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تسجيل مستخدم جديدStellar populations of galaxies in the ALHAMBRA survey up to $z sim 1$. IV. Properties of quiescent galaxies on the stellar mass$-$size plane
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We perform a comprehensive study of the stellar population properties of quiescent galaxies as a function of size and stellar mass to constrain the physical mechanism governing the stellar mass assembly and the likely evolutive scenarios that explain their growth in size. After selecting all the quiescent galaxies from the ALHAMBRA survey by the dust-corrected stellar mass$-$colour diagram, we built a shared sample of $sim850$ quiescent galaxies with reliable sizes from the HST. The stellar population properties were retrieved using the SED-fitting code MUFFIT with various sets of composite stellar population models. Age, formation epoch, metallicity, and extinction were studied on the stellar mass$-$size plane as function of size through a Monte Carlo approach. This accounted for uncertainties and degeneracy effects amongst stellar population properties. The stellar population properties of quiescent galaxies and their stellar mass and size since $zsim1$ are correlated. At fixed stellar mass, the more compact the quiescent galaxy, the older and richer in metals it is ($1$Gyr and $0.1$dex, respectively). In addition, more compact galaxies may present slight lower extinctions than their more extended counterparts at the same stellar mass ($<0.1$ mag). By means of studying constant regions of stellar population properties across the stellar mass$-$size plane, we obtained empirical relations to constrain the physical mechanism that governs the stellar mass assembly of the form $M_star propto r_mathrm{c}^alpha$, where $alpha$ amounts to $0.50-0.55 pm 0.09$. There are indications that support the idea that the velocity dispersion is tightly correlated with the stellar content of galaxies. The mechanisms driving the evolution of stellar populations can therefore be partly linked to the dynamical properties of galaxies, along with their gravitational potential.
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Our aim is to determine the distribution of stellar population parameters (extinction, age, metallicity, and star formation rate) of quiescent galaxies within the rest-frame stellar mass$-$colour and $UVJ$ colour$-$colour diagrams corrected for extin
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We aim at constraining the stellar population properties of quiescent galaxies. These properties reveal how these galaxies evolved and assembled since $zsim1$ up to the present time. Combining the ALHAMBRA multi-filter photo-spectra with the SED-fitt
ing code MUFFIT, we build 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 SSP models. We develop and apply 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 adopt different star formation histories to discard potential systematics in the analysis. The number density of quiescent galaxies is found to increase since $zsim1$, with a more substantial variation at lower mass. Quiescent galaxies feature extinction $A_V<0.6$, with median values in the range $A_V = 0.15mathrm{-}0.3$. At increasing stellar mass, quiescent galaxies are older and more metal rich since $zsim1$. A detailed analysis of the PDFs reveals that the evolution of quiescent galaxies is not compatible with passive evolution and a slight decrease is hinted at median metallicity $0.1mathrm{-}0.2$~dex. The intrinsic dispersion of the age and metallicity PDFs show a dependence with stellar mass and/or redshift. These results are consistent with both sets of SSP models and the alternative SFH assumptions 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.
We present MUFFIT, a new generic code optimized to retrieve the main stellar population parameters of galaxies in photometric multi-filter surveys, and we check its reliability and feasibility with real galaxy data from the ALHAMBRA survey. Making us
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