Galaxies

64 158 CATALOGUED

Gravitationally bound systems of stars, gas and dark matter — the structures the universe organises itself into.

RANKED LISTS

Andromeda Galaxy — 2.537 Mly away

Large Magellanic Cloud — apparent magnitude 0.29 (V)

PRIMER — 60 SECONDS

Reading the Hubble type

E is elliptical, S is spiral, SB is barred spiral, Irr is irregular. The trailing letter grades how tightly the arms wind: Sa is tight, Sc is open.

Why distances are uncertain

Beyond the local group, distance is inferred from redshift, which needs an expansion rate to convert. That rate is measured two ways that disagree — Planck's 67.4 km/s/Mpc and SH0ES's 73.04 — so every redshift distance here carries ±4% that no telescope can remove until that argument ends. This catalogue divides by the round number between them, H0 = 70, and it does the dividing itself for every galaxy: the redshifts come from several surveys, and where one published distances under an expansion rate of its own, the conversion was re-run rather than the number copied, so that two galaxies in one cluster are not 3.5% apart for a reason that has nothing to do with either. The error bar beside the number carries that ±4%, and adds the galaxy's own motion through space to it.

Photometric and spectroscopic redshifts

A spectroscopic redshift is measured: the lines in the spectrum are where they are, and the number is good to a few per cent. A photometric redshift is fitted — the galaxy's colours through a handful of filters, matched against templates — and GLADE+, which supplies most of the galaxies here, gives it a standard deviation of 20% of itself. The distance says which one it came from, and the error bar beside a photometric one is several times wider than a spectroscopic neighbour's for that reason and not because the galaxy is further away.

[

THE FAMOUS ONES

] 12 ENTRIES

NAME

CLASS

MASS

DISTANCE

MAG

CONSTELLATION

Andromeda Galaxy★

Spiral galaxy Sb

Triangulum Galaxy★

Spiral galaxy Sc

Bode's Galaxy★

Spiral galaxy Sab

Lenticular galaxy S0

Intermediate spiral galaxy SABc

Elliptical galaxy E

Cigar Galaxy★

Spiral galaxy S?

Whirlpool Galaxy★

Intermediate spiral galaxy SABb

Black Eye Galaxy★

Intermediate spiral galaxy SABa

Sombrero Galaxy★

Spiral galaxy Sa

Sunflower Galaxy★

Spiral galaxy Sbc

Virgo Galaxy★

Elliptical galaxy E

ALL CLASSES GALAXY · 32 780 SPIRAL GALAXY · 5608 SPIRAL GALAXY SC · 2529 ELLIPTICAL GALAXY E · 2250 SPIRAL GALAXY SBC · 1601 LENTICULAR GALAXY S0 · 1422 LENTICULAR GALAXY · 1420 SPIRAL GALAXY SB · 1239 LENTICULAR GALAXY S0-A · 1008 SPIRAL GALAXY S · 871 IRREGULAR GALAXY DI · 762 SPIRAL GALAXY SAB · 708

BY CONSTELLATION · 87 REGIONS

VIRGO · 5249 LEO · 3582 URSA MAJOR · 3095 CETUS · 3007 HYDRA · 2780 CENTAURUS · 2429 BOÖTES · 2270 COMA BERENICES · 2174 PISCES · 1905 ERIDANUS · 1884 CANES VENATICI · 1629 PEGASUS · 1545 SCULPTOR · 1498 FORNAX · 1308 CANCER · 1280 HERCULES · 1254 LYNX · 1102 AQUARIUS · 1092 DRACO · 1036 ANDROMEDA · 988 SEXTANS · 978 PISCIS AUSTRINUS · 925 PHOENIX · 918 PERSEUS · 827 LEO MINOR · 793 PAVO · 758 SAGITTARIUS · 716 SERPENS · 638 ARIES · 630 CAMELOPARDALIS · 584 GRUS · 582 GEMINI · 579 INDUS · 577 TELESCOPIUM · 548 CRATER · 538 LIBRA · 537 LEPUS · 510 ANTLIA · 509 TAURUS · 466 PUPPIS · 451 CAPRICORNUS · 447 MICROSCOPIUM · 421 CARINA · 402 CORVUS · 397 VELA · 386 COLUMBA · 380 TRIANGULUM · 374 TRIANGULUM AUSTRALE · 360 CANIS MAJOR · 341 HOROLOGIUM · 335 LUPUS · 328 ORION · 327 TUCANA · 323 OPHIUCHUS · 313 PICTOR · 290 DORADO · 268 AURIGA · 252 CORONA BOREALIS · 244 OCTANS · 227 VOLANS · 219 PYXIS · 212 AQUILA · 200 HYDRUS · 199 RETICULUM · 198 LACERTA · 195 CAELUM · 185 URSA MINOR · 181 LYRA · 164 ARA · 162 CYGNUS · 162 APUS · 152 CEPHEUS · 131 CASSIOPEIA · 130 DELPHINUS · 129 SCORPIUS · 127 CORONA AUSTRALIS · 125 MENSA · 119 CANIS MINOR · 111 NORMA · 93 CHAMAELEON · 83 MONOCEROS · 78 EQUULEUS · 71 MUSCA · 71 VULPECULA · 37 CIRCINUS · 13 CRUX · 13 SAGITTA · 12