Local Group

Short description: Group of galaxies that includes the Milky Way

Local Group

Local Group of galaxies, including the massive members Messier 31 (Andromeda Galaxy) and Milky Way, as well as other nearby galaxies.

Observation data (Epoch J2000)
See also: Galaxy group, Galaxy cluster, List of galaxy groups and clusters

Distribution of the iron content (in logarithmic scale) in four neighbouring dwarf galaxies of the Milky Way

The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×1019 kilometres),[1] and a total mass of the order of 2×1012 solar masses (4×1042 kg).[2] It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda 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 of 123 km/s.[3] The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.

The two largest members, the Andromeda and the Milky Way galaxies, are both spiral galaxies with masses of about 1012 solar masses each. Each has its own system of satellite galaxies:

* The Andromeda Galaxy's satellite system consists of Messier 32 (M32), Messier 110 (M110), NGC 147, NGC 185, Andromeda I (And I), And II, And III, And V, And VI (also known as the Pegasus Dwarf Spheroidal Galaxy, or Pegasus dSph), And VII (a.k.a. the Cassiopeia Dwarf Galaxy), And VIII, And IX, And X, And XI, And XIX, And XXI and And XXII, plus several additional ultra-faint dwarf spheroidal galaxies.[4]
* The Milky Way's satellite galaxies system comprises the Sagittarius Dwarf Galaxy, Large Magellanic Cloud, Small Magellanic Cloud, Canis Major Dwarf Galaxy (disputed, considered by some not a galaxy), Ursa Minor Dwarf Galaxy, Draco Dwarf Galaxy, Carina Dwarf Galaxy, Sextans Dwarf Galaxy, Sculptor Dwarf Galaxy, Fornax Dwarf Galaxy, Leo I (a dwarf galaxy), Leo II (a dwarf galaxy), Ursa Major I Dwarf Galaxy and Ursa Major II Dwarf Galaxy, plus several additional ultra-faint dwarf spheroidal galaxies.[5]

Visual size comparison of the six largest Local Group galaxies, with details

The Triangulum 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.[6] It is unclear whether the Triangulum Galaxy is a companion of the Andromeda Galaxy; the two galaxies are 750,000 light years apart,[7] and experienced a close passage 2–4 billion years ago which triggered star formation across Andromeda's disk. The Pisces Dwarf Galaxy is equidistant from the Andromeda Galaxy and the Triangulum Galaxy, so it may be a satellite of either.[8]

The membership of NGC 3109, with its companions Sextans A and the Antlia Dwarf Galaxy, is uncertain due to extreme distances from the center of the Local Group.[3] 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, and Sagittarius Dwarf Irregular Galaxy.[9]

## Contents

* 1 History
* 2 Component galaxies
* 2.1 Map
* 2.2 List
* 2.3 Future
* 3 Other objects
* 4 See also
* 5 References
* 6 External links

## History

The term "The Local Group" was introduced by Edwin Hubble in Chapter VI of his 1936 book The Realm of the Nebulae.[10] 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 be M31, Milky Way, M33, Large Magellanic Cloud, Small Magellanic Cloud, M32, NGC 205, NGC 6822, NGC 185, IC 1613 and NGC 147. He also identified IC 10 as a possible part of the Local Group.

## Component galaxies

### Map

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Map of the Milky Way with directions of nearby galaxies marked (not to scale).

### List

Properties of galactic bodies in and around the Local Group[9] Name  | Type  | Constellation  | Notes

|
|
|

Spiral galaxies
Andromeda Galaxy (M31, NGC 224)  | SA(s)b  | Andromeda | Largest galaxy in the group[11]
Diameter (D25 isophote): 152,000 light-years
Mass: (1.5±0.5)×1012 M☉
Number of stars: ca. 1012.
Milky Way Galaxy | SBbc  | Sagittarius (centre)  | Second largest galaxy in the group, which may or may not be the most massive galaxy of the group.[12]
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)  | SA(s)cd  | Triangulum | Third largest, only unbarred spiral galaxy and possible satellite of the Andromeda Galaxy.
Diameter (D25 isophote): 60,000 light-years
Mass: 5×1010 M☉
Number of stars: 4×1010.
Magellanic spiral galaxies
Large Magellanic Cloud (LMC)  | Irr/SB(s)m  | Dorado | Fourth largest member of the group, satellite of Milky Way and only Magellanic Spiral Galaxy in the local group
Mass: 1×1010 M☉
Diameter (D25 isophote): 32,200 light-years
NGC 3109 | SB(s)m  | Hydra | Member of Antlia-Sextans Group
Elliptical galaxies
M32 (NGC 221)  | E2  | Andromeda  | Satellite of the Andromeda Galaxy, shows signs of a supermassive black hole
Irregular galaxies
Wolf–Lundmark–Melotte (WLM, DDO 221)  | Ir+  | Cetus | Possible size between Small Magellanic Cloud and Large Magellanic Cloud
IC 10 | KBm or Ir+  | Cassiopeia |
Small Magellanic Cloud (SMC, NGC 292)  | SB(s)m pec  | Tucana | Satellite of Milky Way, 6th largest galaxy in the local group

mass: 7 × 109 M☉

Pisces Dwarf (LGS3)  | Irr  | Pisces | Possible satellite of the Triangulum Galaxy
IC 1613 (UGC 668)  | IAB(s)m V  | Cetus |
Phoenix Dwarf  | Irr  | Phoenix |
Leo A (Leo III)  | IBm V  | Leo |
Aquarius Dwarf (DDO 210)  | IB(s)m  | Aquarius
SagDIG (Sagittarius Dwarf Irregular Galaxy)  | IB(s)m V  | Sagittarius | Most remote from barycenter member thought to be in the Local Group.[13]
NGC 6822 (Barnard's Galaxy)  | IB(s)m IV-V  | Sagittarius |
Pegasus Dwarf (Pegasus Dwarf Irregular, DDO 216)  | Irr  | Pegasus |
UGC 4879 (VV124)  | IAm  | Ursa Major | One of the most isolated galaxies in Local Group. Situated at the edge of the Local Group.
Sextans A (UGCA 205)  | Ir+V  | Sextans | Member of Antlia-Sextans Group
Sextans B (UGC 5373)  | Ir+IV-V  | Sextans | Member of Antlia-Sextans Group
Leo P  | Irr  | Leo | Member of Antlia-Sextans Group, extraordinarily low metallicity (Z = 0.03ZMW)
AGC 198606  | Irr?  | Leo | Gas-rich ultra-faint dwarf galaxy
AGC 215417  | Irr?  | Leo | Gas-rich ultra-faint dwarf galaxy
AGC 219656  | Irr?  | Leo | Gas-rich ultra-faint dwarf galaxy
AGC 249525  | Irr?  | Boötes | Gas-rich ultra-faint dwarf galaxy, Situated at the edge of the Local Group
AGC 268069  | Irr?  | Serpens | Gas-rich ultra-faint dwarf galaxy
Dwarf elliptical galaxies
M110 (NGC 205)  | dE6p  | Andromeda  | Satellite of the Andromeda Galaxy and 5th largest galaxy with the mass of 9.3 billion solar masses.
NGC 147 (DDO 3)  | dE5 pec  | Cassiopeia  | Satellite of the Andromeda Galaxy
Dwarf spheroidal galaxies
Boötes I | dSph  | Boötes |
Cetus Dwarf | dSph/E4  | Cetus  |
Canes Venatici I Dwarf and Canes Venatici II Dwarf | dSph  | Canes Venatici
Andromeda III | dE2  | Andromeda  | Satellite of the Andromeda Galaxy
NGC 185 | dE3 pec  | Cassiopeia  | Satellite of the Andromeda Galaxy
Andromeda I | dE3 pec  | Andromeda  | Satellite of the Andromeda Galaxy
Sculptor Dwarf (E351-G30)  | dE3  | Sculptor | Satellite of Milky Way
Andromeda V | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda II | dE0  | Andromeda  | Satellite of the Andromeda Galaxy
Fornax Dwarf (E356-G04)  | dSph/E2  | Fornax | Satellite of Milky Way
Carina Dwarf (E206-G220)  | dE3  | Carina | Satellite of Milky Way
Leo I (DDO 74)  | dE3  | Leo  | Satellite of Milky Way
Sextans Dwarf  | dE3  | Sextans  | Satellite of Milky Way
Leo II (Leo B)  | dE0 pec  | Leo  | Satellite of Milky Way
Ursa Minor Dwarf | dE4  | Ursa Minor | Satellite of Milky Way
Draco Dwarf (DDO 208)  | dE0 pec  | Draco | Satellite of Milky Way
SagDSG (Sagittarius Dwarf Spheroidal Galaxy)  | dSph/E7  | Sagittarius  | Satellite of Milky Way
Tucana Dwarf | dE5  | Tucana  |
Cassiopeia Dwarf (Andromeda VII)  | dSph  | Cassiopeia  | Satellite of the Andromeda Galaxy
Pegasus Dwarf Spheroidal Galaxy (Andromeda VI)  | dSph  | Pegasus  | Satellite of the Andromeda Galaxy
Ursa Major I Dwarf and Ursa Major II Dwarf | dSph  | Ursa Major | Satellite of Milky Way
Leo IV | dSph  | Leo | Satellite of the Milky Way
Leo V | dSph  | Leo | Satellite of the Milky Way
Leo T | dSph/Irr  | Leo | Satellite of the Milky Way
Boötes II | dSph  | Boötes | Satellite of the Milky Way
Boötes III | dSph  | Boötes | Satellite of the Milky Way
Boötes IV  | dSph  | Boötes | Satellite of the Milky Way
Coma Berenices | dSph  | Coma Berenices | Satellite of the Milky Way
Segue 2  | dSph  | Aries | Satellite of the Milky Way
Hercules | dSph  | Hercules | Satellite of the Milky Way
Pisces II | dSph  | Pisces | Satellite of the Milky Way
Reticulum II  | dSph  | Reticulum | Satellite of the Milky Way
Reticulum III  | dSph  | Reticulum  | Satellite of the Milky Way
Eridanus II | dSph  | Eridanus | Probable satellite of the Milky Way
Grus I  | dSph  | Grus | Satellite of the Milky Way
Grus II  | dSph  | Grus  | Satellite of the Milky Way
Tucana II  | dSph  | Tucana | Satellite of the Milky Way
Hydrus I  | dSph  | Hydrus  | Satellite of the Milky Way
Draco II  | dSph  | Draco  | Satellite of the Milky Way
Carina III  | dSph  | Carina  | Satellite of the Milky Way
Triangulum II (Laevens 2)  | dSph  | Triangulum  | Satellite of the Milky Way
Carina II  | dSph  | Carina  | Satellite of the Milky Way
Pictor II  | dSph  | Pictor | Satellite of the Milky Way
Horologium II  | dSph  | Horologium | Satellite of the Milky Way
Virgo I | dSph  | Virgo | Satellite of the Milky Way
Aquarius II  | dSph  | Aquarius  | Satellite of the Milky Way
Crater II | dSph  | Crater | Satellite of the Milky Way
Hydra II  | dSph  | Hydra  | Satellite of the Milky Way
Antlia II  | dSph  | Antlia  | Satellite of the Milky Way
Pegasus III  | dSph  | Pegasus  | Satellite of the Milky Way
Pegasus IV  | dSph  | Pegasus  | Satellite of the Milky Way[14]
Pegasus W  | dSph  | Pegasus | Recent star formation, could still be starforming
Cetus III  | dSph  | Cetus  | Satellite of the Milky Way
Tucana B  | dSph  | Tucana  | [15]
Perseus I Dwarf Galaxy (Andromeda XXXIII)  | dE  | Perseus | Satellite of Andromeda
Antlia Dwarf | dE3/dSph/Irr?  | Antlia  | Member of Antlia-Sextans Group
Andromeda IX | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda X | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XI | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XII  | dSph  | Andromeda  | Possible satellite of the Andromeda Galaxy
Andromeda XIII (Pisces III)  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XIV (Pisces IV)  | dSph  | Pisces  | Possible satellite of the Andromeda Galaxy
Andromeda XV  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XVII  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XIX | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XX  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XXI | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XXII | dSph  | Pisces  | Possible satellite of the Triangulum Galaxy
Andromeda XXIII  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XXIV  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XXV  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XXVI  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy
Andromeda XXVII  | dSph  | Andromeda  | Satellite of the Andromeda Galaxy, tidally disrupted[16]
Andromeda XXIX  | dSph  | Pegasus  | Satellite of the Andromeda Galaxy
Andromeda XXX (Cassiopeia II)  | dSph?  | Cassiopeia  | Satellite of the Andromeda Galaxy
Andromeda XXXI (Lacerta I)  | dSph?  | Lacerta  | Satellite of the Andromeda Galaxy
Andromeda XXXII (Cassiopeia III)  | dSph?  | Cassiopeia  | Satellite of the Andromeda Galaxy
Andromeda XXXIV (Pegasus V)  | dSph  | Pegasus  | Satellite of the Andromeda Galaxy[17]
Andromeda XVI (Pisces V)  | dSph  | Pisces  | Possible satellite of the Andromeda Galaxy
Andromeda XXVIII  | dSph?  | Pegasus  | Possible satellite of the Andromeda Galaxy
Andromeda XXXIII (Perseus I)  | dSph?  | Perseus  | Possible satellite of the Andromeda Galaxy
Andromeda XVIII | dSph  | Andromeda  |
Centaurus I  | dSph  | Centaurus  | Satellite of the Milky Way[18]
Pisces VII (Triangulum III)  | dSph?  | Pisces  | Candidate, possible satellite of the Triangulum Galaxy[19]
Identification unclear
Virgo Stellar Stream | dSph (remnant)?  | Virgo  | In the process of merging with the Milky Way
Canis Major Dwarf | Irr?  | Canis Major | Possibly a dwarf galaxy in the process of merging with the Milky Way
Hydra 1  |  | Hydra  | Possibly a dwarf galaxy in the process of merging with the Milky Way
Tucana III  | dSph or cluster?  | Tucana  | Satellite of the Milky Way, tidally disrupting
Tucana IV  | dSph or cluster?  | Tucana  | Satellite of the Milky Way
Tucana V  | dSph or cluster?  | Tucana  | Possibly non-existent
Columba I  | dSph or cluster?  | Columba | Satellite of the Milky Way
Segue 1 | dSph or Globular Cluster  | Leo  | Satellite of the Milky Way
Cetus II  |  | Cetus  | Likely part of Sagittarius tidal stream
Willman 1 | dSph or Globular Cluster  | Ursa Major  | 147,000 light-years away
Horologium I  | dSph or Globular Cluster  | Horologium  | Satellite of the Milky Way. Not to be confused with the Horologium Supercluster.
Pictoris  | dSph or Globular Cluster  | Pictor  | Satellite of the Milky Way
Phoenix II  | dSph or Globular Cluster  | Phoenix | Satellite of the Milky Way
Indus I (Kim 2)  | dSph or Globular Cluster  | Indus  | Satellite of the Milky Way
Eridanus III  | dSph or Globular Cluster  | Eridanus | Satellite of the Milky Way or SMC[20]
Sagittarius II  | dSph or Globular Cluster  | Sagittarius  | Satellite of the Milky Way
Andromeda VIII | dSph?  | Andromeda  | Satellite of the Andromeda Galaxy, tidally disrupting
Antlia B  |  | Antlia | Member of Antlia-Sextans Group
Probable non-members
Andromeda IV | Irr  | Andromeda  | Once 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).[21]
GR 8 (DDO 155)  | Im V  | Virgo | Distance 7.9 million light years[22]
IC 5152 | IAB(s)m IV  | Indus | Distance 5.8 million light years, possibly an outlying member of the local group[23]
NGC 300 | SA(s)d  | Sculptor | Distance 6.07 million light years
NGC 55 | SB(s)m  | Sculptor | Distance 6.5 million light years[24]
NGC 404 | E0 or SA(s)0− | Andromeda  | Distance 10 million light years[25]
NGC 1569 | Irp+ III-IV  | Camelopardalis  | In IC 342 group of galaxies. Distance 11 million light years[26]
NGC 1560 (IC 2062)  | Sd  | Camelopardalis  | Distance 8-12 million light years
Camelopardalis A  | Irr  | Camelopardalis  | Distance 12 million light years[24]
Argo Dwarf  | Irr  | Carina  |
ESO 347-8 (2318–42)  | Irr  | Grus |
UKS 2323-326 (ESO 407-18)  | Irr  | Sculptor  | Distance 7.2 million light-years[24]
UGC 9128 (DDO 187)  | Irp+  | Boötes  |
KKs 3 | dSph  | Hydrus |
Objects in the Local Group no longer recognised as galaxies
Palomar 12 (Capricornus Dwarf)  |  | Capricornus | Globular cluster formerly classified as a dwarf spheroidal galaxy
Palomar 4 (Ursa Major Dwarf)  |  | Ursa Major  | Globular cluster formerly classified as a dwarf spheroidal galaxy
Palomar 5 (Serpens Dwarf)  |  | Serpens | Globular cluster formerly classified as a dwarf spheroidal galaxy
Palomar 3 (Sextans C)  |  | Sculptor  | Globular cluster formerly classified as a dwarf spheroidal galaxy[27]
Segue 3 |  | Pegasus  | Globular cluster formerly classified as a dwarf spheroidal galaxy[28]
Laevens 1 (Crater Dwarf)  |  | Crater  | Globular cluster formerly classified as a dwarf spheroidal galaxy[29]
DES J2038-4609 (Indus II)  |  | Indus  | Likely a chance alignment of stars[30]

### Future

The galaxies of the Local Group are likely to merge together under their own mutual gravitational attractions over a timescale of tens of billions of years into a single elliptical galaxy, with the coalescence of Messier 31 and the Milky Way being the predominant event in this process.[31]

## Other objects

* 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 a stellar stream torn from the Canis Major Dwarf Galaxy

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

## See also

* Galaxy cluster
* IC 342/Maffei Group, the group of galaxies nearest to the Local Group
* List of galaxy groups and clusters
* List of nearest galaxies
* Virgocentric flow

## References

1. ↑ Redd, Nola Taylor (18 December 2017). "Astronomers track dwarf galaxies to better understand the Milky Way's make-up and evolution". Proceedings of the National Academy of Sciences 115 (51): 12836–12838. doi:10.1073/pnas.1817136115. PMID 30568025.
2. ↑ 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 with 1012 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☉.
3. ↑ 3.0 3.1 Karachentsev, 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. doi:10.1007/s10511-006-0002-6. Bibcode: 2006Ap.....49....3K.
4. ↑ Kalirai, Jason S.; Beaton, Rachael L.; Geha, Marla C.; Gilbert, Karoline M.; Guhathakurta, Puragra; Kirby, Evan N.; Majewski, Steven R.; Ostheimer, James C. et al. (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. doi:10.1088/0004-637X/711/2/671. ISSN 0004-637X. Bibcode: 2010ApJ...711..671K.
5. ↑ 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. doi:10.1088/0004-637X/805/2/130. Bibcode: 2015ApJ...805..130K.
6. ↑ "The Local Group". NASA. https://heasarc.gsfc.nasa.gov/docs/cosmic/local_group_info.html.
7. ↑ "Messier Object 33". https://www.messier.seds.org/m/m033.html.
8. ↑ Miller, Bryan W. et al. (December 2001). "The Star Formation History of LGS 3". The Astrophysical Journal 562 (2): 713–726. doi:10.1086/323853. ISSN 0004-637X. Bibcode: 2001ApJ...562..713M. http://stacks.iop.org/0004-637X/562/i=2/a=713.
9. ↑ 9.0 9.1 McConnachie, Alan W. (2012). "The observed properties of dwarf galaxies in and around the Local Group". The Astronomical Journal 144 (1): 4. doi:10.1088/0004-6256/144/1/4. Bibcode: 2012AJ....144....4M. http://www.astro.uvic.ca/~alan/Nearby_Dwarf_Database.html.
10. ↑ Hubble, E.P. (1936). The realm of the nebulae. Mrs. Hepsa Ely Silliman memorial lectures, 25. New Haven: Yale University Press. ISBN 9780300025002. OCLC 611263346. https://books.google.com/books?id=kgiXdDGLpFUC. Alt URL(pp. 124–151)
11. ↑ Kalirai, Jason S.; Beaton, Rachael L.; Geha, Marla C.; Gilbert, Karoline M.; Guhathakurta, Puragra; Kirby, Evan N.; Majewski, Steven R.; Ostheimer, James C. et al. (2018). "Evidence for an Intermediate-Mass Milky Way from Gaia DR2 Halo Globular Cluster Motions". The Astrophysical Journal 873 (2): 118. doi:10.3847/1538-4357/ab089f. Bibcode: 2019ApJ...873..118W.
12. ↑ Watkins, Laura L.; van der Marel, Roeland P.; Sohn, Sangmo Tony; Evans, N. Wyn (2019). "Evidence for an Intermediate-Mass Milky Way from Gaia DR2 Halo Globular Cluster Motions". The Astrophysical Journal 873 (2): 118. doi:10.3847/1538-4357/ab089f. Bibcode: 2019ApJ...873..118W.
13. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Bergh2000`
14. ↑ Cerny, W. et al. (2023). "Pegasus IV: Discovery and Spectroscopic Confirmation of an Ultra-faint Dwarf Galaxy in the Constellation Pegasus". The Astrophysical Journal 942 (2): 111. doi:10.3847/1538-4357/aca1c3. Bibcode: 2023ApJ...942..111C.
15. ↑ Sand, David J.; Mutlu-Pakdil, Burçin; Jones, Michael G.; Karunakaran, Ananthan; Wang, Feige; Yang, Jinyi; Chiti, Anirudh; Bennet, Paul et al. (2022). "Tucana B: A Potentially Isolated and Quenched Ultra-faint Dwarf Galaxy at D ≈ 1.4 MPC". The Astrophysical Journal Letters 935: L17. doi:10.3847/2041-8213/ac85ee.
16. ↑ Preston, Janet; Collins, Michelle L. M.; Ibata, Rodrigo A.; Tollerud, Erik J.; Rich, R. Michael; Bonaca, Ana; McConnachie, Alan W.; Mackey, Dougal et al. (2019). "A dwarf disrupting - Andromeda XXVII and the North West Stream". Monthly Notices of the Royal Astronomical Society 490 (2): 2905–2917. doi:10.1093/mnras/stz2529. Bibcode: 2019MNRAS.490.2905P.
17. ↑ Collins, Michelle L. M.; Charles, Emily J. E.; Martínez-Delgado, David; Monelli, Matteo; Karim, Noushin; Donatiello, Giuseppe; Tollerud, Erik J.; Boschin, Walter (2022). "Pegasus V/Andromeda XXXIV–a newly discovered ultrafaint dwarf galaxy on the outskirts of Andromeda". Monthly Notices of the Royal Astronomical Society: Letters 515 (1): L72–L77. doi:10.1093/mnrasl/slac063. Bibcode: 2022MNRAS.515L..72C.
18. ↑ Mau, S. (2020). "Two Ultra-faint Milky Way Stellar Systems Discovered in Early Data from the DECam Local Volume Exploration Survey". The Astrophysical Journal 890 (2): 136. doi:10.3847/1538-4357/ab6c67. Bibcode: 2020ApJ...890..136M.
19. ↑ Martínez-Delgado, David; Karim, Noushin; Charles, Emily J E.; Boschin, Walter; Monelli, Matteo; Collins, Michelle L M.; Donatiello, Giuseppe; Alfaro, Emilio J. (2022). "Pisces VII: Discovery of a possible satellite of Messier 33 in the DESI legacy imaging surveys". Monthly Notices of the Royal Astronomical Society 509 (1): 16–24. doi:10.1093/mnras/stab2797. Bibcode: 2022MNRAS.509...16M.
20. ↑ Conn, Blair C.; Jerjen, Helmut; Kim, Dongwon; Schirmer, Mischa (2018). "On the Nature of Ultra-faint Dwarf Galaxy Candidates. I. DES1, Eridanus III, and Tucana V". The Astrophysical Journal 852 (2): 68. doi:10.3847/1538-4357/aa9eda. Bibcode: 2018ApJ...852...68C.
21. ↑ Nowakowski, Tomasz (22 December 2015). "Andromeda IV turns out to be a solitary gas-rich dwarf galaxy". http://phys.org/news/2015-12-andromeda-iv-solitary-gas-rich-dwarf.html.
22. ↑ Tolstoy, Eline (1999). "Detailed Star-Formation Histories of Nearby Dwarf Irregular Galaxies using HST". in Patricia Whitelock. The stellar content of Local Group galaxies, Proceedings of the 192nd symposium of the International Astronomical Union. 192. Astronomical Society of the Pacific. 218. ISBN 978-1886733824. Bibcode: 1999IAUS..192..218T.
23. ↑ Ziljstra, A. A.; Minniti, Dante (April 1999). "A Dwarf Irregular Galaxy at the Edge of the Local Group: Stellar Populations and Distance of IC 5152". Astronomical Journal 117 (4): 1743–1757. doi:10.1086/300802. Bibcode: 1999AJ....117.1743Z.
24. ↑ 24.0 24.1 24.2 Tully, R. Brent (2013). "Cosmicflows-2: The Data". The Astronomical Journal 146 (4): 86. doi:10.1088/0004-6256/146/4/86. Bibcode: 2013AJ....146...86T.
25. ↑ Jensen, Joseph B.; Tonry, John L.; Barris, Brian J.; Thompson, Rodger I. et al. (February 2003). "Measuring Distances and Probing the Unresolved Stellar Populations of Galaxies Using Infrared Surface Brightness Fluctuations". Astrophysical Journal 583 (2): 712–726. doi:10.1086/345430. Bibcode: 2003ApJ...583..712J.
26. ↑ Grocholski, Aaron J.; Aloisi, Alessandra; van der Marel, Roeland P.; Mack, Jennifer et al. (20 October 2008). "A New Hubble Space Telescope Distance to NGC 1569: Starburst Properties and IC 342 Group Membership". Astrophysical Journal Letters 686 (2): L79–L82. doi:10.1086/592949. Bibcode: 2008ApJ...686L..79G.
27. ↑ "Pal3". http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Pal3&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id.
28. ↑ Fadely, R.; Willman, B.; Geha, M.; Walsh, S.; Muñoz, R. R.; Jerjen, H.; Vargas, L. C.; Da Costa, G. S. (2011). "Segue 3: An old, extremely low luminosity star cluster in the Milky Way's halo". The Astronomical Journal 142 (3): 88. doi:10.1088/0004-6256/142/3/88. Bibcode: 2011AJ....142...88F.
29. ↑ Voggel, Karina; Hilker, Michael; Baumgardt, Holger; Collins, Michelle L.M.; Grebel, Eva K.; Husemann, Bernd; Richtler, Tom; Frank, Matthias J. (2016). "Probing the boundary between star clusters and dwarf galaxies: A MUSE view on the dynamics of Crater/Laevens I". Monthly Notices of the Royal Astronomical Society 460 (3): 3384–3397. doi:10.1093/mnras/stw1132. Bibcode: 2016MNRAS.460.3384V.
30. ↑ Cantu, Sarah A. et al. (2021). "A Deeper Look at DES Dwarf Galaxy Candidates: Grus I and Indus II". The Astrophysical Journal 916 (2): 81. doi:10.3847/1538-4357/ac0443. Bibcode: 2021ApJ...916...81C.
31. ↑ Fred C. Adams; Gregory Laughlin (1997). "A dying universe: the long-term fate and evolution of astrophysical objects". Reviews of Modern Physics 69 (2): 337–372. doi:10.1103/RevModPhys.69.337. Bibcode: 1997RvMP...69..337A.

## External links

* "The Local Group". http://www.messier.seds.org/more/local.html.
* "Local Group Galaxies Survey". http://www2.lowell.edu/users/massey/lgsurvey/.
* van den Bergh, Sidney (2000). "Updated Information on the Local Group". The Publications of the Astronomical Society of the Pacific 112 (770): 529–536. doi:10.1086/316548. Bibcode: 2000PASP..112..529V.

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