Galaxy populations within clusters in the 2PIGG catalogue V. Eke (University of Durham) The 2PIGG catalogue Integrated properties (M/L & stellar masses) Galaxy properties (L.F., profiles in r and v) Central galaxies

Calculating the group mass Dynamically-inferred masses using group velocity dispersions and projected sizes. (The 5 is chosen to match DM FOF b=0.2 haloes.)

Calculating the group luminosity, Lb Correct for galaxies beneath the flux limit assuming a universal Schechter function, M*=-19.72, a=-1.18 (cf Norberg et al 2002).

Galaxy populations within clusters in the 2PIGG catalogue Integrated properties (M/L & stellar masses) Galaxy properties (L.F., profiles in r and v) Central galaxies

Measuring stellar masses b- and r-band fluxes from SuperCOSMOS. Some J- and K-band fluxes from 2MASS. Fluxes+redshifts => luminosities. Kennicutt stellar IMF + Bruzual & Charlot stellar evolution. Model galaxy tracks with exponential SF timescales, metallicity=0.005 and a 5% burst at one of a set of times to fit galaxy colours. See Eke et al., 2005, MNRAS, 362, 1233 for details.

Integrated cluster properties

Galaxy populations within clusters in the 2PIGG catalogue Integrated properties (M/L & stellar masses) Galaxy properties (L.F., profiles in r and v) Central galaxies

Galaxy luminosity functions within groups

Galaxy positions within clusters Stack together clusters with at least 20 members, using dynamically-inferred masses. 1) The projected galaxy number density profile (see also Collister & Lahav, 2005, MNRAS,361,415) 2) The line-of-sight velocity distribution

Projected galaxy number density profiles

Galaxy populations within clusters in the 2PIGG catalogue Integrated properties (M/L & stellar masses) Galaxy properties (L.F., profiles in r and v) Central galaxies

cf. Yang etal, 2005, MNRAS,358,217

Conclusions 1) The largest 2PIGGs have a Schechter function + central galaxy LF 2) Redder galaxies are less conc. in angular position, but more conc. in velocity 3) Central galaxy contains ~4% of cluster stellar mass 4) Redder central galaxies tend to have slightly redder satellites in their haloes at fixed mass