The Local Group

The Local Group of Galaxies (LG) is a small but diverse collection of different types of galaxies: First the three big spirals (S) - our Milky Way (MW), the Andromeda Galaxy M31, and the Triangulum Galaxy M33, itself maybe a satellite of M31. Then there are some elliptical (E) and irregular (I or S[B]m) galaxies, as satellites of the big ones or field members of the Local Group. Furthermore there is the small formation of dwarf galaxies around NGC 3109, which may or may not be members of the LG.

And then there are the little ones: plenty of dwarf spheroidal (dSph) and only recently discovered ultra faint dwarf (UFD) galaxies at the lower size limit toward globular clusters. Not to forget the many less observable features as gaseous and dark matter halos and stellar tidal streams.

With this chart here I tried to show all the discovered galactic members of the Local Group as seen from Earth, with known (or at least suspected) subgroups color-coded (see below). Because of the concentration of satellites around M31 the complete galaxy names are only visible at higher zoom level. Rotate the view with mouse- or fingertip-dragging, zoom with mouse wheel or pinch, depending on what kind of interface you are using. The source for the underlying map can be found at my Github repository.

The equatorial yellow line is the galactic plane and the pink line is the supergalactic plane.

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Subgroups:
Milky Way
M31(Andromeda)
NGC 3109
Galaxy Types:
Spiral
Elliptical
Irregular

Dwarf Spheroidal (dSph)
Ultra Faint Dwarf (UFD)

In the last decade many discoveries have improved our picture of the Local Group. In particular the Sloan Digital Sky survey (SDSS) and the PAndAS survey (Pan-Andromeda Archaeological Survey) have enabled many discoveries of very faint objects, while infrared surveys continue to search through the galactic plane to find objects so far hidden behind it. The SDSS has for the most part only probed the northern hemisphere, so there may also lurk many undiscovered dSphs and UFDs in the southern hemisphere.

As the count stands so far, there are 87 members of the Local Group so far and 7 probables. 32 are satellites of the Milky Way, 42 of M31. The census by morphological type: 9 spirals, 5 ellipticals, 18 irregulars, 41 dwarf spheroidals and 21 UFDs. Below is a list with data of all members and candidates:

Name         Alt. Name  l      b      M      Rh     Dh      Dnear   Metal.  Type      Subgroup
                        °      °      mag    pc     kpc     kpc     [Fe/H]                    
Milky Way    GC          0      0    -20.9            8.5   460             SABbc I-II   MW  
Sgr I        SagDEG      5.57 -14.16 -13.8  1550     24.0    16.0   -0.5    dSph(t)      MW  
UKS2323-326  UGCA 438   11.87 -70.86 -13.1          770    1350             IBm V-VI pec LG??
SagDIG       Sgr dw     21.06 -16.28 -10.7          930    1180     -2.3    IBm V-VI:    LG  
NGC 6822     DDO 209    25.35 -18.38 -16.0          490     670     -1.2    IBm V-VI     LG  
Boö III                 27.39  55.43  -5.8   170     46.0    44.0   -2.1    UFD?         MW  
Her I                   28.73  36.87  -6.2   330    138.0   134.2   -2.41   UFD          MW  
Aqr I        DDO 210    34.05 -31.34 -11.3   216    565     960     -1.0    IBm V-VI     LG  
CVn I                   74.31  79.82  -7.9   564    220.0   219.8   -1.98   dSph         MW  
WLM          DDO 221    75.86 -73.62 -14.4   917   1122     810     -0.87   IBm V-VI     LG  
Psc II                  79.21 -47.11  -5.0    60    180     180             UFD          MW  
Dra I        DDO 208    86.37  34.72  -8.6   196     82      82     -1.93   dSph pec     MW  
And XXVIII              91.03 -22.93  -8.5   210    650     365     -2.0    dSph         M31 
PegDIG       DDO 216    94.78 -43.55 -12.3          783     410     -1.5    Im V-VI      M31?
Lac I        And XXXI  101.1  -16.7  -11.7   912    756     275             dSph         M31 
Cet I        KKS 1     101.46 -72.85 -10.1   590    755     620     -1.7    dSph         LG  
UMi I        DDO 199   104.97  44.80  -8.9   280     66.0    68.0   -2.13   dSph         MW  
Peg I        And VI    106.04 -36.32 -10.6   424    919     265     -1.7    dSph         M31 
Cas I        And VII   109.46  -9.95  -9.5   740    763     215     -1.5    dSph         M31 
And XXIX               109.80 -30.77  -8.3   360    730     207     -1.8    dSph         M31 
And XXI                111.9  -19.2   -9.8   842    827     135     -1.8    dSph         M31 
And XX                 112.9  -26.9   -6.3   114    741     128     -1.5    UFD          M31 
CVn II                 113.58  82.70  -4.8    74    151.0   150.7   -2.21   UFD          MW  
And XVIII              113.9  -16.9   -9.7   325   1214     357     -1.8    dSph         M31?
And XIX                115.6  -27.4   -9.6  1481    821     115     -1.9    dSph         M31 
And XXVI               118.1  -14.7   -7.1   219    754     103     -1.9    dSph         M31 
IC 10                  118.96  -3.33 -16.3   500    660     255     -1.3    IBm V-VI     M31?
And XXV                119.2  -15.9   -9.7   642    736      90     -1.8    dSph         M31 
And III      KK 5      119.37 -26.26 -10.2   360    723      86     -1.7    dSph         M31 
NGC 147      DDO 3     119.82 -14.25 -15.1   503    712     118     -1.1    dE5          M31 
And XVII               120.23 -18.47  -8.5   262    727      67     -1.9    dSph         M31 
And XXVII              120.4  -17.4   -7.9   657   1255     482     -1.7    dSph         M31 
Cas II       And XXX   120.46 -13.15  -8.0   267    681     145     -1.7    dSph         M31 
Cas III      And XXXII 120.5  -11.2  -12.3  1456    772     144             dSph         M31 
M110         NGC 205   120.72 -21.14 -16.4   673    824      60     -0.5    dE5/p        M31 
NGC 185                120.79 -14.48 -15.2   266    620     181     -0.8    dE3          M31 
And VIII     M31 part  121.02 -22.22                830       -             dSph pec:    M31 
And IV                 121.11 -22.27 -12.6         6300       -             dIrr:        ??  
M32          NGC 221   121.15 -21.98 -16.5   220    770       6     -1.1    cE2          M31 
M31          NGC 224   121.17 -21.57 -21.2  4760    785     300      0.42   SAb II       M31 
And I        KK 8      121.68 -24.82 -11.8   600    727      68     -1.4    dSph/dE3     M31 
And XI                 121.72 -29.06  -6.9   158    763     102     -1.9    UFD          M31 
And XII                122.00 -28.49  -6.4   324    928     181     -2.0    UFD          M31 
And XIV                122.97 -33.17  -8.3   413    793     161     -2.2    dSph         M31 
And XIII               123.03 -29.87  -6.7   172    760     115     -2.0    UFD          M31 
And IX                 123.21 -19.68  -8.1   530    600     182     -2.2    dSph         M31 
And XVI                124.91 -30.46  -9.2   170    476     319     -1.7    dSph         M31 
And X                  125.75 -17.98  -8.1   340    670     130     -2.0    dSph         M31 
And V                  126.22 -15.12 -10.2   302    742     113     -1.9    dSph         M31 
LGS 3        Psc I     126.76 -40.89 -10.4          769     285     -2.1    dIrr/dSph    M31?
And XXIV               127.8  -16.3   -7.6   548    898     169     -1.8    dSph         M31 
And XV                 127.88 -24.53  -9.4   270    626     174     -1.1    dSph         M31 
And II       KK 12     128.92 -29.16 -11.8  1230    630     195     -1.5    dSph         M31 
IC 1613      DDO 8     129.74 -60.58 -15.3  1440    715     505     -1.3    IBm V-VI     M31?
And XXIII              131.0  -23.6  -10.2  1001    748     127     -1.8    dSph         M31 
And XXII     (Tri I)   132.6  -34.1   -6.5   252    920     275     -1.8    UFD          M31 
M33          NGC 598   133.61 -31.33 -18.9  3320    820     210     -0.3    SAcd III-IV  M31?
UGCA 86                139.76  10.65 -17.7          525    3770             Im V-VI:     LG??
UGCA 92                144.71  10.52 -14.5          640                     Im V-VI:     LG??
And XXXIII   Perseus I 147.8  -15.5  0,3     400    785     374             dSph         M31 
UMa II                 152.46  37.44  -4.2   140     32.0    36.5   -2.47   UFD          MW  
UMa I                  159.43  54.41  -5.5   318     97.0   104.9   -2.18   UFD          MW  
UGC 4879     VV 124    164.67  42.88 -11.5         1100    1000     -1.37   IAm          LG??
Leo A        DDO 69    196.90  52.42 -11.5   475    950     980     -2.1    IBm V-VI     LG  
Leo T                  214.85  43.66  -7.1   178    420     425     -1.99   UFD          MW? 
Leo P                  219.65  54.43         290   1750                     dSph         LG? 
Leo II       DDO 93    220.17  67.23 -10.1   151    205     208     -1.62   dSph pec     MW  
Leo I        DDO 74    225.99  49.11 -11.9   246    250     254     -1.43   dSph         MW  
Col I                  231.62 -28.88  -4.5   103    182                     UFD          MW  
Sex B        DDO 70    233.20  43.78 -14.3   715   1630     730     -1.9    IBm V-VI     N310
For I        ESO 356-4 237.10 -65.65 -13.1   668    138     140     -0.99   dSph         MW  
CMa I                  239.99  -8.00  -8.3           13.0     8.0           dIrr         MW  
Sex I                  243.50  42.27  -9.5   682     86      89     -1.93   dSph         MW  
Sex A        DDO 75    246.15  39.88  -9.5   300   1380     530     -1.9    IBm V-VI     N310
Eri II                 249.78 -51.65  -6.6   172    380             -1.5    UFD          MW  
Ant B                  259.41  21.08  -9.7   273   1290      70      -.5    dSph         N310
Car I                  260.11 -22.22  -9.4   241    101     103     -2.0    dSph         MW  
Leo V                  261.86  58.54  -4.3    42    180     180.8           UFD          MW  
NGC 3109     DDO 236   262.10  23.07 -15.8         1285    1720     -1.7    SBm V        N310
Ant A                  263.10  22.31 -10.7         1320      40     -1.9    IABm V-VI    N310
Leo IV                 265.44  56.51  -5.8   116    158     160.6   -2.54   UFD          MW  
Phe I        ESO 245-7 272.16 -68.95  -9.8          445     445     -1.9    IAm V-VI     MW? 
LMC                    280.47 -32.89 -18.5  3000     51.0    50     -0.6    SBm V        MW  
Crater II              282.91  42.03  -8.2  1066    120             -1.7    dSph         MW  
Scl I                  287.54 -83.16  -9.8   260     79      79     -1.68   dSph         MW  
Hydra II               295.61  30.46  -4.8    68    134     128     -2.2    UFD          MW  
SMC          NGC 292   302.80 -44.30 -17.1  1000     60      57     -1.2    SBm V pec    MW  
GR 8         DDO 155   310.74  76.98 -12.5   108    940    2500     -2.0    Im V-VI      LG??
Tuc IV                 313.29 -55.29  -3.5   127     48             -2.3    UFD          MW  
Tuc I                  322.91 -47.37  -9.6   207    875    1110     -1.7    dE4          LG  
Tuc II                 328.08 -52.33  -4.4   199     69                     UFD          MW  
IC 5152      ESO 237-27343.92 -50.19 -15.7          590    1830     -1.4    IAm V-VI     LG??
Grus II                351.15 -51.94  -3.9    93     53             -2.0    UFD          MW  
Boö I                  358.08  69.62  -5.7   242     60.0    57.6   -2.5    UFD          MW  

M:  Absolute visual Magnitude, Rh: Half light radius in pc.
Dh: Heliocentric distance in kpc.
Dnear: Distance to the nearest Subgroup center (MW, M31, NGC 3109) in kpc, for those and LG field galaxies 
    distance to the Local Group barycenter in kpc.

Metal. [Fe/H]: Metallicity = log(NFe/NH)star - log(NFe/NH)sun
    Logarithm of the average abundance of elements heavier than helium and hydrogen (= metals), measured as 
    the spectral ratio of iron to hydrogen relative to the solar ratio.
 
Subgroup: 
    There are three such groups currently recognized in the Local Group:
    MW: The Milky Way and it's satellite galacies 
    M31: Andromeda (including M33) and satellites  
    N3109: The small NGC 3109 group, possible Local Group member
    LG are Local Group galaxies not belonging to any subgroup
    ? means probable, ?? unlikely membership.

Links & References
Old versions of the chart
Milky Way Satellites & The Local Group (SEDS)
Mike Irwin List of Local Group members
PAndAS (The Pan-Andromeda Archaeological Survey)

Metz et al. (2006) The spatial distribution of the Milky Way and Andromeda satellite galaxies arXiv:astro-ph/0610.933v1
Metz et al. (2009) Discs of Satellites: the new dwarf spheroidals arXiv:astro-ph/0901.1658v1

Discovery papers
Milky Way:
Martin et al. (2003) A dwarf galaxy remnant in Canis Major: The fossil of an in-plane accretion onto the Milky Way arXiv:astro-ph/0311.010v1 (CMa dwarf)
Willmann et al. (2005) A New Milky Way Dwarf Galaxy in Ursa Major arXiv:astro-ph/0503.552v2 (UMa I)
Zucker et al. (2006) A New Milky Way Dwarf Satellite in Canes Venatici arXiv:astro-ph/0604.354v1 (CVn I)
Belokurov et al. (2006) Cats and Dogs, Hair and a Hero: A Quintet of New Milky Way Companions arXiv:astro-ph/0608.448v1 (Leo IV, CVn II, Com, Her dSphs & Segue 1)
Zucker et al. (2006) A Curious New Milky Way Satellite in Ursa Major arXiv:astro-ph/0606.633 (UMa II)
Irwin et al. (2007) Discovery of an Unusual Dwarf Galaxy in the Outskirts of the Milky Way arXiv:astro-ph/0701.154v1 (Leo T)
Walsh et al. (2007) A Pair of Boötes - A New Milky Way Satellite arXiv:astro-ph/0705.1378 (Boötes I & II)
Belokurov et al. (2008) Leo V - A Companion of a Companion of the Milky Way Galaxy? arXiv:astro-ph/0807.2831v2 (Leo V)
Belokurov et al. (2010) Big Fish, Small Fish: Two New Ultra-Faint Satellites of the Milky Way. arXiv:astro-ph/1002.0504v1 (Pisces II, Segue 3)
Grillmair, C.J. (2011) Another Look at the EBS: A Stellar Debris Stream and a Possible Progenitor. arXiv:astro-ph/1107.5044v1
Giovanelli et al. (2013) Alfalfa Discovery of the Nearby Gas-Rich Dwarf Galaxy Leo P. arXiv:astro-ph/1305.0272
Sand et al. (2015) Antlia B: A Faint Dwarf Galaxy Member of the NGC 3109 Association. arXiv:astro-ph/1508.01800

Andromeda:
Zucker et al. (2006) Andromeda X, A New Dwarf Spheroidal Satellite of M31: Photometry arXiv:astro-ph/0601.599 (And X)
Martin et al. (2006) Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy. arXiv:astro-ph/0607.472v1 (And XI-XIII)
Majewski et al. (2007) Discovery of Andromeda XIV: A Dwarf Spheroidal Dynamical Rogue in the Local Group? arXiv:astro-ph/0702.635v2 (And XIV)
Ibata et al. (2007) The Haunted Halos of Andromeda and Triangulum: A Panorama of Galaxy Formation in Action. (And XV & XVI)
Irwin et al. (2008) Andromeda XVII: A New Low Lumiosity Satellite of M31. arXiv:astro-ph/0802.0698v1 (And XVII)
McConnachie et al. (2008) A trio of new Local Group galaxies with extreme properties. arXiv:astro-ph/0806.3988v1 (And XVIII-XX)
Collins et al. (2009) A Keck/DEIMOS spectroscopic survey of the faint M31 satellites And IX, AndXI, AndXII and AndXIII. arXiv:astro-ph/0911.1365v1
Martin et al. (2009) PAndAs' Cubs: discovery of two new dwarf galaxies in the surroundings of the Andromeda and Triangulum galaxies. arXiv:astro-ph/0909.0399v3 (And XXI+XXII)
Richardson et al. (2010) PAndAs' Progeny: Extending the M31 Dwarf Galaxy Cabal. arXiv:astro-ph/1102.2902v1 (And XXIII-XXVII)
Conn et al. (2012) A Bayesian Approach to Locating the Red Giant Branch Tip Magnitude (Part Ii): Distances to the Satellites of M31. arXiv:astro-ph/1209.4952
Slater et al. (2011) Andromeda XXVIII: A Dwarf Galaxy More Than 350 kpc from Andromeda arXiv:astro-ph/1110.5903
Bell et al. (2011) Andromeda XXIX: A New Dwarf Spheroidal Galaxy 200 kpc from Andromeda arXiv:astro-ph/1110.5906
Conn et al. (2013) The Three-Dimensional Structure of the M31 Satellite System: Strong Evidence for an Inhomogeneous Distribution of Satellites. arXiv:astro-ph/1301.7131
Martin et al. (2013) Lacerta I and Cassiopeia III: Two Luminous and Distant Andromeda Satellite Dwarf Galaxies Found in the 3? Pan-Starrs1 Survey (And XXXI/XXXII) arXiv:astro-ph/1305.5301