2017A&A...599A..62L

Aims. Our goal is to study the evolution of the B-band luminosity function (LF) since z∼1 using ALHAMBRA data.
Methods. We used the photometric redshift and the I-band selection magnitude probability distribution functions (PDFs) of those ALHAMBRA galaxies with I≤24mag to compute the posterior LF. We statistically studied quiescent and star-forming galaxies using the template information encoded in the PDFs. The LF covariance matrix in redshift - magnitude - galaxy type space was computed, including the cosmic variance. That was estimated from the intrinsic dispersion of the LF measurements in the 48 ALHAMBRA sub-fields. The uncertainty due to the photometric redshift prior is also included in our analysis.
Results. We modelled the LF with a redshift-dependent Schechter function affected by the same selection effects than the data. The measured ALHAMBRA LF at 0.2≤z<1 and the evolving Schechter parameters both for quiescent and star-forming galaxies agree with previous results in the literature. The estimated redshift evolution of M_B^*∝Qz is Q_SF=-1.03±0.08 and Q_Q=-0.80±0.08, and of log₁₀φ^*∝Pz is P_SF=-0.01±0.03 and P_Q=-0.41±0.05. The measured faint-end slopes are α_SF=-1.29±0.02 and α_Q=-0.53±0.04. We find a significant population of faint quiescent galaxies with M_B≥-18, modelled by a second Schechter function with slope β=-1.31±0.11.
Conclusions. We present a robust methodology to compute LFs using multi-filter photometric data. The application to ALHAMBRA shows a factor 2.55±0.14 decrease in the luminosity density j_B of star-forming galaxies, and a factor 1.25±0.16 increase in the j_B of quiescent ones since z=1, confirming the continuous build-up of the quiescent population with cosmic time. The contribution of the faint quiescent population to j_B increases from 3% at z=1 to 6% at z=0. The developed methodology will be applied to future multi-filter surveys such as J-PAS.