The ALHAMBRA survey: tight dependence of the optical mass-to-light ratio on galaxy colour up to z = 1.5

C. López-Sanjuan, L. A. Díaz-García, A. J. Cenarro, A. Fernández-Soto, K. Viironen, A. Molino, N. Benítez, D. Cristóbal-Hornillos, M. Moles, J. Varela, P. Arnalte-Mur, B. Ascaso, F. J. Castander, M. Cerviño, R. M. González Delgado, C. Husillos, I. Márquez, J. Masegosa, A. Del Olmo, M. Pović, J. Perea

Published 2018-05-09Version 1

Our goal is to characterise the dependence of the optical mass-to-light ratio on galaxy colour up to z = 1.5, expanding the redshift range explored in previous work. From the ALHAMBRA redshifts, stellar masses, and rest-frame luminosities provided by the MUFFIT code, we derive the mass-to-light ratio vs. colour relation (MLCR) both for quiescent and star-forming galaxies. The intrinsic relation and its physical dispersion are derived with a Bayesian inference model. The rest-frame i-band mass-to-light ratio of quiescent and star-forming galaxies presents a tight correlation with the rest-frame (g - i) colour up to z = 1.5. Such MLCR is linear for quiescent galaxies and quadratic for star-forming galaxies. The intrinsic dispersion in these relations is 0.02 dex for quiescent galaxies and 0.06 dex for star-forming ones. The derived MLCRs do not present a significant redshift evolution and are compatible with previous local results in the literature. Finally, these tight relations also hold for g- and r-band luminosities. The derived MLCRs in ALHAMBRA can be used to predict the mass-to-light ratio from a rest-frame optical colour up to z = 1.5. These tight correlations do not change with redshift, suggesting that galaxies have evolved along the derived relations during the last 9 Gyr.