This is a list of largest galaxies known, sorted by order of increasing major axis diameters. The unit of measurement used is the light-year (approximately 9.46 kilometers).
Overview
Galaxies are vast collections of stars, planets, nebulae and other objects that are surrounded by an interstellar medium and held together by gravity. They do not have a definite boundary by nature, and are characterized with gradually decreasing stellar density as a function of increasing distance from its center. Because of this, measuring the sizes of galaxies can often be difficult and have a wide range of results depending on the sensitivity of the detection equipment and the methodology being used. Some galaxies emit more strongly in wavelengths outside the visible spectrum, depending on its stellar population, whose stars may emit more strongly in other wavelengths that are beyond the detection range. It is also important to consider the morphology of the galaxy when attempting to measure its size – an issue that has been raised by the Russian astrophysicist B.A. Vorontsov-Vel'Yaminov in 1961, which considers separate determination methods in measuring the sizes of spiral and elliptical galaxies.
For a full context about how the diameters of galaxies are measured, including the estimation methods stated in this list, see section Galaxy#Physical diameters.
List
Listed below are galaxies with diameters greater than 700,000 light-years. This list uses the mean cosmological parameters of the Lambda-CDM model based on results from the 2015 Planck collaboration, where H0 = 67.74 km/s/Mpc, ΩΛ = 0.6911, and Ωm = 0.3089. Due to different techniques, each figure listed on the galaxies has varying degrees of confidence in them. The reference to those sizes plus further additional details can be accessed by clicking the link for the NASA/IPAC Extragalactic Database (NED) on the right-hand side of the table.
+Galaxies with diameters greater than 700,000 light-years Galaxy name/designationImage Major axis diameter (in light-years) Minor axis diameter (in light years) Morphology Estimationmethod Link for objectLEDA 2222102 BrClG2MASS K-band total mag ESO 383-76 (ESO 383-G 076) cD5; E5; BrClG 90% total B-light Abell 3112 BCG (ESO 248-6,ESO 248-G 006) S0?; BrClG 90% total B-light IC 1101 ~ cD; S0− ~30 B-mag arcsec−2 ESO 409-25 (ESO 409-G 025) cD4; E4; BrClG 90% total B-light ESO 256-11 SA0^0(s)?90% total B-lightNED Abell 3039 BCG B cD 2MASS K-band total mag ESO 347-9 (ESO 347-G 009) S...; cD 90% total B-light OGC 768 BrClG2MASS K-band total mag 2MASX J14102504+6337103 ~ 2MASS K-band total mag ESO 151-41 (ESO 151-G 041) Sc 90% total B-light ESO 539-13 NED03 (ESO 539-G 013 NED03) E 27.0 B-mag arcsec−2 2MASX J11232449+1511041 ~2MASS K-band total mag Abell 1576 BCG cD db 2MASS K-band total mag 2MASX J11520489+3700324 ~BrClG2MASS K-band total mag ESO 306-17 (ESO 306-G 017) cD3; E3 90% total B-light B2 0247+29 ~~2MASS K-band total mag ESO 350-15 (ESO 350-G 015) cD3; E3 90% total B-light 2MASX J08510173+1638570 ~ BrClG2MASS K-band total mag OGC 94 BrClG 2MASS K-band total mag Abell 2397 BCG cD 2MASS K-band total mag Abell 1146 BCG E 2MASS K-band total mag Abell 747 BCG BrClG 2MASS K-band total mag LEDA 1273002 BrClG 2MASS K-band total mag 6C B084407.8+582055 ~BrCIG2MASS K-band total mag LEDA 1838034 BrClG 2MASS K-band total mag LEDA 1453633 ~BrClG2MASS K-band total mag LEDA 1987660 ~BrClG2MASS K-band total mag ESO 473-5 (ESO 473-G 005) Sc; BrClG 90% total B-light LEDA 2011796 ~~2MASS K-band total mag Abell 1942 BCG BrClG; AGN 2MASS K-band total mag 2MASX J12114313+0801071 ~ 2MASS K-band total mag MCG +09-25-047 ~ Intermediate surface brightness 2MASX J00031162-0605305 ~~2MASS K-band total mag LEDA 1654342 BrClG 2MASS K-band total mag ESO 156-18 (ESO 156-G 018) SAB(s)00: pec 90% total B-light OGC 169 BrClG 2MASS K-band total mag Abell 384 BCG ~ 2MASS K-band total mag ESO 206-2 (ESO 206-G 002) cD; S 90% total B-light ESO 286-41 (ESO 286-G 041) SA(s)0+; cD 90% total B-light 2MASX J10085922+1937154 ~~2MASS K-band total mag Abell 697 BCG BrClG 2MASS K-band total mag OGC 511 BrClG 2MASS K-band total mag Abell 3300 BCG cD 2MASS K-band total mag OGC 666 BrClG 2MASS K-band total mag OGC 233 ~BrClG2MASS K-band total mag 2MASX J11140115+0458199 ~BrClG2MASS K-band total mag SDSS J122944.80+133454.2 ~~0.5-7 keV Chandra OGC 815 ~E;BrClG2-7 keV Chandra WHL J230800.9-015541 BCG ~~2MASS K-band total mag Abell 1437B BCG BrClG 2MASS K-band total mag OGC 116 BrClG 2MASS K-band total mag ESO 443-11 (ESO 443-G 011) cD; SAB00 pec; BrClG 27.0 B-mag arcsec−2 QSO J0931+3204 ~ 2MASS K-band total mag 4C +41.26 BrClG 2MASS K-band total mag LEDA 1633166~~2MASS K-Band total mag GMBCG J135.39754+20.87035 BCG ~BrClG2MASS K-Band total mag 2MASX J16064384+2329162 ~BrClG2MASS K-Band total mag OGC 193 ~BrCIG2MASS K-band total mag 2MASX J20511108+0056456 ~BrClG2MASS K-band total mag LEDA 1239494 ~~2MASS K-band total mag Abell 963 BCG BrClG 2MASS K-band total mag ESO 541-13 (ESO 541-G 013) cD; E3 pec 90% total B-light 4C 18.68 ~ Sy1 2MASS K-band total mag WHL J082728.3+081742 BCG BrClGr SDSS Isophotal OGC 605 ~BrClG2MASS K-band total mag OGC 378 ~BrClG2MASS K-band total mag OGC 560 BrClG 2MASS K-band total mag MACS J0024.5+3312 BCG ~ 2MASS K-band total mag 2MASX J14582288+3613501 ~ BrClG 2MASS K-band total mag 2MASX J09503021+5735027 ~~2MASS K-band total mag OGC 369 BrClG 2MASS K-band total mag Abell 1602 BCG BrClG 2MASS K-band total mag B3 1448+445 BrClG 2MASS K-band total mag 2MASX J08154445+4506521 ~BrClG2MASS K-band total mag 2MASX J02072650+2253472 ~~2MASS K-band total mag 2MASX J11223608+2235295 ~BrClG2MASS K-band total mag LEDA 1662572 ~~2MASS K-band total mag NGC 623 cD; E 27.0 B-mag arcsec−2 PGC 6616 E 27.0 B-mag arcsec−2 Abell 1413 BCG cD; E; BrClG 25.0 r-mag arcsec−2 LEDA 1143180 ~ 2MASS K-band total mag Abell 773N BCG BrClG; cD 2MASS K-band total mag ESO 291-9 (ESO 291-G 009) cD4; SA0−;BrClG 90% total B-light LEDA 1678798 ~ BrClG 2MASS K-band total mag Abell 1504 BCG BrClG 2MASS K-band total mag LCSB S1161P BrClG 2MASS K-band total mag OGC 31 ~ 2MASS K-band total mag OGC 763 ~ 2MASS K-band total mag LEDA 1816387 ~ 2MASS K-band total mag LEDA 1118210 BrClG 2MASS K-band total mag NVSS J080730+340042 BrClG 2MASS K-band total mag LEDA 2066332 ~ 2MASS K-band total mag OGC 1311 BrClG 2MASS K-band total mag Abell 812 BCG BrClG 2MASS K-band total mag OGC 856 BrClG 2MASS K-band total mag 7C 1043+5953 BrClG 2MASS K-band total mag Abell 1785B BCG BrClG 2MASS K-band total mag LEDA 2463193 BrClG 2MASS K-band total mag NGC 5084 S0 90% total B-light Abell 781 b BrClG 25.0 r-mag arcsec−2 B2 1132+32 BrClG 2MASS K-band total mag OGC 231 BrClG 2MASS K-band total mag OGC 26 BrClG 2MASS K-band total mag Abell 655 BCG BrClG 2MASS K-band total mag OGC 499 ~ 2MASS K-band total mag LEDA 1460988 BrClG 2MASS K-band total mag 2MASX J01331683+2311233 ~ 2MASS K-band total mag Abell 908 BCG BrClG 2MASS K-band total mag 2MASX J00193870+0335573 ~ 2MASS K-band total mag Abell 2061 b BrClG 2MASS K-band total mag 2MASX J14475695+1445330 ~BrClG2MASS K-band total mag 2MASX J14562781+0438121 ~BrClG2MASS K-band total mag OGC 188 BrClG 2MASS K-band total mag ESO 198-1 (ESO 198-G 001) cD4; E4 27.0 B-mag arcsec−2 GMBCG J198.26268+35.32836 BCG ~BrClG2MASS K-band total mag 3C 295 E/S0;LEG;BrClG NLRG 2MASS K-band total mag OGC 199 BrClG 2MASS K-band total mag Abell 267 BCG BrClG 25.0 r-mag arcsec−2 2MASX J10360840+2614194 ~BrClG2MASS K-band total mag Abell 1758N BCG BrClG 2MASS K-band total mag Abell 360 BCG cD 2MASS K-band total mag ESO 251-21 (ESO 251-G 021) SAB0− pec; E/S0 90% total B-light 2MASX J09573699+0234255 BrClG2MASS K-band total mag OGC 667 BrClG 2MASS K-band total mag LEDA 2188433 BrClG 2MASS K-band total mag OGC 235 BrClG 2MASS K-band total mag Abell 1807 BCG cD 2MASS K-band total mag OGC 898 ~ 2MASS K-band total mag OGC 505 ~BrClG2MASS K-band total mag NGC 6872 SAB(rs)c 25.5 r-mag arcsec−2 Abell S1077 BCG ~ 2MASS K-band total mag Abell 2125 BCG E 2MASS K-band total mag B3 1715+425 BrClG; AGN 2MASS K-band total mag 2MASX J09155189+2504407 ~BrClG2MASS K-band total mag Abell 2219 BCG BrClG 2MASS K-band total mag OGC 966 BrClG 2MASS K-band total mag ESO 552-20 (ESO 552-G 020) cD; E 90% total B-light OGC 512 BrClG 2MASS K-band total mag LEDA 2304600 ~cD2MASS K-band total mag ESO 11-4 (ESO 011-G 004) cD4; E4 pec 90% total B-light 2MASX J10330846+0902144 ~BrClG2MASS K-band total mag IC 1633 cD; E1 27.0 B-mag arcsec−2 ESO 443-4 (ESO 443-G 004) cD; S0; BrClG 90% total B-light LEDA 2262657 BrClG 2MASS K-band total mag LEDA 1869052 BrClG 2MASS K-band total mag NGC 1759 cD; E 27.0 B-mag arcsec−2 LEDA 1869814 BrClG 2MASS K-band total mag 2MFGC 12274 ~ 25.0 B-mag arcsec−2 Abell S235 BCG cD 2MASS K-band total mag
Listed below are some notable galaxies under 700,000 light-years in diameter, for the purpose of comparison. All links to NED are available, except for the Milky Way, which is linked to the relevant paper detailing its size.
+Notable galaxies with diameters 700,000 light-years or less Galaxy name/designationImage Major axis diameter (in light-years) Minor axis diameter (in light years) Morphology Estimationmethod Link for object ESO 444-46 (ESO 444-G 046) cD4; E4; BrClG 27.0 B-mag arcsec−2 NGC 4038 SB(s)m pec 27.0 B-mag arcsec−2 Tadpole Galaxy SB(s)c pec 25.0 B-mag arcsec−2 Abell 2261 BCG cD; E 2MASS K-band total mag Hercules A E; WLRG; NLRG 2MASS K-band total mag UGC 2885 ("Rubin's Galaxy") SA(rs)c 25.0 B-mag arcsec−2 NGC 1399 cD; E1 pec 90% total B-light NeVe 1 cD; E 2MASS K-band total mag Alcyoneus E 25.0 r-mag arcsec−2 Andromeda Galaxy SA(s)b 25.0 mag/arcsec2 Centaurus AS0pec; Sy2; BL Lac 90% total B-light Messier 87 cD; E0–E1 pec; NLRG; Sy 25.0 B-mag arcsec−2 Malin 1 S; LSB 2MASS K-band total mag NGC 262 SA(s)0/a; Sy2 2MASS K-band total mag Messier 81 ("Bode's Galaxy")~SA(s)ab; LINER2MASS K-band total mag Milky Way Sb; Sbc; SB(rs)bc 25.0 B-mag arcsec−2 Messier 82 ("Cigar Galaxy")I0; Sburst2MASS K-band total magLarge Magellanic Cloud~SB(s)m25.0 B-mag arcsec−2
See also List of largest stars List of most massive stars List of most massive black holes List of largest cosmic structures List of largest nebulae List of smallest galaxies
Notes
References
Further reading