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We use the Illustris-1 simulation to explore the capabilities of the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) data to analyze the stellar populations in high-redshift galaxies, taking advantage of the combined depth, spatial resolution, and wavelength coverage. For that purpose, we use simulated broadband ACS, WFC3, and NIRCam data and two-dimensional stellar population synthesis (2D-SPS) to derive the integrated star formation history (SFH) of massive (M_(*) > 10^(10) Mꙩ) simulated galaxies at 1 < z < 4 that evolve into a local M_(*) > 10^(11) Mꙩ galaxy. In particular, we explore the potential of HST and JWST data sets reaching a depth similar to those of the CANDELS and ongoing CEERS observations, respectively, and concentrate on determining the capabilities of this data set for characterizing the first episodes in the SFH of local M_(*) > 10^(11) Mꙩ galaxies by studying their progenitors at z > 1. The 2D-SPS method presented in this paper has been calibrated to robustly recover the cosmic times when the first star formation episodes occurred in massive galaxies, i.e., the first stages in their integrated SFHs. In particular, we discuss the times when the first 1%–50% of their total stellar mass formed in the simulation. We demonstrate that we can recover these ages with typical median systematic offset of less than 5% and scatter around 20%–30%. According to our measurements on Illustris data, we are able to recover that local M_(*) > 10^(11) Mꙩ galaxies would have started their formation by z = 16, forming the first 5% of their stellar mass present at z ∼ 1 by z = 4.5, 10% by z = 3.7, and 25% by z = 2.7.

We investigate the nature of the relations between black hole (BH) mass (M_(BH)) and the central velocity dispersion (σ) and, for core-S´ersic galaxies, the size of the depleted core (R_(b)). Our sample of 144 galaxies with dynamically determined M_(BH) encompasses 24 core-Sérsic galaxies, thought to be products of gas-poor mergers, and reliably identified based on high-resolution HST imaging. For core-S´ersic galaxies—i.e., combining normal-core (R_(b) < 0.5 kpc) and large-core galaxies (R_(b) ˃̰ 0.5 kpc), we find that M_(BH) correlates remarkably well with R_(b) such that M_(BH) ∝ R^(1.20±0.14)_(b) (rms scatter in log M_(BH) of ∆_(rms) ∼ 0.29 dex), confirming previous works on the same galaxies except three new ones. Separating the sample into S´ersic, normal-core and large-core galaxies, we find that S´ersic and normal-core galaxies jointly define a single log-linear M_(BH) − σ relation M_(BH) ∝ σ^(4.88±0.29) with ∆_(rms) ∼ 0.47 dex, however, at the high-mass end large-core galaxies (four with measured M_(BH)) are offset upward from this relation by (2.5 − 4) × σ_(s), explaining the previously reported steepening of the M_(BH) − σ relation for massive galaxies. Large-core spheroids have magnitudes M_(V) ˂̰ −23.50 mag, half-light radii R_(e) ˃̰ 10 kpc and are extremely massive M * ˃̰ 10^(12)Mꙩ. Furthermore, these spheroids tend to host ultramassive BHs (M_(BH) ˃̰ 10^(10)Mꙩ) tightly connected with their R_(b) rather than σ. The less popular M_(BH) – R_(b) relation exhibits ∼ 62% less scatter in log M_(BH) than the M_(BH – σ) relations. Our findings suggest that large-core spheroids form via multiple major ‘dry’ merger events involving super/ultramassive BHs, consistent with the flattening of the σ – L_(V) relation observed at M_(V) ˂̰ −23.5 mag.

MEGARA is a third generation spectrograph for the Spanish 10.4m telescope (GTC) providing two observing modes: a large central Integral Field Unit (IFU), called the Large Compact Bundle (LCB), covering a FOV of 12.5 × 11.3 arcsec^(2) , and a Multi-Object Spectrograph (MOS) with a FOV of 3.5 × 3.5 arcmin^(2) . MEGARA will observe the whole visible range from 3650A to 10000A allowing different spectral resolutions (low, medium and high) with R = 6000, 11000 and 18000 respectively. The dispersive elements are placed at the spectrograph pupil position in the path of the collimated beam and they are composed of a set of volume phase hologram gratings (VPHs) sandwiched between two flat windows and coupled in addition to two prisms in the case of the medium- and high-resolution units. We will describe the tests and setups developed to check the requirements of all units, as well as the obtained performance at laboratory.

We present PIPE3D, an analysis pipeline based on the FIT3D fitting tool, developed to explore the properties of the stellar populations and ionized gas of integral field spectroscopy (IFS) data. PIPE3D was created to provide coherent, simple to distribute, and comparable dataproducts, independently of the origin of the data, focused on the data of the most recent IFU surveys (e.g., CALIFA, MaNGA, and SAMI), and the last generation IFS instruments (e.g., MUSE). In this article we describe the different steps involved in the analysis of the data, illustrating them by showing the dataproducts derived for NGC 2916, observed by CALIFA and P-MaNGA. As a practical example of the pipeline we present the complete set of dataproducts derived for the 200 datacubes that comprises the V500 setup of the CALIFA Data Release 2 (DR2), making them freely available through the network. Finally, we explore the hypothesis that the properties of the stellar populations and ionized gas of galaxies at the effective radius are representative of the overall average ones, finding that this is indeed the case.

We present an improved version of FIT3D, a fitting tool for the analysis of the spectroscopic properties of the stellar populations and the ionized gas derived from moderate resolution spectra of galaxies. This tool was developed to analyze integral field spectroscopy data and it is the basis of PIPE3D, a pipeline used in the analysis of CALIFA, MaNGA, and SAMI data. We describe the philosophy and each step of the fitting procedure. We present an extensive set of simulations in order to estimate the precision and accuracy of the derived parameters for the stellar populations and the ionized gas. We report on the results of those simulations. Finally, we compare the results of the analysis using FIT3D with those provided by other widely used packages, and we find that the parameters derived by FIT3D are fully compatible with those derived using these other tools.

Context. The star formation rate (SFR) is one of the main parameters used to analyze the evolution of galaxies through time. The need for recovering the light reprocessed by dust commonly requires the use of low spatial resolution far-infrared data. Recombination line luminosities provide an alternative, although uncertain dust-extinction corrections based on narrowband imaging or long-slit spectroscopy have traditionally posed a limit to their applicability. Integral field spectroscopy (IFS) is clearly the way to overcome this kind of limitation. Aims. We obtain integrated Hα, ultraviolet (UV) and infrared (IR)-based SFR measurements for 272 galaxies from the CALIFA survey at 0.005

While studies of gas-phase metallicity gradients in disc galaxies are common, very little has been done in the acquisition of stellar abundance gradients in the same regions. We present here a comparative study of the stellar metallicity and age distributions in a sample of 62 nearly face-on, spiral galaxies with and without bars, using data from the CALIFA survey. We measure the slopes of the gradients and study their relation with other properties of the galaxies. We find that the mean stellar age and metallicity gradients in the disc are shallow and negative. Furthermore, when normalized to the effective radius of the disc, the slope of the stellar population gradients does not correlate with the mass or with the morphological type of the galaxies. Contrary to this, the values of both age and metallicity at $\sim$2.5 scale-lengths correlate with the central velocity dispersion in a similar manner to the central values of the bulges, although bulges show, on average, older ages and higher metallicities than the discs. One of the goals of the present paper is to test the theoretical prediction that non-linear coupling between the bar and the spiral arms is an efficient mechanism for producing radial migrations across significant distances within discs. The process of radial migration should flatten the stellar metallicity gradient with time and, therefore, we would expect flatter stellar metallicity gradients in barred galaxies. However, we do not find any difference in the metallicity or age gradients in galaxies with without bars. We discuss possible scenarios that can lead to this absence of difference., 24 pages, 17 figures, accepted for publication in A&A

In these proceedings we summarize the characteristics and current status of MEGARA, the future optical IFU and MOS for the 10.4 m GTC. MEGARA is being built by a Consortium led by the UCM (Spain) that also includes the INAOE (Mexico), the IAA-CSIC (Spain) and the UPM (Spain). The MEGARA IFU offers two different bundles, one called LCB with a field-of-view of 14 x 12 arcsec^2 and a spaxel size of 0.685 arcsec yielding spectral resolutions between R=6000-19000 and another one called SCB covering 10 x 8 arcsec^2 with 0.48 arcsec spaxels and resolutions R=8000-25000. The MOS component allows observing up to 100 targets in 3.5x3.5 arcmin^2. In September 2010 MEGARA was selected as the next optical spectrograph for GTC. Its PDR is scheduled for March 2012 with First Light on 2015.

We present the first public data release (DR1) of the Calar Alto Legacy Integral Field Area (CALIFA) survey. It consists of science-grade optical datacubes for the first 100 of eventually 600 nearby (0.005 < z < 0.03) galaxies, obtained with the integral-field spectrograph PMAS/PPak mounted on the 3.5 m telescope at the Calar Alto observatory. The galaxies in DR1 already cover a wide range of properties in color-magnitude space, morphological type, stellar mass, and gas ionization conditions. This offers the potential to tackle a variety of open questions in galaxy evolution using spatially resolved spectroscopy. Two different spectral setups are available for each galaxy, (i) a low-resolution V500 setup covering the nominal wavelength range 3745-7500 angstrom with a spectral resolution of 6.0 angstrom (FWHM), and (ii) a medium-resolution V1200 setup covering the nominal wavelength range 3650-4840 angstrom with a spectral resolution of 2.3 angstrom (FWHM). We present the characteristics and data structure of the CALIFA datasets that should be taken into account for scientific exploitation of the data, in particular the effects of vignetting, bad pixels and spatially correlated noise. The data quality test for all 100 galaxies showed that we reach a median limiting continuum sensitivity of 1.0 x 10(-18) erg s(-1) cm(-2) angstrom(-1) arcsec(-2) at 5635 angstrom and 2.2 x 10(-18) erg s(-1) cm(-2) angstrom(-1) arcsec(-2) at 4500 angstrom for the V500 and V1200 setup respectively, which corresponds to limiting r and g band surface brightnesses of 23.6 mag arcsec(-2) and 23.4 mag arcsec(-2), or an unresolved emission-line flux detection limit of roughly 1 x 10(-17) erg s(-1) cm(-2) arcsec(-2) and 0.6 x 10(-17) erg s(-1) cm(-2) arcsec(-2), respectively. The median spatial resolution is 3 ''.7, and the absolute spectrophotometric calibration is better than 15% (1 sigma). We also describe the available interfaces and tools that allow easy access to this first public CALIFA data at http://califa.caha.es/DR1.

We analyse the spectroscopic properties of thousands of H _Π regions identified in 38 face-on spiral galaxies. All galaxies were observed out to 2.4 effective radii using integral field spectroscopy (IFS) over the wavelength range ~3700 to ~6900 Å. The near uniform sample has been assembled from the PPAK IFS Nearby Galaxy (PINGS) survey and a sample described in Paper I. We develop a new automatic procedure to detect H_Π regions, based on the contrast of the H_α intensity maps extracted from the datacubes. Once detected, the algorithm provides us with the integrated spectra of each individual segmented region. In total, we derive good quality spectroscopic information for ~2600 independent H_Π regions/complexes. This is by far the largest H_Π region survey of its kind. Our selection criteria and the use of 3D spectroscopy guarantee that we cover the regions in an unbiased way. A well-tested automatic decoupling procedure has been applied to remove the underlying stellar population, deriving the main properties (intensity, dispersion and velocity) of the strongest emission lines in the considered wavelength range (covering from [O_Π] λ3727 to [S_Π] λ6731). A final catalogue of the spectroscopic properties of H_Π regions has been created for each galaxy, which includes information on morphology, spiral structure, gaskinematics, and surface brightness of the underlying stellar population. In the current study, we focus on the understanding of the average properties of the H_Π regions and their radial distributions. We find a significant change in the ionisation characteristics of H_Π regions within r < 0.25 re due to contamination from sources with different ionising characteristics, as we discuss. We find that the gas-phase oxygen abundance and the Hα equivalent width present a negative and positive gradient, respectively. The distribution of slopes is statistically compatible with a random Gaussian distribution around the mean value, if the radial distances are measured in units of the respective effective radius. No difference in the slope is found for galaxies of different morphologies, e.g. barred/non-barred, grand-design/flocculent. Therefore, the effective radius is a universal scale length for gradients in the evolution of galaxies. Some properties have a large variance across each object and between galaxies (e.g. electron density) without a clear characteristic value. But other properties are well described by an average value either galaxy by galaxy or among the different galaxies (e.g. dust attenuation).

The mechanism causing breaks in the radial surface brightness distribution of spiral galaxies is not yet well known. Despite theoretical efforts, there is not a unique explanation for these features and the observational results are not conclusive. In an attempt to address this problem, we have selected a sample of 34 highly inclined spiral galaxies present both in the Sloan Digital Sky Survey and in the Spitzer Survey of Stellar Structure in Galaxies. We have measured the surface brightness profiles in the five Sloan optical bands and in the 3.6µm Spitzer band. We have also calculated the color and stellar surface mass density profiles using the available photometric information, finding two differentiated features: an innermost break radius at distances of ∼ 8 ± 1 kpc [0.77 ± 0.06 R_25] and a second characteristic radius, or truncation radius, close to the outermost optical extent (∼ 14 ± 2 kpc [1.09 ± 0.05 R_25]) of the galaxy. We propose in this work that the breaks might be a phenomena related to a threshold in the star formation, while truncations are more likely a real drop in the stellar mass density of the disk associated with the maximum angular momentum of the stars.

A great deal of our understanding of star formation in the local universe has been built upon an extensive foundation of Hα observational studies. However, recent work in the ultraviolet (UV) with GALEX has shown that star formation rates (SFRs) inferred from Hα in galactic environments characterized by low stellar and gas densities tend to be less than those based on the UV luminosity. The origin of the discrepancy is actively debated because one possible explanation is that the stellar initial mass function is systematically deficient in high mass stars in such environments. In this contribution, we summarize our work on this topic using a dwarf galaxy dominated sample of ~ 300 late-type galaxies in the 11 Mpc Local Volume. The sample allows us to examine the discrepancy between Hα and UV SFRs using a statistical number of galaxies with activities less than 0.1 M_⨀ yr^-1 A range of potential causes for such an effect are reviewed. We find that while the IMF hypothesis is not inconsistent with our observations, alternate explanations remain that must be investigated further before a final conclusion can be drawn.

The Spitzer Survey of Stellar Structure in Galaxies (S^4G) is an Exploration Science Legacy Program approved for the Spitzer post-cryogenic mission. It is a volume-, magnitude-, and size-limited (d 30º, m_Bcorr 1’) survey of 2,331 galaxies using the Infrared Array Camera (IRAC) at 3.6 and 4.5μm. Each galaxy is observed for 240 s and mapped to ≤ 1.5×D_25. The final mosaicked images have a typical 1σ rms noise level of 0.0072 and 0.0093 MJy sr^−1 at 3.6 and 4.5μm, respectively. Our azimuthally-averaged surface brightness profile typically traces isophotes at μ_3.6μm(AB)(1σ)~27 mag arcsec^−2, equivalent to a stellar mass surface density of ~ 1 M_⊙pc^−2. S^4G thus provides an unprecedented data set for the study of the distribution of mass and stellar structures in the local Universe. This large, unbiased and extremely deep sample of all Hubble types from dwarfs to spirals to ellipticals will allow for detailed structural studies, not only as a function of stellar mass, but also as a function of the local environment. The data from this survey will serve as a vital testbed for cosmological simulations predicting the stellar mass properties of present-day galaxies. This paper introduces the survey, describes the sample selection, the significance of the 3.6 and 4.5μm bands for this study, and the data collection & survey strategy. We describe the S^4G data analysis pipeline and present measurements for a first set of galaxies, observed in both the cryogenic and warm mission phase of Spitzer. For every galaxy we tabulate the galaxy diameter, position angle, axial ratio, inclination at μ_3.6μm(AB)= 25.5 and 26.5 mag arcsec^−2 (equivalent to ≈ μ_B(AB)=27.2 and 28.2 mag arcsec^−2, respectively). These measurements will form the initial S^4G catalog of galaxy properties. We also measure the total magnitude and the azimuthally-averaged radial profiles of ellipticity, position angle, surface brightness and color. Finally, we deconstruct each galaxy using GALFIT into its main constituent stellar components: the bulge/spheroid, disk, bar, and nuclear point source, where necessary. Together these data products will provide a comprehensive and definitive catalog of stellar structures, mass and properties of galaxies in the nearby Universe and enable a variety of scientific investigations, some of which are highlighted in this introductory S^4G survey paper.

Spitzer Space Telescope Infrared Array Camera imaging provides an opportunity to study all known morphological types of galaxies in the mid-IR at a depth significantly better than ground-based near-infrared and optical images. The goal of this study is to examine the imprint of the de Vaucouleurs classification volume in the 3.6 μm band, which is the best Spitzer waveband for galactic stellar mass morphology owing to its depth and its reddening-free sensitivity mainly to older stars. For this purpose, we have prepared classification images for 207 galaxies from the Spitzer archive, most of which are formally part of the Spitzer Survey of Stellar Structure in Galaxies (S^4G), a Spitzer post-cryogenic ("warm") mission Exploration Science Legacy Program survey of 2331 galaxies closer than 40 Mpc. For the purposes of morphology, the galaxies are interpreted as if the images are blue light, the historical waveband for classical galaxy classification studies. We find that 3.6 μm classifications are well correlated with blue-light classifications, to the point where the essential features of many galaxies look very similar in the two very different wavelength regimes. Drastic differences are found only for the most dusty galaxies. Consistent with a previous study by Eskridge et al., the main difference between blue-light and mid-IR types is an ≈1 stage interval difference for S0/a to Sbc or Sc galaxies, which tend to appear "earlier" in type at 3.6 μm due to the slightly increased prominence of the bulge, the reduced effects of extinction, and the reduced (but not completely eliminated) effect of the extreme population I stellar component. We present an atlas of all of the 207 galaxies analyzed here and bring attention to special features or galaxy types, such as nuclear rings, pseudobulges, flocculent spiral galaxies, I0 galaxies, double-stage and double-variety galaxies, and outer rings, that are particularly distinctive in the mid-IR.

We summarize the main properties of the extended UV (XUV) emission found in roughly 30% of the nearby spiral galaxies observed by the GALEX satellite. Two different classes of XUV disks are identified, the Type 1 XUV disks where significant, structured UV-bright features are found beyond the classical azimuthally-averaged star-formation threshold, and the Type 2 XUV disks, which are characterized by very extended (seven times the area where most of the stellar mass is found), blue ((FUV-K)

We present recent results from several on-going studies: The first addresses the question of gas-density thresholds for star formation, as probed by the outer disks of normal nearby galaxies. The second concerns the observational evidence for the existence of gravitating non-luminous (GNL) galaxies, as predicted by most recent simulations of galaxy formation in Lambda-CDM cosmologies. We find that (1) If star formation is traced by far-ultraviolet light, then there is no evidence for a threshold to star formation at any gas density so far probed, and (2) there is no evidence for GNL galaxies gravitationally interacting with known optical systems based on the observations (a) that there are no ring galaxies without plausible optically visible intruders, (b) all peculiar galaxies in the Arp Atlas that are bodily distorted have nearby plausibly interacting companions, and (c) there are no convincingly distorted/peculiar galaxies within Karachentsev's sample of more than 1,000 apparently/optically isolated galaxies.

The [O ii]λ3727 emission line is frequently used as an indicator of the star formation rate (SFR) despite its complex dependence on metallicity and excitation conditions. We have analysed the properties of the [O II] and Hα emission lines for a complete sample of local Hα-selected galaxies, the Universidad Complutense de Madrid (UCM) survey. We find a large scatter in the [O II]/Hα line ratios, although the scatter in the extinction-corrected [O II]^0/Hα^0 ratio is considerably smaller. We also find that the [O II]/Hα ratios are reasonably well correlated with the absolute B- and K-band magnitudes and with EW([O II]). However, the extinction-corrected [O II]^0/Hα^0 ratio is largely independent of these quantities, indicating that extinction is the main driver of the correlations. These correlations allow us to statistically predict-with varying degrees of accuracy-the observed and extinction-corrected Hα fluxes from the observed [O II] flux using the information contained in EW([O II]) and/or the absolute magnitudes, but extreme caution is needed to make sure that the sample selection effects are correctly taken into account.

We have mapped the ^(12)CO J = 1-0 and J = 2-1 line emission in Markarian 86, one of the most metal- deficient blue compact dwarf galaxies so far detected in ^(12)CO. The ^(12)CO emission is distributed in a horseshoelike structure that follows the locus of the most recent star formation regions. The minimum in molecular line emission corresponds to the position of an older, massive nuclear starburst. The H_(2) mass of the galaxy [in the range of (0.4–5) x 10^(7) M☉] and its morphology have been compared with the predictions of hydrodynamic simulations of the evolution of the interstellar medium surrounding a nuclear starburst. These simulations suggest that the physical conditions in the gas swept out by the starburst could have led to the formation of the ring of molecular gas reported here. This result provides an attractive scenario for explaining the propagation (in a galactic scale) of the star formation in dwarf galaxies.

In this paper, continuation of Gil de Pat et al. (Paper I), we derive the main properties of the stellar populations in the Blue Compact Dwarf galaxy Mrk 86. Ages, stellar masses, metallicites and burst strengths have been obtained using the combination of Monte Carlo simulations, a maximum likelihood estimator and Cluster and Principal Component Analysis. The three stellar populations detected show well defined properties. We have studied the underlying stellar population, which shows an age between 5-13 Gyr and no significant color gradients. The intermediate aged (30 Myr old) central starburst show a very low dust extinction with high burst strength and high stellar mass content (∼9x10^6 M_⨀). Finally, the properties of 46 low-metallicity (∼1/10Z_⨀) star-forming regions were also studied. The properties derived suggest that the most recent star-forming activity in Mrk 86 was triggered by the evolution of a superbubble originated at the central starburst by the energy deposition of stellar winds and supernova explosions. This superbubble produced the blowout of a fraction of the interstellar medium at distances of about 1 kpc with high gas surface densities, leading to the activation of the star formation. Finally, different mechanisms for the star formation triggering in this massive central starburst are studied, including the merging with a low mass companion and the interaction with UGC 4278. We have assumed a distance to Mrk 86 of 6.9 Mpc.

We have obtained optical (BVR, [O III]ƛ 5007 Å and H_α), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk 86 (NGC 2537). In this paper, the first of two, we present optical-near-infrared colors and emission-line fluxes for the currently star-forming regions, intermediate aged starburst and underlying stellar population. We also describe the evolutionary synthesis models used in Paper II. The R and H_α luminosity distributions of the galaxy star-forming regions show maxima at M-R = -9.5^m and L_H_α = 10^37.3 ergs^-l. The underlying stellar population shows an exponential surface brigthness profile with central value, μ_E,0 = 21.5 mag arcsec^-2, and scale, α=0.88 kpc, both measured in the R-band image. In the galaxy outer regions, dominated by this component, no significant color gradients are observed. Finally, a complete set of evolutionary synthesis models have been developed, covering a wide range in metallicity, 1/50 Z_⨀< Z < 2 Z_⨀, and burst strength, 1-10^-4. These models include nebular continuum and recombination and forbidden-line emission.

En esta tesis doctoral se ha estudiado la historia de la formación estelar en la galaxia Mrk 86 como propotipo de la sgalaxias compactas azules o galaxias BCD. Se obtuvieron imágenes en diferentes bandas asó como espectros ópticos de resolución intermida y alta e imágenes de interferomtría Fabry-Pérot. La existencia de un gran número de regiones de formaciónestelar en esta galaxia nos permitió indagar sobre los posibles mecanismos de activacióny propagación de la formacióne stelar en las galaxias BCD. En primer lugar se desrrollaron un conjunto de modelos de síntesis evolutiva que incluyen la contribución de una población subyacente y un brote de formacióne stelar reciente. Se desarrolló así mismo un novedoso procedimiento de comparación entre nuestros observables y las predicciones de los modelos de síntesis evlutiva basado en el uso combinado de simulaciones de Monte Carlo, un estimador de máxima verosimilitud, análisis de agrupamiento y análisis de la componente principal PCA. Lea medida de los colores y flujos de líneas de emisión y su posterior comparación con nuestros modelos siguiendo dicho procedimiento de análisis nos permitieron derivar las edades, fuerzas de brote, abundancias metálicas y masas estelares de las regiones de formacióne stelar de esta galaxia. Se estudiaron también las propiedades de la población estelar subyacente a partir del análisis de los perfiles de color. Finanlmente, mediante las observaciones de espectroscopía óptica y de interferometría Fabry-Pérot se obtuvo el campo de velocidad radial y de dispersiónde velocidades del objeto. A partir de este campo de velocidad radial y del perfil de masa reconstuido para esta galaxia, se extrajeron improtantes conclusiones respecto a la distribución del gas ionizado. Estos resultados nos permitieron ahondar en las compresión de la historia de estas galaxias.

El Spitzer Survey of Stellar Structure in Galaxies (S4G) es una muestra limitada en volumen, en magnitud, y en tamaño, de galaxias cercanas de todos los tipos morfológicos dentro de un volumen de 40 Mpc, alcanzando una profundidad en brillo de superficie a 3.6 μm de μ[3.6] = 26.5 magarcsec−2 que corresponde a sondear las densidades de superficie de masa estelar menores a una masa solar por parsec cuadrado (Sheth et al., 2010). Partimos de la exploración S4G como nuestra muestra base, con 2352 galaxias para las cuales tenemos fotometría espacialmente resuelta en las bandas de 3,6 y 4,5 μm (Muñoz-Mateos et al., 2015). Luego recopilamos, reducimos y realizamos una fotometría cuidadosa en las imágenes de GALEX FUV y NUV disponibles públicamente.Al final, nuestra muestra GALEX/S4G comprende 1931 galaxias con fotometría de FUV y NUV,homogeneizadas a la fotometría de 3,6 y 4,5 μm. Esto corresponde a un 82% de cobertura de la muestra S4G, lo que significa que las estadísticas globales obtenidas en nuestra submuestra son similares a las de la muestra S4G y, en consecuencia, deberían ser representativas del Universo Local. El 18% faltante se debe al viñeteado de parte de estos objetos extensos en las imágenes(8%), o debido a la debilidad de sus contra-partidas UV de las que nuestro método de reducción no produjo fotometría confiable y que se excluyeron de la muestra final (10%). A pesar de la falta de datos para estas galaxias, el tamaño de la muestra se incrementa en diez veces con respecto a las muestras locales previamente disponibles, y es así el catálogo más grande de fotometría homogeneizada, resuelta espacialmente, desde el ultravioleta lejano (1516 Å) hasta el infrarrojo cercano (3,6 μm) de galaxias cercanas.Las imágenes GALEX/S4G procesadas, se complementan con otras imágenes y catálogos,como las imágenes de SDSS ugriz, las imágenes originales de Spitzer, los cubos HI y más. Los datos están disponibles públicamente a través del repositorio web de imágenes DAGAL (Detailed Anatomy of Galaxies, FP7 Marie Curie Actions project).

La formación estelar es uno de los procesos físicos más relevantes que determinan la formación de las galaxias, además de ser un factor esencial para su evolución. Esta Tesis Doctoral tiene como objetivo abordar el tema de la formación estelar en galaxias cercanas explorando distintas escalas físicas que van desde las galaxias como sistemas completos hasta las diferentes componentes estructurales que las forman, tales como bulbos, barras, y discos. La manera de proceder ha sido la siguiente, (I) se ha determinado la tasa de formación estelar actual en galaxias externas desde una perspectiva global, (II) se ha analizado la variación de la tasa de formación estelar a lo largo de las distintas estructuras internas que moldean las galaxias (bulbos, barras, y discos) con el objetivo de caracterizar los procesos de activación y quenching presentes, (III) finalmente, se proporcionan los valores de la densidad de la tasa de formación estelar para las galaxias y para sus componentes. La aparición de técnicas de espectroscopía de campo integral (del inglés, Integral Field Spectroscopy), que combinan al mismo tiempo las ventajas de la imagen y la espectroscopía clásica, es especialmente apropiada para el estudio en dos dimensiones de la estructura de las galaxias. Esta técnica permite tener información espacial y espectral de manera simultánea. Por ello, a lo largo de esta tesis, hemos usado los datos IFS de la exploración de galaxias cercanas CALIFA (Calar Alto Legacy Integral Field Area Survey)...

The Calar Alto Legacy Integral Field Area survey (CALIFA survey) has been designed to be the first survey to provide Integral Field Spectroscopy (IFS) data for a statistical sample of all galaxy types (~600 galaxies) in the Local Universe (0.005

El objetivo principal de esta tesis consiste en cuantificar la distribución espacial de las propiedades físicas de las estrellas, el gas y el polvo en galaxias cercanas, dado que son el registro fósil de su evolución pasada. En particular, nos centraremos sobre todo en las variaciones de estas propiedades con la distancia al centro de las galaxias espirales.[ABSTRACT]The main goal of this thesis is to quantify the spatial distribution of the physical properties of stars, gas and dust in nearby galaxies, since they are the fossil record of their past evolution. In particular, we will mostly focus on the variations of these properties with the galactocentric distance in spiral galaxies.