Stellar populations of galaxies in the ALHAMBRA survey up to z  ∼  1

III. The stellar content of the quiescent galaxy population during the last 8 Gyr^⋆

¹ Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, Floor 2, 44001 Teruel, Spain
e-mail: ladiaz@asiaa.sinica.edu.tw
² Academia Sinica Institute of Astronomy & Astrophysics (ASIAA), 11F of Astronomy-Mathematics Building, AS/NTU, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan
³ Centro de Estudios de Física del Cosmos de Aragón (CEFCA) – Unidad Asociada al CSIC, Plaza San Juan 1, Floor 2, 44001 Teruel, Spain
⁴ Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
⁵ Instituto de Física de Cantabria (CSIC-UC), 39005 Santander, Spain
⁶ Unidad Asociada Observatorio Astronómico (IFCA-UV), 46980 Paterna, Spain
⁷ IAA-CSIC, Glorieta de la Astronomía s/n, 18008 Granada, Spain
⁸ Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain
⁹ Observatório Nacional-MCT, Rua José Cristino, 77, 20921-400 Rio de Janeiro, RJ, Brazil
¹⁰ Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080 Bilbao, Spain
¹¹ Ikerbasque, Basque Foundation for Science, Bilbao, Spain
¹² Departamento de Física Atómica, Molecular y Nuclear, Facultad de Física, Universidad de Sevilla, 41012 Sevilla, Spain
¹³ Institut de Ciències de l’Espai (IEEC-CSIC), Facultat de Ciències, Campus UAB, 08193 Bellaterra, Spain
¹⁴ Departamento de Astrofísica, Facultad de Física, Universidad de La Laguna, 38206 La Laguna, Spain
¹⁵ Instituto de Astrofísica, Universidad Católica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile
¹⁶ Centro de Astro-Ingeniería, Universidad Católica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago, Chile
¹⁷ Observatori Astronòmic, Universitat de València, C/ Catedràtic José Beltrán 2, 46980 Paterna, Spain
¹⁸ Departament d’Astronomia i Astrofísica, Universitat de València, 46100 Burjassot, Spain
¹⁹ Instituto de Astronomía, Geofísica e Ciéncias Atmosféricas, Universidade de São Paulo, São Paulo, Brazil

Received: 22 February 2018
Accepted: 7 June 2019

Abstract

Aims. We aim at constraining the stellar population properties of quiescent galaxies. These properties reveal how these galaxies evolved and assembled since z ∼ 1 up to the present time.

Methods. Combining the ALHAMBRA multi-filter photo-spectra with the fitting code for spectral energy distribution MUFFIT (MUlti-Filter FITting), we built a complete catalogue of quiescent galaxies via the dust-corrected stellar mass vs. colour diagram. This catalogue includes stellar population properties, such as age, metallicity, extinction, stellar mass, and photometric redshift, retrieved from the analysis of composited populations based on two independent sets of simple stellar population (SSP) models. We developed and applied a novel methodology to provide, for the first time, the analytic probability distribution functions (PDFs) of mass-weighted age, metallicity, and extinction of quiescent galaxies as a function of redshift and stellar mass. We adopted different star formation histories to discard potential systematics in the analysis.

Results. The number density of quiescent galaxies is found to increase since z ∼ 1, with a more substantial variation at lower stellar mass. Quiescent galaxies feature extinction A_V <  0.6, with median values in the range A_V = 0.15–0.3. At increasing stellar mass, quiescent galaxies are older and more metal rich since z ∼ 1. A detailed analysis of the PDFs reveals that the evolution of quiescent galaxies is not compatible with passive evolution and a slight decrease of 0.1–0.2 dex is hinted at median metallicity. The intrinsic dispersion of the age and metallicity PDFs show a dependence on stellar mass and/or redshift. These results are consistent with both sets of SSP models and assumptions of alternative star formation histories explored. Consequently, the quiescent population must undergo an evolutive pathway including mergers and/or remnants of star formation to reconcile the observed trends, where the “progenitor” bias should also be taken into account.