE5Tucana3.2 million ly away
Cassiopeia Dwarf (Andromeda VII, NCA 4)dSphCassiopeiaSatellite of the Andromeda Galaxy
Pegasus Dwarf Spheroidal Galaxy (Andromeda VI)dSphPegasusSatellite of the Andromeda Galaxy
Ursa Major I DwarfdSphUrsa MajorSatellite of the Milky Way
Ursa Major II DwarfdSphUrsa MajorSatellite of the Milky Way
Ursa Major IIIdSphUrsa MajorSatellite of the Milky Way
Leo IVdSphLeoSatellite of the Milky Way
Leo VdSphLeoSatellite of the Milky Way
Leo TdSph/IrrLeoSatellite of the Milky Way
Boötes IIdSphBoötesSatellite of the Milky Way
Boötes III (NCA 4.9)dSphBoötesSatellite of the Milky Way, Bootes lll likely formed both the Bootes Ill Stream & the Monosoros Stellar stream
Boötes IVdSphBoötesSatellite of the Milky Way
Coma BerenicesdSphComa BerenicesSatellite of the Milky Way
Segue 2 (Aries Dwarf, NCA 429)dSphAriesSatellite of the Milky Way

size:220 light-yearsnumber of stars:≈1000

Hercules (NCA 4977429)dSphHerculesSatellite of the Milky Way
Pisces IIdSphPiscesSatellite of the Milky Way
Reticulum IIdSphReticulumSatellite of the Milky Way
Reticulum IIIdSphReticulumSatellite of the Milky Way
Eridanus IIdSphEridanusProbable satellite of the Milky Way
Grus IdSphGrusSatellite of the Milky Way
Grus IIdSphGrusSatellite of the Milky Way
Tucana IIdSphTucanaSatellite of the Milky Way
Hydrus I (Hydrus Dwarf spheroidal galaxy)dSphHydrusSatellite of the Milky Way
Draco IIdSphDracoSatellite of the Milky Way
Carina IIIdSphCarinaSatellite of the Milky Way
Triangulum II (Laevens 2)dSphTriangulumSatellite of the Milky Way
Carina IIdSphCarinaSatellite of the Milky Way
Pictor IIdSphPictorSatellite of the Milky Way
Horologium IIdSphHorologiumSatellite of the Milky Way
Virgo IdSphVirgoSatellite of the Milky Way
Virgo IIIdSph?VirgoSatellite of the Milky Way[24]
Sextans IIdSph?SextansSatellite of the Milky Way[24]
Aquarius IIdSphAquariusSatellite of the Milky Way
Aquarius IIIdSph?AquariusSatellite of the Milky Way[25]
Crater IIdSphCraterSatellite of the Milky Way
Hydra IIdSphHydraSatellite of the Milky Way
Antlia IIdSphAntliaSatellite of the Milky Way
Pegasus IIIdSphPegasusSatellite of the Milky Way
Pegasus IVdSphPegasusSatellite of the Milky Way[26]
Pegasus WdSphPegasusRecent star formation, could still be starforming
Cetus IIIdSphCetusSatellite of the Milky Way
Leo KdSph?LeoSatellite of the Milky Way[27]
Leo MdSph?LeoSatellite of the Milky Way[27]
Leo VIdSphLeoSatellite of the Milky Way[28]
Leo Minor IdSph?Leo MinorSatellite of the Milky Way[29]
Boötes VdSph?BoötesSatellite of the Milky Way[29]
Virgo IIdSph?VirgoSatellite of the Milky Way[29]
Tucana BdSphTucana[30]
DES 1dEPerseusSatellite of Milky Way
Antlia DwarfdE3/dSph/Irr?AntliaMember ofAntlia-Sextans Group
Andromeda IXdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XIdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XIIdSphAndromedaPossible satellite of the Andromeda Galaxy
Andromeda XIII (Pisces III)dSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XIV (Pisces IV)dSphPiscesPossible satellite of the Andromeda Galaxy
Andromeda XVdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XVIIdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XIXdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXIdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXIIdSphPiscesPossible satellite of the Triangulum Galaxy
Andromeda XXIIIdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXIVdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXVdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXVIdSphAndromedaSatellite of the Andromeda Galaxy
Andromeda XXVIIdSphAndromedaSatellite of the Andromeda Galaxy, tidally disrupted[31]
Andromeda XXIXdSphPegasusSatellite of the Andromeda Galaxy
Andromeda XXX (Cassiopeia II)dSph?CassiopeiaSatellite of the Andromeda Galaxy
Andromeda XXXI (Lacerta I)dSph?LacertaSatellite of the Andromeda Galaxy
Andromeda XXXII (Cassiopeia III)dSph?CassiopeiaSatellite of the Andromeda Galaxy
Andromeda XXXIV (Pegasus V)dSphPegasusSatellite of the Andromeda Galaxy[32]
Andromeda XXXVdSphAndromedaSatellite of the Andromeda Galaxy[33]
Andromeda XVI (Pisces V)dSphPiscesPossible satellite of the Andromeda Galaxy
Andromeda XXVIIIdSph?PegasusPossible satellite of the Andromeda Galaxy
Andromeda XXXIII (Perseus I)dSph?PerseusPossible satellite of the Andromeda Galaxy
Andromeda XVIIIdSphAndromeda
Centaurus IdSphCentaurusSatellite of the Milky Way[34]
Pisces VII (Triangulum III)dSph?PiscesCandidate, possible satellite of the Triangulum Galaxy[35]
Identification unclear
Virgo Stellar StreamdSph (remnant)?VirgoIn the process of merging with the Milky Way
Canis Major DwarfIrr?Canis MajorPossibly a dwarf galaxy in the process of merging with the Milky Way
Hydra 1HydraPossibly a dwarf galaxy in the process of merging with the Milky Way
Tucana IIIdSph or cluster?TucanaSatellite of the Milky Way, tidally disrupting
Tucana IVdSph or cluster?TucanaSatellite of the Milky Way
Tucana VdSph or cluster?TucanaPossibly non-existent
Columba IdSph or cluster?ColumbaSatellite of the Milky Way
Segue 1dSph or Globular ClusterLeoSatellite of the Milky Way
Cetus IICetusLikely part of Sagittarius tidal stream
Willman 1dSph or Globular ClusterUrsa Major147,000 light-years away
Horologium IdSph or Globular ClusterHorologiumSatellite of the Milky Way. Not to be confused with the Horologium Supercluster.
PictorisdSph or Globular ClusterPictorSatellite of the Milky Way
Phoenix IIdSph or Globular ClusterPhoenixSatellite of the Milky Way
Indus I (Kim 2, Indus Dwarf)dSph or Globular ClusterIndusSatellite of the Milky Way
Eridanus IIIdSph or Globular ClusterEridanusSatellite of the Milky Way or SMC[36]
Sagittarius IIdSph or Globular ClusterSagittariusSatellite of the Milky Way
Andromeda VIII (Adsant-40-7 quote serp galaxy)dSph?AndromedaSatellite of the Andromeda Galaxy, tidally disrupting
Antlia BAntliaMember ofAntlia-Sextans Group
Probable non-members
NGC 3109 (Antlia Sextans galaxy l)SB(s)mHydraMember ofAntlia-Sextans Group, it would be the 4th largest member if part of the Local Group
Mass:2.3×109 M☉
Diameter (D25.5 isophote): 41,700 light-years
Andromeda IVIrrAndromedaOnce considered to be associated with M31. Its distance is now known to be 22 to 24 million light years (not close to the Andromeda Galaxy at all).[37]
GR 8 (DDO 155)Im VVirgoDistance 7.9 million light years[38]
IC 5152 (Indus III)IAB(s)m IVIndusDistance 5.8 million light years, possibly an outlying member of the Local Group[39]
KK 153Ursa MajorDistance 6.5 million light years, possibly an outlying member of the Local Group[40]
NGC 300SA(s)dSculptorDistance 6.07 million light years
NGC 55SB(s)mSculptorDistance 6.5 million light years[41]
NGC 404E0 or SA(s)0−AndromedaDistance 10 million light years[42]
NGC 1569 (IC 49447)Irp+ III-IVCamelopardalisInIC 342 group of galaxies. Distance 11 million light years[43]
NGC 1560 (IC 2062)SdCamelopardalisDistance 8-12 million light years
Camelopardalis AIrrCamelopardalisDistance 12 million light years[41]
Argo DwarfIrrCarina7.1 million light-years away
ESO 347-8 (2318–42, PGC 475744)IrrGrus9 million light-years away fairly isolated until million light years. away from the galaxy
UKS 2323-326 (ESO 407-18)IrrSculptorDistance 7.2 million light-years[41]
UGC 9128 (DDO 187)Irp+Boötes7 million light-years away
KKs 3 (Hydrus II)dSphHydrusDistance 5.2 million light-years
Objects in the Local Group no longer recognised as galaxies
Palomar 12 (Capricornus Dwarf)dSphrCapricornusGlobular cluster formerly classified as a dwarf spheroidal galaxy
Palomar 4 (Ursa Major Dwarf)d SphrUrsa MajorGlobular cluster formerly classified as a dwarf spheroidal galaxy
Palomar 5 (Serpens Dwarf)SerpensGlobular cluster formerly classified as a dwarf spheroidal galaxy
Palomar 3 (Sextans C)SculptorGlobular cluster formerly classified as a dwarf spheroidal galaxy[44]
Segue 3PegasusGlobular cluster formerly classified as a dwarf spheroidal galaxy[45]
Laevens 1 (Crater Dwarf)CraterGlobular cluster formerly classified as a dwarf spheroidal galaxy[46]
DES J2038-4609 (Indus II)IndusLikely a chance alignment of stars[47]
NameTypeConstellationNotes

Structure

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Overview of the structure and trajectory of the Local Group

Streams

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  • Magellanic Stream, a stream of gas being stripped off the Magellanic Clouds due to their interaction with the Milky Way
  • Monoceros Ring, a ring of stars around the Milky Way that is proposed to consist of astellar stream torn from the Canis Major Dwarf Galaxy
  • Virgo Stream, a stream formed from a dwarf galaxy.
  • Helmi Stream

Future

[edit]
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Find sources: "Local Group" – news ·newspapers ·books ·scholar ·JSTOR(November 2025)
ANASA conception of the collision usingcomputer-generated imagery

The galaxies of the Local Group are likely to merge together under their own mutual gravitational attractions over a timescale oftens of billions of years into a singleelliptical galaxy, with thecoalescence of Andromeda and the Milky Way being the predominant event in this process.[48]There is debate over whether ellipticity might be the immediate structure of the combined galaxy right after the collision or whether ellipticity might only emerge after a theoretical intermediate period of retaining a spiraling structure directly following the collision. Some even theorize a permanent superspiral or a transition toward a morelenticular galaxy, rather than a more elliptical or spiraled distribution, as the future of the Local Group's galactic merger.

Location

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Main article:Laniakea Supercluster
This paragraph is an excerpt fromLaniakea Supercluster.[edit]

TheLaniakea Supercluster or Laniakea for short (/ˌlɑːni.əˈkeɪ.ə/;Hawaiian for "open skies" or "immense heaven")[49] is thelarge-scale structure centered around theGreat Attractor that is home to theMilky Way and approximately 100,000 other nearby galaxies. It was originally defined in September 2014 as agalaxysupercluster, when a group of astronomers, includingR. Brent Tully of theUniversity of Hawaiʻi at Mānoa,Hélène Courtois of theUniversity of Lyon, Yehuda Hoffman of theHebrew University of Jerusalem, andDaniel Pomarède of CEAUniversité Paris-Saclay published a new way of defining superclusters according to therelative velocities of galaxies as basins of attraction.[50][51] The new definition of the Local Supercluster[52][53] subsumes the then prior definedVirgo andHydra-Centaurus Supercluster as appendages, the former being the historical local supercluster.[54][55][52][56][53]

A diagram of our location in theobservable universe. (Alternative image.)

See also

[edit]

References

[edit]
  1. ^abcdefMakarov, Danila; Makarov, Dmitry; Makarova, Lidia; Libeskind, Noam (2025). "The frozen outskirts: A cold Hubble flow and the mass of the Local Group".Astronomy & Astrophysics.698: A178.arXiv:2505.06642.Bibcode:2025A&A...698A.178M.doi:10.1051/0004-6361/202554778.
  2. ^Theuns, Tom."Galaxy population".Institute for Computational Cosmology.Durham University.
  3. ^abcMcCall, 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.
  4. ^Banik, Indranil; Zhao, Hongsheng (2018)."A plane of high-velocity galaxies across the Local Group".Monthly Notices of the Royal Astronomical Society.473 (3):4033–4054.arXiv:1701.06559.doi:10.1093/mnras/stx2596.
  5. ^Elahi, Pascal J.; Power, Chris; Lagos, Claudia del P.; Poulton, Rhys; Robotham, Aaron S G. (2018)."Using velocity dispersion to estimate halo mass: Is the Local Group in tension with ΛCDM?".Monthly Notices of the Royal Astronomical Society.477:616–623.arXiv:1712.01989.doi:10.1093/mnras/sty590.
  6. ^Maloney, Philip R.; Bland-Hawthorn, J. (1999). "Warm Gas and Ionizing Photons in the Local Group".The Astrophysical Journal.522 (2):L81–L84.arXiv:astro-ph/9907197.Bibcode:1999ApJ...522L..81M.doi:10.1086/312223.
  7. ^{{{label}}}
  8. ^abKarachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field".Astrophysics.49 (1):3–18.Bibcode:2006Ap.....49....3K.doi:10.1007/s10511-006-0002-6.S2CID 120973010.
  9. ^The mass of the Local Group is essentially accounted for by the mass of the Milky Way and the Andromeda Galaxy.Estimates for the mass of each galaxy are compatible with1012 M☉, and Peñarrubia et al. (2014) estimate(2.3±0.7)×1012 M☉ for the Local Group,but Karachentsev and Kashibadze (2006) estimate the somewhat lower value of(1.29±0.14)×1012 M☉.
  10. ^Boylan-Kolchin, Michael; Weisz, Daniel R.; Bullock, James S.; Cooper, Michael C. (2016)."The Local Group: The ultimate deep field".Monthly Notices of the Royal Astronomical Society: Letters.462:L51–L55.arXiv:1603.02679.doi:10.1093/mnrasl/slw121.
  11. ^Kalirai, Jason S.; Beaton, Rachael L.;Geha, Marla C.; Gilbert, Karoline M.; Guhathakurta, Puragra; Kirby, Evan N.; Majewski, Steven R.; Ostheimer, James C.; Patterson, Richard J. (17 February 2010). "The Splash Survey: Internal Kinematics, Chemical Abundances, and Masses of the Andromeda I, Ii, III, Vii, X, and Xiv Dwarf Spheroidal Galaxies".The Astrophysical Journal.711 (2):671–692.arXiv:0911.1998.Bibcode:2010ApJ...711..671K.doi:10.1088/0004-637X/711/2/671.ISSN 0004-637X.S2CID 43188686.
  12. ^Sergey E. Koposov; Vasily Belokurov; Gabriel Torrealba; N. Wyn Evans (10 March 2015). "Beasts of the Southern Wild. Discovery of a large number of Ultra Faint satellites in the vicinity of the Magellanic Clouds".The Astrophysical Journal.805 (2): 130.arXiv:1503.02079.Bibcode:2015ApJ...805..130K.doi:10.1088/0004-637X/805/2/130.S2CID 118267222.
  13. ^"The Local Group".NASA's High Energy Astrophysics Science Archive Research Center (HEASARC).NASA. Retrieved5 May 2015.
  14. ^"Messier Object 33".www.messier.seds.org. Archived fromthe original on 29 June 2023. Retrieved21 May 2021.
  15. ^Miller, Bryan W.; et al. (December 2001)."The Star Formation History of LGS 3".The Astrophysical Journal.562 (2):713–726.arXiv:astro-ph/0108408.Bibcode:2001ApJ...562..713M.doi:10.1086/323853.ISSN 0004-637X.S2CID 119089499.
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