Observations at different wavelengths→ complementary informationM31 Caltech – ROSAT – Chandra – GALEX – IRASObservations at different wavelengths→ complementary informationGALEX – SDSS(Gil de Paz+06)UV opt.U. Fritze, HD Grad. Days 2008U. Fritze, HD Grad. Days 2008Observations at different wavelengths➜ complementary informationGALEX M51(Johnson+06)Local GalaxiesNormal (= big) galaxies : Hubble sequenceE, S0, Sa, Sb, , Sc, Sd, Irr(E. Hubble 1923ff)GALEX – optical – SpitzerUV mid-IRFUV : blue 6“ 6 resol.Hα : green degraded to 6“ 624 µm m dust : red 6“ 6 resol.U. Fritze, HD Grad. Days 2008M 87M 32M 31LMCNGC 205Dwarf galaxies : dE, dSph, dILow surface brightness galaxies : E, disk, dwarfStarburst galaxies, interacting galaxies, radio gals,AGN, ULIRGs, , SCUBA gals, Lyman Break Gals, . . .U. Fritze, HD Grad. Days 2008Local GalaxiesNormal (= big) galaxies : EllipticalsM 87Local GalaxiesNormal (= big) galaxies : EllipticalsM 87~ spheroidal e:= 1-b/a, 0 ≤ e ≤ 0.7stellar densities : not measurable➜ surface brightnessde Vaucouleurs r ¼ -surfacebrightness profileR e:= effective radius= half light radiusI e:= intensity within R eU. Fritze, HD Grad. Days 2008disky – boxy Eslow-L – high-Lold, low-mass starsK-star type spectrum, red coloursno HI, no molecular gas, no SFwide range in luminosities : -25 ≤ M B[mag] ≤ -12cD . . . . . . . . . . . dEM - M = V V -2.5 log F V/FV [mag]10 ≤ M/L ≤ 100 (in solar units [M /L ])U. Fritze, HD Grad. Days 20086