Star formation along the Hubble sequence Radial structure of the star formation of CALIFA galaxies

González Delgado, Rosa M. et. al.The spatially resolved stellar population content of today's galaxies holds important information for understanding the different processes that contribute to the star formation and mass assembly histories of galaxies. The aim of this paper is to characterize the radial structure of the star formation rate (SFR) in galaxies in the nearby Universe as represented by a uniquely rich and diverse data set drawn from the CALIFA survey. The sample under study contains 416 galaxies observed with integral field spectroscopy, covering a wide range of Hubble types and stellar masses ranging from M* similar to 10(9) to 7 x 10(11) M-circle dot. Spectral synthesis techniques are applied to the datacubes to derive 2D maps and radial profiles of the intensity of the star formation rate in the recent past (Sigma(SFR)), as well as related properties, such as the local specific star formation rate (sSFR), defined as the ratio between Sigma(SFR) and the stellar mass surface density (mu*). To emphasize the behavior of these properties for galaxies that are on and off the main sequence of star formation (MSSF), we stack the individual radial profiles in seven bins of galaxy morphology ( E, S0, Sa, Sb, Sbc, Sc, and Sd), and several stellar masses. Our main results are: ( a) the intensity of the star formation rate shows declining profiles that exhibit very small differences between spirals with values at R = 1 half light radius (HLR) within a factor two of Sigma(SFR) similar to 20 M-circle dot Gyr(-1) pc(-2). The dispersion in the Sigma(SFR)(R) profiles is significantly smaller in late type spirals (Sbc, Sc, Sd). This confirms that the MSSF is a sequence of galaxies with nearly constant Sigma(SFR). (b) sSFR values scale with Hubble type and increase radially outward with a steeper slope in the inner 1 HLR. This behavior suggests that galaxies are quenched inside-out and that this process is faster in the central, bulge-dominated part than in the disks. (c) As a whole and at all radii, E and S0 are off the MSSF with SFR much smaller than spirals of the same mass. (d) Applying the volume corrections for the CALIFA sample, we obtain a density of star formation in the local Universe of rho SFR = (0.0105 +/- 0.0008) M-circle dot yr(-1) Mpc(-3), in agreement with independent estimates. Most of the star formation is occurring in the disks of spirals. (e) The volume-averaged birthrate parameter, which measures the current SFR with respect to its lifetime average, b' = 0.39 +/- 0.03, suggests that the present day Universe is forming stars a about one-third of its past average rate. E, S0, and the bulge of early type spirals (Sa, Sb) contribute little to the recent SFR of the Universe, which is dominated by the disks of Sbc, Sc, and Sd spirals. (f) There is a tight relation between Sigma(SFR) and mu*, defining a local MSSF relation with a logarithmic slope of 0.8, similar to the global MSSF relation between SFR and M*. This suggests that local processes are important in determining the star formation in disks, probably through a density dependence of the SFR law. The scatter in the local MSSF is driven by morphology-related off sets, with Sigma(SFR)/mu* (the local sSFR) increasing from early to late type galaxies, indicating that the shut down of the star formation is more related to global processes, such as the formation of a spheroidal component.Support from the Spanish Ministerio de Economia y Competitividad, through projects AYA2014-57490-P, AYA2010-15081, and Junta de Andalucia FQ1580, AYA2010-22111-C03-03, AYA2010-10904E, AYA2013-42227P, RyC-2011-09461, AYA2013-47742-C4-3-P, EU SELGIFS exchange program FP7-PEOPLE-2013-IRSES-612701, and CONACYT-125180 and DGAPA-IA100815. We also thank the Viabilidad, Diseno, Acceso y Mejora funding program, ICTS-2009-10, for funding the data acquisition of this project.Peer reviewe

CALIFA, the Calar Alto Legacy Integral Field Area survey: IV. Third public data release

This paper describes the third public data release (DR3) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. Science-grade quality data for 667 galaxies are made public, including the 200 galaxies of the second public data release (DR2). Data were obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto Observatory. Three different spectral setups are available: i) a low-resolution V500 setup covering the wavelength range 3745-7500 Å (4240-7140 Å unvignetted) with a spectral resolution of 6.0 Å (FWHM) for 646 galaxies, ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840 Å (3650-4620 Å unvignetted) with a spectral resolution of 2.3 Å (FWHM) for 484 galaxies, and iii) the combination of the cubes from both setups (called COMBO) with a spectral resolution of 6.0 Å and a wavelength range between 3700-7500 Å (3700-7140 Å unvignetted) for 446 galaxies. The Main Sample, selected and observed according to the CALIFA survey strategy covers a redshift range between 0.005 and 0.03, spans the color-magnitude diagram and probes a wide range of stellar masses, ionization conditions, and morphological types. The Extension Sample covers several types of galaxies that are rare in the overall galaxy population and are therefore not numerous or absent in the CALIFA Main Sample. All the cubes in the data release were processed using the latest pipeline, which includes improved versions of the calibration frames and an even further improved image reconstruction quality. In total, the third data release contains 1576 datacubes, including ~1.5 million independent spectra. © 2016 ESO.SFS thanks the CONACYT-125180 and DGAPA-IA100815 projects for providing him support in this study. R.G.B., R.G.D., and E.P. are supported by grants AYA2014-57490-P and JA-FQM-2828. SZ is supported by the EU Marie Curie Integration Grant >SteMaGE> No. PCIG12-GA-2012-326466 (Call Identifier: FP7-PEOPLE-2012 CIG). J. F.-B. from grant AYA2013-48226-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement 289313 B.G-L- acknowledges financial support by the Spanish MINECO under grants AYA2013-41656-P and AYA2015-68217-P Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC12009, awarded to The Millennium Institute of Astrophysics, MAS. L.G. also acknowledges support by CONICYT through FONDECYT grant 3140566, and AYA2013-42227-P from the Spanish Ministerio de Ciencia e Innovacion and TIC 114 and PO08-TIC-3531 from Junta de Andalucia. AG acknowledges support from the FP7/2007-2013 under grant agreement no. 267251 (AstroFIt). RAM was funded by the Spanish programme of International Campus of Excellence Moncloa (CEI). JMA acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). I.M. and A.d.O. acknowledge the support by the projects AYA2010-15196 from the Spanish Ministerio de Ciencia e Innovacion and TIC 114 and PO08-TIC-3531 from Junta de Andalucia. AMI acknowledges support from Agence Nationale de la Recherche through the STILISM project (ANR-12-BS05-0016-02). M.M. acknowledges financial support from AYA2010-21887-004-02 from the Ministerio de Economia y Competitividad. PSB acknowledges support from the Ramon y Cajal program, grant ATA2010-21322-C03-02 from the Spanish Ministry of Economy and Competitiveness (MINECO). C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. V.W. acknowledges support from the European Research Council Starting Grant (SEDMorph P.I. V. Wild) and European Career Re-integration Grant (Phiz-Ev P.I. V. Wild). YA acknowledges financial support from the Ramon y Cajal programme (RyC-2011-09461) and project AYA2013-47742-C4-3-P, both managed by the Ministerio de Economia y Competitividad, as well as the >Study of Emission-Line Galaxies with Integral Field Spectroscopy> (SELGIFS) programme, funded by the EU (FP7-PEOPLE-2013-IRSES-612701) within the Marie-Sklodowska-Curie Actions scheme. ROM acknowledges support from CAPES (Brazil) through a PDJ fellowship from project 88881.030413/2013-01, program CSF-PVE.Peer Reviewe

CALIFA, the Calar Alto Legacy Integral Field Area survey: III. Second public data release

García-Benito, R. et. al.© ESO, 2015. This paper describes the Second Public Data Release (DR2) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. The data for 200 objects are made public, including the 100 galaxies of the First Public Data Release (DR1). Data were obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto observatory. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the wavelength range 3745-7500 Å with a spectral resolution of 6.0 Å (FWHM); and (ii) a medium-resolution V1200 setup covering the wavelength range 3650-4840 Å with a spectral resolution of 2.3 Å (FWHM). The sample covers a redshift range between 0.005 and 0.03, with a wide range of properties in the color-magnitude diagram, stellar mass, ionization conditions, and morphological types. All the cubes in the data release were reduced with the latest pipeline, which includes improvedspectrophotometric calibration, spatial registration, and spatial resolution. The spectrophotometric calibration is better than 6% and the median spatial resolution is 2.4. In total, the second data release contains over 1.5 million spectra.R.G.B., R.G.D., and E.P. are supported by the Spanish Ministerio de Ciencia e Innovacion under grant AYA2010-15081. S.Z. is supported by the EU Marie Curie Integration Grant >SteMaGE> Nr. PCIG12-GA-2012-326466 (Call Identifier: FP7-PEOPLE-2012 CIG). J.F.B. acknowledges support from grants AYA2010-21322-C03-02 and AIB-2010-DE-00227 from the Spanish Ministry of Economy and Competitiveness (MINECO), as well as from the FP7 Marie Curie Actions of the European Commission, via the Initial Training Network DAGAL under REA grant agreement number 289313. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC12009, awarded to The Millennium Institute of Astrophysics, M.A.S.L.G. also acknowledges support by CONICYT through FONDECYT grant 3140566. A.G. acknowledges support from the FP7/2007-2013 under grant agreement n. 267251 (AstroFIt). J.M.G. acknowledges support from the Fundacao para a Ciencia e a Tecnologia (FCT) through the Fellowship SFRH/BPD/66958/2009 from FCT (Portugal) and research grant PTDC/FIS-AST/3214/2012. RAM was funded by the Spanish programme of International Campus of Excellence Moncloa (CEI). J.M.A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). I.M., J.M. and A.d.O. acknowledge the support by the projects AYA2010-15196 from the Spanish Ministerio de Ciencia e Innovacion and TIC 114 and PO08-TIC-3531 from Junta de Andalucia. AMI acknowledges support from Agence Nationale de la Recherche through the STILISM project (ANR-12-BS05-0016-02). M.M. acknowledges financial support from AYA2010-21887-C04-02 from the Ministerio de Economia y Competitividad. P.P. is supported by an FCT Investigador 2013 Contract, funded by FCT/MCTES (Portugal) and POPH/FSE (EC). P.P. acknowledges support by FCT under project FCOMP-01-0124-FEDER-029170 (Reference FCT PTDC/FIS-AST/3214/2012), funded by FCT-MEC (PIDDAC) and FEDER (COMPETE). T.R.L. thanks the support of the Spanish Ministerio de Educacion, Cultura y Deporte by means of the FPU fellowship. PSB acknowledges support from the Ramon y Cajal program, grant ATA2010-21322-C03-02 from the Spanish Ministry of Economy and Competitiveness (MINECO). C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. V.W. acknowledges support from the European Research Council Starting Grant (SEDMorph P.I. V. Wild) and European Career Re-integration Grant (Phiz-Ev P.I.V. Wild). Y.A. acknowledges financial support from the Ramon y Cajal programme (RyC-2011-09461) and project AYA2013-47742-C4-3-P, both managed by the Ministerio de Economia y Competitividad, as well as the >Study of Emission-Line Galaxies with Integral-Field Spectroscopy> (SELGIFS) programme, funded by the EU (FP7-PEOPLE-2013-IRSES-612701) within the Marie-Sklodowska-Curie Actions schemePeer Reviewe

The CALIFA survey across the Hubble sequence: Spatially resolved stellar population properties in galaxies

© ESO, 2015. Various different physical processes contribute to the star formation and stellar mass assembly histories of galaxies. One important approach to understanding the significance of these different processes on galaxy evolution is the study of the stellar population content of today's galaxies in a spatially resolved manner. The aim of this paper is to characterize in detail the radial structure of stellar population properties of galaxies in the nearby universe, based on a uniquely large galaxy sample, considering the quality and coverage of the data. The sample under study was drawn from the CALIFA survey and contains 300 galaxies observed with integral field spectroscopy. These cover a wide range of Hubble types, from spheroids to spiral galaxies, while stellar masses range from MBlack star ∼ 109 to 7 × 1011 M⊙. We apply the fossil record method based on spectral synthesis techniques to recover the following physical properties for each spatial resolution element in our target galaxies: the stellar mass surface density (μBlack star), stellar extinction (AV), light-weighted and mass-weighted ages ('log age'L, 'log age'M), and mass-weighted metallicity ('log ZBlack star'M). To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd). We confirm that more massive galaxies are more compact, older, more metal rich, and less reddened by dust. Additionally, we find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble type: earlier types are more compact, older, and more metal rich for a given MBlack star, which is evidence that quenching is related to morphology, but not driven by mass. Negative gradients of 'log age'L are consistent with an inside-out growth of galaxies, with the largest 'log age'L gradients in Sb-Sbc galaxies. Further, the mean stellar ages of disks and bulges are correlated and with disks covering a wider range of ages, and late-type spirals hosting younger disks. However, age gradients are only mildly negative or flat beyond R ∼ 2 HLR (half light radius), indicating that star formation is more uniformly distributed or that stellar migration is important at these distances. The gradients in stellar mass surface density depend mostly on stellar mass, in the sense that more massive galaxies are more centrally concentrated. Whatever sets the concentration indices of galaxies obviously depends less on quenching/morphology than on the depth of the potential well. There is a secondary correlation in the sense that at the same MBlack star early-type galaxies have steeper gradients. The μBlack star gradients outside 1 HLR show no dependence on Hubble type. We find mildly negative 'log ZBlack star'M gradients, which are shallower than predicted from models of galaxy evolution in isolation. In general, metallicity gradients depend on stellar mass, and less on morphology, hinting that metallicity is affected by both - the depth of the potential well and morphology/quenching.Support from the Spanish Ministerio de Economia y Competitividad, through projects AYA2010-15081 (PI R.G.D.), and Junta de Andalucia FQ1580 (PI R.G.D.), AYA2010-22111-C03-03, and AYA2010-10904E (S.F.S.). We also thank the Viabilidad, Diseno, Acceso y Mejora funding program, ICTS-2009-10, for funding the data acquisition of this project. R.C.F. thanks the hospitality of the IAA and the support of CAPES and CNPq. R.G.D. acknowledges the support of CNPq (Brazil) through Programa Ciencia sem Fronteiras (401452/2012-3). A.G. acknowledges support from EU FP7/2007-2013 under grant agreement n.267251 (AstroFIt) and from the EU Marie Curie Integration Grant >SteMaGE> Nr. PCIG12-GA-2012-326466. C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. E.P. acknowledges support from the Guillermo Haro program at INAOE. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. L.G. acknowledges support by CONICYT through FONDECYT grant 3140566. J.I.P. acknowledges financial support from the Spanish MINECO under grant AYA2010-21887-C04-01 and from Junta de Andalucia Excellence Project PEX2011-FQM7058. I.M., J.M. and A.d.O. acknowledge support from the project AYA2013-42227-P. RAM is funded by the Spanish program of International Campus of Excellence Moncloa (CEI). J.M. A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild).Peer Reviewe

Integral Field Spectroscopy of (U) LIRGs and Post-Starburst QSOs: the role of mergers in galaxy evolution

In this thesis we have characterized and compared the star formation histories, average stellar population properties and ionized gas properties in two small samples of galaxies in different stages across the merger sequence, three LIRGs (the two pre-mergers IC 1623 and NGC 6090 and the merger NGC 2623) and nine PSQSOs, by analysing high quality Integral Field Spectroscopy (IFS) data in the rest-frame optical range 3700 - 7000 °A, and high resolution HST imaging. Additionally, for NGC 2623 we have narrow band imaging in Hα and [NII]λ6583 from OSIRIS@GTC Tunable Filters, that allow us to study the outer parts of the tidal tails. The results from the LIRGs and PSQSOs have been compared with control Sbc and Sc galaxies from CALIFA survey. The methodology applied has been the same for all, a full spectral fitting analysis was performed using the Starlight code with a combination of single stellar population (SSP) models from the literature. With our data we find a evolutionary sequence related to the merger progression that is in agreement with recent simulations. In the initial stages (pre-mergers) the induced star formation (SF) is extended, and enhanced, on average, by a factor ∼ 4 with respect to the control spirals. When we resolve it spatially we find that for IC 1623 W the enhancement is the same in the central region and in the disk (by a factor 7), while for NGC 6090 NE the enhancement is higher in the central region (by a factor 9), still significant at one half light radius (by a factor 5) and less significant in the ”disk” (only enhanced by a factor 1.5). Attending to the importance of stellar populations ∼ 300 Myr, we find that the merger-induced star formation started earlier in IC 1623 W than in NGC 6090 NE. In more advanced mergers, as NGC 2623, we find that most of the young SF is concentrated in the central region, enhanced by a factor 9 with respect to control spirals. However, there exists also lower level of star formation in the outer parts, enhanced by . 3 in comparison to spirals. From the global average across the whole galaxy we find than is a factor ∼ 3 higher than in spirals. In addition, in NGC 2623 we detect fossil emission of an extended merger-induced burst occurred ∼ 1.5 Gyr ago, probably when it was at the pre-merger stage. The mass formed during this first burst is enhanced by a factor 2 both in the center and in the outer parts with respect to the mass formed in the same period in isolated spirals. From the average of the nine PSQSOs we find that, both in terms of light and mass, the SFHs are comparable to NGC 2623 ones. Attending to the average ages we found that they are ∼ 400 Myr older than NGC 2623. It seems that PSQSOs are slightly more evolved, however, given the uncertainties related to the model base choice, and the heterogeneity of the sample, we can not confirm exactly to what degree. We note, however, that both present a significant contribution to mass of stellar populations younger than 1.5 Gyr, which is not present in the pre-merger LIRGs. However, we think that the current starburst seen in the pre-mergers is in fact forming this intermediate age mass that will look like NGC 2623 in . 1.5 Gyr. The stellar mass in SSPs younger than 1.5 Gyr is ∼ 6.6 × 109 M⊙ (Chabrier IMF) in NGC 2623 and ∼ 1010 M⊙ in the PSQSOs, hence, we find that if the pre-merger LIRGs keep forming stars at the current rate ∼ 16 M⊙ yr−1 during ∼ 400 - 600 Myr, then they can account for the mass in NGC 2623 and PSQSOs. This time is approximately consistent with the 500 Myr upper limit expected for the duration of merger triggered starbursts from numerical simulations of mergers. With respect to the evolution from NGC 2623 to PSQSO, we note that in few 100 Myr molecular outflows like the ones in some U/LIRGs would be able to remove dust from the core leaving the AGN uncovered. This is in consistent with the average time delay of ∼ 400 Myr found by us between NGC 2623 and the PSQSOs. Finally, given the stellar masses measured in the LIRGs and in the PSQSOs, most of them . 1011 M⊙, we find that they will form ellipticals of intermediate mass (∼ 1011 M⊙), or the core of future giant ellipticals, in agreement with the major-merger evolutionary scenario.Tesis Univ. Granada. Programa Oficial de Doctorado en: Física y Ciencias del Espaci

Simultaneous spectroscopic and photometric analysis of galaxies with STARLIGHT: CALIFA+GALEX

We present an extended version of the spectral synthesis code STARLIGHT designed to incorporate both λ-by-λ spectra and photometric fluxes in the estimation of stellar population properties of galaxies. The code is tested with simulations and data for 260 galaxies culled from the Calar Alto Legacy Integral Field Area (CALIFA) survey, spatially matching the 3700-7000 Å optical data cubes to Galaxy Evolution Explorer (GALEX) near-ultraviolet (NUV) and farultraviolet (FUV) images. The sample spans E-Sd galaxies with masses from 10 to 10M⊙ and stellar populations all the way from star-forming to old, passive systems. Comparing results derived from purely optical fits with those which also consider the NUV and FUV data we find that the following. (1) The new code is capable of matching the input ultraviolet (UV) data within the errors while keeping the quality of the optical fit essentially unchanged. (2) Despite being unreliable predictors of the UV fluxes, purely optical fits yield stellar population properties which agree well with those obtained in optical+UV fits for nearly 90 per cent of our sample. (3) The addition of UV constraints has little impact on properties such as stellar mass and dust optical depth. Mean stellar ages and metallicities also remain nearly the same for most galaxies, the exception being low-mass, late-type galaxies, which become older and less enriched due to rearrangements of their youngest populations. (4) The revised ages are better correlated with observables such as the 4000 Å break index, and the NUV - r and u - r colours, an empirical indication that the addition of UV constraints helps mitigating the effects of age-metallicity-extinction degeneracies. © 2016 The Authors.Support from the Spanish Ministerio de Econom´ıa y Competitividad, through projects AYA2014-57490-P, AYA2010-15081 (PI RGD), Junta de Andaluc´ıa FQ1580 (PI RGD), AYA2010-22111-C03-03, AYA2010-10904E (SFS), and short-term research FPI program grants EEBB-I-2013-07071 and EEBB-I-2014-08601. SFS thanks the CONACYT-125180 and DGAPA-IA100815 projects for providing him support in this study. We also thank the Viabilidad, Diseno, ˜ Acceso y Mejora funding program, ICTS-2009-10, for funding the data acquisition of this project. Support from the Brazilian Science Galaxy spectrophotometry with STARLIGHT 199 without borders program, as well as CNPq and CAPES is duly acknowledged. This research made use of Montage. It is funded by the National Science Foundation under Grant Number ACI- 1440620, and was previously funded by the National Aeronautics and Space Administration’s Earth Science Technology Office, Computation Technologies Project, under Cooperative Agreement Number NCC5-626 between NASA and the California Institute of TechnologyPeer Reviewe

The spatially resolved star formation history of CALIFA galaxies: Cosmic time scales

This paper presents the mass assembly time scales of nearby galaxies observed by CALIFA at the 3.5 m telescope in Calar Alto. We apply the fossil record method of the stellar populations to the complete sample of the 3rd CALIFA data release, with a total of 661 galaxies, covering stellar masses from 10 to 10M and a wide range of Hubble types. We apply spectral synthesis techniques to the datacubes and process the results to produce the mass growth time scales and mass weighted ages, from which we obtain temporal and spatially resolved information in seven bins of galaxy morphology (E, S0, Sa, Sb, Sc, and Sd) and six bins of stellar mass and stellar mass surface density. We use three different tracers of the spatially resolved star formation history (mass assembly curves, ratio of half mass to half light radii, and mass-weighted age gradients) to test if galaxies grow inside-out, and its dependence with galaxy stellar mass, stellar mass surface density, and morphology. Our main results are as follows: (a) the innermost regions of galaxies assemble their mass at an earlier time than regions located in the outer parts; this happens at any given stellar mass (M), stellar mass surface density (Σ), or Hubble type, including the lowest mass systems in our sample. (b) Galaxies present a significant diversity in their characteristic formation epochs for lower-mass systems. This diversity shows a strong dependence of the mass assembly time scales on Σ and Hubble type in the lower-mass range (10 to 10), but a very mild dependence in higher-mass bins. (c) The lowest half mass radius (HMR) to half light radius (HLR) ratio is found for galaxies between 10 and 10M, where galaxies are 25% smaller in mass than in light. Low-mass galaxies show the largest ratio with HMR/HLR ∼ 0.89. Sb and Sbc galaxies present the lowest HMR/HLR ratio (0.74). The ratio HMR/HLR is always, on average, below 1, indicating that galaxies grow faster in mass than in light. (d) All galaxies show negative (log age) gradients in the inner 1 HLR. The profile flattens (slope less negative) with increasing values of Σ. There is no significant dependence on M within a particular Σ bin, except for the lowest bin, where the gradients becomes steeper. (e) Downsizing is spatially preserved as a function of M and Σ, but it is broken for E and SO where the outer parts are assembled in later epochs than Sa galaxies. These results suggest that independently of their stellar mass, stellar mass surface density, and morphology, galaxies form inside-out on average. © ESO, 2017.CALIFA is the first legacy survey carried out at Calar Alto. The CALIFA collaboration would like to thank the IAA-CSIC and MPIA-MPG as major partners of the observatory, and CAHA itself, for the unique access to telescope time and support in manpower and infrastructures. We also thank the CAHA staff for their dedication to this project. We are grateful for the support of the IAA Computing group. Support from the Spanish Ministerio de Economia y Competitividad, through projects AYA2016-77846-P, AYA2014-57490-P, AYA2010-15081, and Junta de Andalucia P12-FQM-2828. R.C.F. acknowledges support from CNPq and FAPESC. S.F.S. thanks PAPIIT-DGAPA-IA101217 project and CONACYT-IA-180125. This research made use of Python (http://www.python.org); Numpy (Van Der Walt et al. 2011), Astropy (Astropy Collaboration et al. 2013), Pandas (McKinney 2011), Matplotlib (Hunter 2007), and Seaborn (Waskom et al. 2016). We thank the referee for very useful comments that improved the presentation of the paper.Peer reviewe

Spatially-resolved star formation histories of CALIFA galaxies: Implications for galaxy formation

This paper presents the spatially resolved star formation history (SFH) of nearby galaxies with the aim of furthering our understanding of the different processes involved in the formation and evolution of galaxies. To this end, we apply the fossil record method of stellar population synthesis to a rich and diverse data set of 436 galaxies observed with integral field spectroscopy in the CALIFA survey. The sample covers a wide range of Hubble types, with stellar masses ranging from M ∼ 10 to 7 × 10 M. Spectral synthesis techniques are applied to the datacubes to retrieve the spatially resolved time evolution of the star formation rate (SFR), its intensity (Σ), and other descriptors of the 2D SFH in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd) and five bins of stellar mass. Our main results are that (a) galaxies form very fast independently of their current stellar mass, with the peak of star formation at high redshift (z > 2). Subsequent star formation is driven by M and morphology, with less massive and later type spirals showing more prolonged periods of star formation. (b) At any epoch in the past, the SFR is proportional to M, with most massive galaxies having the highest absolute (but lowest specific) SFRs. (c) While today, the Σ is similar for all spirals and significantly lower in early-type galaxies (ETG), in the past, the Σ scales well with morphology. The central regions of today's ETGs are where the Σ reached the highest values (> 10 M Gyr pc), similar to those measured in high-redshift star-forming galaxies. (d) The evolution of Σ in Sbc systems matches that of models for Milky Way-like galaxies, suggesting that the formation of a thick disk may be a common phase in spirals at early epochs. (e) The SFR and Σ in outer regions of E and S0 galaxies show that they have undergone an extended phase of growth in mass between z = 2 and 0.4. The mass assembled in this phase is in agreement with the two-phase scenario proposed for the formation of ETGs. (f) Evidence of an early and fast quenching is found only in the most massive (M > 2 × 10 M) E galaxies of the sample, but not in spirals of similar mass, suggesting that halo quenching is not the main mechanism for the shut down of star formation in galaxies. Less massive E and disk galaxies show more extended SFHs and a slow quenching. (g) Evidence of fast quenching is also found in the nuclei of ETG and early spirals, with SFR and Σ indicating that they can be the relic of the >red nuggets> detected at high redshift.© ESO, 2017.Support from the Spanish Ministerio de Economia y Competitividad, through projects AYA2016-77846-P, AYA2014-57490-P, AYA2010-15081, and Junta de Andalucia FQ1580, AYA2010-22111-C03-03, AYA2010-10904E, AYA2013-42227P, RyC-2011-09461, AYA2013-47742-C4-3-P, EU SELGIFS exchange programme FP7-PEOPLE-2013-IRSES-612701, CONACYT-125180, DGAPA-IA100815, and PAPIIT-DGAPA-IA101217. We also thank the Viabilidad, Diseno, Acceso y Mejora funding program, ICTS-2009-10, for funding the data acquisition of this project. A.L.d.A., E.A.D.L. and R.C.F. thanks for the hospitality of the IAA and the support of CNPq. R.G.D. acknowledges the support of CNPq (Brazil) through Programa Ciencia sem Fronteiras (401452/2012-3). C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912.Peer Reviewe

Tracing kinematic (mis)alignments in CALIFA merging galaxies: Stellar and ionized gas kinematic orientations at every merger stage

© 2015 ESO. We present spatially resolved stellar and/or ionized gas kinematic properties for a sample of 103 interacting galaxies, tracing all merger stages: close companions, pairs with morphological signatures of interaction, and coalesced merger remnants. In order to distinguish kinematic properties caused by a merger event from those driven by internal processes, we compare our galaxies with a control sample of 80 non-interacting galaxies. We measure for both the stellar and the ionized gas components the major (projected) kinematic position angles (PAkin, approaching and receding) directly from the velocity distributions with no assumptions on the internal motions. This method also allow us to derive the deviations of the kinematic PAs from a straight line (δPAkin). We find that around half of the interacting objects show morpho-kinematic PA misalignments that cannot be found in the control sample. In particular, we observe those misalignments in galaxies with morphological signatures of interaction. On the other hand, thelevel of alignment between the approaching and receding sides for both samples is similar, with most of the galaxies displaying small misalignments. Radial deviations of the kinematic PA orientation from a straight line in the stellar component measured by δPAkin are large for both samples. However, for a large fraction of interacting galaxies the ionized gas δPAkin is larger than the typical values derived from isolated galaxies (48%), indicating that this parameter is a good indicator to trace the impact of interaction and mergers in the internal motions of galaxies. By comparing the stellar and ionized gas kinematic PA, we find that 42% (28/66) of the interacting galaxies have misalignments larger than 16°, compared to 10% from the control sample. Our results show the impact of interactions in the motion of stellar and ionized gas as well as the wide the variety of their spatially resolved kinematic distributions. This study also provides a local Universe benchmark for kinematic studies in merging galaxies at high redshift.J.B.-B. and B.G.-L acknowledge support from the Plan Nacional de I+D+i (PNAYA) funding programs (AYA2012-39408-C02-02-1 and AYA2013-41656-P) of Spanish Ministry of Economy and Competitiveness (MINECO). J.F.B. acknowledges support from the Plan Nacional de I+D+i (PNAYA) funding programs from MINECO (AYA2013-48226-03-1-P, RAVET) A.M.-I. acknowledges support from Agence Nationale de la Recherche through the STILISM project (ANR-12-BS05-0016-02) and from BMBF through the Erasmus-F project (grant number 05 A12BA1). I.M. acknowledges financial support by MINECO grant AYA 2010-15169, Junta de Andalucia TIC114 and Proyecto de Excelencia de la Junta de Andalucia P08-TIC-03531. J.M.A. and V.W. acknowledge support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild). J.I.P. acknowledges financial support from the Spanish MINECO under grant AYA2013-47742-C04-1 and from Junta de Andalucia Excellence Project PEX2011-FQM7058. R.A.M is funded by the Spanish program of International Campus of Excellence Moncloa (CEI). L.V.M. acknowledges support from the grant AYA2011-30491-C02-01 co-financed by MICINN and FEDER funds, and the Junta de Andalucia (Spain) grants P08-FQM-4205 and TIC-114.Peer Reviewe