Suchergebnisse

Aims. We aim at constraining the stellar population properties of quiescent galaxies. These properties reveal how these galaxies evolved and assembled since z similar to 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 similar to 1, with a more substantial variation at lower stellar mass. Quiescent galaxies feature extinction AV progenitor> bias should also be taken into account. © ESO 2019 ; This work has been partly supported by the Programa Nacional de Astronomia y Astrofisica of the Spanish Ministry of Economy and Competitiveness (MINECO, grants AYA2012-30789 and AYA2015-66211-C2-1-P), by the Ministry of Science and Technology of Taiwan (grant MOST 106-2628-M-001-003-MY3), by the Academia Sinica (grant AS-IA-107-M01), and by the Government of Aragon (Research Group E103). L.A.D.G. also thanks the support of I.F. for o ffering the opportunity to develop part of this research at the Mullard Space Science Laboratory (MSSL). We also acknowledge support from the Spanish Ministry for Economy and Competitiveness and FEDER funds through grants AYA201015081, AYA2010-15169, AYA2010-22111-C03-01, AYA2010-22111-C03-02, AYA2011-29517-C03-01, AYA2012-39620, AYA2013-40611-P, AYA201342227-P, AYA2013-43188-P, AYA2013-48623-C2-1, AYA2013-48623-C2-2, ESP2013-48274, AYA2014-57490-P, AYA2014-58861-C3-1, AYA2016-76682-C3-1-P, AYA2016-77846-P, AYA2016-81065-C2-1, AYA2016-81065-C2-2, Generalitat Valenciana projects Prometeo 2009/064, and PROMETEOII/2014/060, Junta de Andalucia grants TIC114, JA2828, P10-FQM-6444, and Generalitat de Catalunya project SGR-1398. The authors acknowledge Y. Peng and A. Citro for sharing their stellar population numerical results. Throughout this research, we made use of the Matplotlib package (Hunter 2007), a 2D graphics package used for Python that is designed for interactive scripting and quality image generation. This paper is dedicated to Marian Leon Canalejo for being there when L.A.D.G. needed her most and for her patience and continuous encouragement while finishing his Ph.D.

Aims. Our aim is to determine the distribution of stellar population parameters (extinction, age, metallicity, and star formation rates) of quiescent galaxies within the rest-frame stellar mass-colour diagrams and UVJ colour-colour diagrams corrected for extinction up to z similar to 1. These novel diagrams reduce the contamination in samples of quiescent galaxies owing to dust-reddened galaxies, and they provide useful constraints on stellar population parameters only using rest-frame colours and /or stellar mass. Methods. We set constraints on the stellar population parameters of quiescent galaxies combining the ALHAMBRA multi-filter photo-spectra with our fitting code for spectral energy distribution, MUlti-Filter FITting (MUFFIT), making use of composite stellar population models based on two independent sets of simple stellar population (SSP) models. The extinction obtained by MUFFIT allowed us to remove dusty star-forming (DSF) galaxies from the sample of red UVJ galaxies. The distributions of stellar population parameters across these rest-frame diagrams are revealed after the dust correction and are fitted by LOESS, a bi-dimensional and locally weighted regression method, to reduce uncertainty effects. Results. Quiescent galaxy samples defined via classical UVJ diagrams are typically contaminated by a similar to 20% fraction of DSF galaxies. A significant part of the galaxies in the green valley are actually obscured star-forming galaxies (similar to 30-65%). Consequently, the transition of galaxies from the blue cloud to the red sequence, and hence the related mechanisms for quenching, seems to be much more efficient and faster than previously reported. The rest-frame stellar mass-colour and UVJ colour-colour diagrams are useful for constraining the age, metallicity, extinction, and star formation rate of quiescent galaxies by only their redshift, rest-frame colours, and /or stellar mass. Dust correction plays an important role in understanding how quiescent galaxies are distributed in these diagrams and is key to performing a pure selection of quiescent galaxies via intrinsic colours.© ESO 2019 ; The authors are grateful to the referee for their fruitful comments, which contributed to improving the present research. This work has been supported by the Programa Nacional de Astronomia y Astrofisica of the Spanish Ministry of Economy and Competitiveness (MINECO, grants AYA2012-30789 and AYA2015-66211-C2-1-P), by the Ministry of Science and Technology of Taiwan (grant MOST 106-2628-M-001-003-MY3), by the Academia Sinica (grant AS-IA-107-M01), and by the Government of Aragon (Research Group E103). L. A. D. G. acknowledges support from the Caja Rural de Teruel. L. A. D. G. also thanks I. F. for offering the opportunity to develop part of this research at the Mullard Space Science Laboratory (MSSL). We also acknowledge support from the Spanish Ministry for Economy and Competitiveness and FEDER funds through grants AYA2010-15081, AYA2010-15169, AYA2010-22111-C03-01, AYA2010-22111-C03-02, AYA2011-29517-C03-01, AYA2012-39620, AYA2013-40611-P, AYA2013-42227-P, AYA2013-43188-P, AYA2013-48623-C2-1, AYA2013-48623-C2-2, ESP2013-48274, AYA201457490-P, AYA2014-58861-C3-1, AYA2016-76682-C3-1-P, AYA2016-77846-P, AYA2016-81065-C2-1, AYA2016-81065-C2-2; Generalitat Valenciana projects Prometeo 2009/064 and PROMETEOII/2014/060; Junta de Andalucia grants TIC114, JA2828, P10-FQM-6444; and Generalitat de Catalunya project SGR-1398. Throughout this research, we made use of the Matplotlib package (Hunter 2007), a 2D graphics package used for Python that is designed for interactive scripting and quality image generation. This paper is dedicated to Marian Leon Canalejo for being there when L. A. D. G. needed her most and for her patience and continuous encouragement he was finishing his PhD.

Reproduced with permission from Astronomy & Astrophysics ; We present a technique that permits the analysis of stellar population gradients in a relatively low-cost way compared to integral field unit (IFU) surveys. We developed a technique to analyze unresolved stellar populations of spatially resolved galaxies based on photometric multi-filter surveys. This technique allows the analysis of vastly larger samples and out to larger galactic radii. We derived spatially resolved stellar population properties and radial gradients by applying a centroidal Voronoi tessellation and performing a multicolor photometry spectral energy distribution fitting. This technique has been successfully applied to a sample of 29 massive (M ∗ > 10 10.5 M ⊙ ) early-type galaxies at z < 0.3 from the ALHAMBRA survey. We produced detailed 2D maps of stellar population properties (age, metallicity, and extinction), which allow us to identify galactic features. Radial structures were studied, and luminosity-weighted and mass-weighted gradients were derived out to 2-3.5 R eff . We find that the spatially resolved stellar population mass, age, and metallicity are well represented by their integrated values. We find the gradients of early-type galaxies to be on average flat in age (⇠log Age L = 0.02 ± 0.06 dex/R eff ) and negative in metallicity (⇠[Fe/H] L = -0.09 ± 0.06 dex/R eff ). Overall,the extinction gradients are flat (⇠A v = -0.03 ± 0.09 mag/R eff ) with a wide spread. These results are in agreement with previous studies that used standard long-slit spectroscopy, and with the most recent IFU studies. According to recent simulations, these results are consistent with a scenario where early-type galaxies were formed through major mergers and where their final gradients are driven by the older ages and higher metallicity of the accreted systems. We demonstrate the scientific potential of multi-filter photometry to explore the spatially resolved stellar populations of local galaxies and confirm previous spectroscopic trends from a complementary technique ; This work has been mainly funded by the FITE (Fondos de Inversiones de Teruel) and the Spanish Ministry for Economy and Competitiveness and FEDER funds through grants AYA2012-30789 and AYA2015-66211-C2-1-P. We also acknowledge financial support from the projects AYA2014-57490-P and AYA2016-77846-P, and from the Aragón Government through the Research Group E103. B.A. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 656354. M.P. acknowledges financial supports from the Ethiopian Space Science and Technology Institute (ESSTI) under the Ethiopian Ministry of Science and Technology (MoST), and from the Spanish Ministry of Economy and Competitiveness (MINECO) through research projects AYA2013-42227-P and AYA2016-76682-C3-1-P (AEI/FEDER, UE).