Galaxy populations in groups and clusters-II. Conditional luminosity functions at redshifts from z~1 to z~0

Abstract

Using DESI SV3 spectroscopic group centrals and HSC photometric data, we measure conditional luminosity functions (CLFs) of central and satellite galaxies for red and blue populations in dark matter haloes spanning $M_h\sim 10^{12}-10^{15}{M}_{\odot }$ and $0<z<1$. HSC depth permits measurements to $M_r\approx -15$ at $0.2⩽z<0.5$ and $M_r\approx -17$ at $0.5⩽z<1.0$. We find satellite CLFs evolve weakly over $0<z<1$. Blue satellite CLFs are well described by a single Schechter function across halo masses and redshifts, with a nearly constant slope of $-1.25\lesssim \alpha \lesssim -1.2$. In contrast, red satellite CLFs exhibit a pronounced faint-end upturn in all halo mass and redshift bins, with little evolution in the faint-end slope ($-1.8\lesssim {\alpha }_f\lesssim -1.7$). The low-mass red sequence was therefore already established in clusters/groups by $z\sim 1$. The lack of faint-end-slope evolution favors models where the steep upturn originates from early formation processes at $z\gtrsim 2$, rather than environmental quenching after infall. Satellite characteristic magnitudes and central galaxy luminosities fade with time. Red central galaxies are consistent with passive evolution, whereas blue-central luminosity evolution is dominated by ongoing star formation. Satellites evolve more rapidly than predicted by simple stellar population models, highlighting environmental effects. Satellite quenched fractions as a function of stellar mass exhibit a minimum at $M_{\ast }\sim 10^9{M}_{\odot }$ that is consistent across halo masses and redshifts. We discuss possible interpretations of these results and their implications for galaxy formation and evolution.

16 pages main text + 15 pages appendix, 18 figures in total (8 in the main text and 10 in the appendix). Accepted for publication in MNRAS