Search

Context.: The Spitzer Survey of Stellar Structure in Galaxies (S⁴G) is a detailed study of over 2300 nearby galaxies in the near-infrared (NIR), which has been critical to our understanding of the detailed structures of nearby galaxies. Because the sample galaxies were selected only using radio-derived velocities, however, the survey favored late-type disk galaxies over lenticulars and ellipticals. Aims: A follow-up Spitzer survey was conducted to rectify this bias, adding 465 early-type galaxies (ETGs) to the original sample, to be analyzed in a manner consistent with the initial survey. We present the data release of this ETG extension, up to the third data processing pipeline (P3): surface photometry. Methods: We produce curves of growth and radial surface brightness profiles (with and without inclination corrections) using reduced and masked Spitzer IRAC 3.6 μm and 4.5 μm images produced through Pipelines 1 and 2, respectively. From these profiles, we derive the following integrated quantities: total magnitudes, stellar masses, concentration parameters, and galaxy size metrics. We showcase NIR scaling relations for ETGs among these quantities. Results: We examine general trends across the whole S⁴G and ETG extension among our derived parameters, highlighting differences between ETGs and late-type galaxies (LTGs). The latter are, on average, more massive and more concentrated than LTGs, and subtle distinctions are seen among ETG morphological subtypes. We also derive the following scaling relations and compare them with previous results in visible light: mass-size (both half-light and isophotal), mass-concentration, mass-surface brightness (central, effective, and within 1 kpc), and mass-color. Conclusions: We find good agreement with previous works, though some relations (e.g., mass-central surface brightness) will require more careful multicomponent decompositions to be fully understood. The relations between mass and isophotal radius and between mass and surface brightness within 1 kpc, in particular, show notably small scatter. The former provides important constraints on the limits of size growth in galaxies, possibly related to star formation thresholds, while the latter–particularly when paired with the similarly tight relation for LTGs–showcases the striking self-similarity of galaxy cores, suggesting they evolve little over cosmic time. All of the profiles and parameters described in this paper will be provided to the community via the NASA/IPAC database on a dedicated website.

Comunicación de congreso, póster virtual presentado en el European Astronomical Society Annual Meeting (formerly known as EWASS) 28 June – 2 July 2021

Context: Stellar bars are known to gradually funnel gas to the central parts of disk galaxies. It remains a matter of debate why the distribution of ionized gas along bars and in the circumnuclear regions varies among galaxies. Aims: Our goal is to investigate the spatial distribution of star formation (SF) within bars of nearby low-inclination disk galaxies (i < 65°) from the S⁴G survey. We aim to link the loci of SF to global properties of the hosts (morphological type, stellar mass, gas fraction, and bar-induced gravitational torques), providing constraints for the conditions that regulate SF in bars. Methods: We use archival GALEX far- and near-UV imaging for 772 barred galaxies, and for a control sample of 423 non-barred galaxies. We also assemble a compilation of continuum-subtracted Hα images for 433 barred galaxies, 70 of which we produced from ancillary photometry and MUSE and CALIFA integral field unit data cubes. We employ two complementary approaches: (i) the analysis of bar (2D) and disk (1D) stacks built from co-added UV images (oriented and scaled with respect to the stellar bars and the extent of disks) of hundreds of galaxies that are binned based on their Hubble stage (T) and bar family; and (ii) the visual classification of the morphology of ionized regions (traced from Hα and UV data) in individual galaxies into three main SF classes: (A) only circumnuclear SF; (B) SF at the bar ends, but not along the bar; and (C) SF along the bar. Barred galaxies with active and passive inner rings are likewise classified. Results: Massive, gas-poor, lenticular galaxies typically belong to SF class A; this is probably related to bar-induced quenching of SF in the disk. The distribution of SF class B peaks for early- and intermediate-type spirals; this most likely results from the interplay of gas flow, shocks, and enhanced shear in massive centrally concentrated galaxies with large bar amplitudes (the latter is supported by the lack of a dip in the radial distribution of SF in non-barred galaxies). Late-type gas-rich galaxies with high gravitational torques are mainly assigned to SF class C; we argue that this is a consequence of low shear among the faintest galaxies. In bar stacks of spiral galaxies the UV emission traces the stellar bars and dominates on their leading side, as witnessed in simulations. Among early-type spirals the central UV emission is ∼0.5 mag brighter in strongly barred galaxies, relative to their weakly barred counterparts; this is probably related to the efficiency of strong bars sweeping the disk gas and triggering central starbursts. On the contrary, in later types the UV emission is stronger at all radii in strongly barred galaxies than in weakly barred and non-barred ones. We also show that the distributions of SF in inner-ringed galaxies are broadly the same in barred and non-barred galaxies, including a UV and Hα deficit in the middle part of the bar; this hints at the effect of resonance rings trapping gas that is no longer funneled inwards. Conclusions: Distinct distributions of SF within bars are reported in galaxies of different morphological types. Star-forming bars are most common among late-type gas-rich galaxies. Bars are important agents in the regulation of SF in disks.

Context.: Spiral galaxies are very common in the local Universe, but their formation, evolution, and interplay with bars remain poorly understood after more than a century of astronomical research on the topic. Aims: We use a sample of 391 nearby galaxies from the S⁴G survey to characterise the winding angle and amplitude of spiral arms as a function of disc properties, such as bar strength, in all kinds of spirals (grand-design, multi-armed, and flocculent). Methods: We derived global pitch angles in 3.6 μm de-projected images from (i) average measurements of individual logarithmic spiral segments, and (ii) for a subsample of 32 galaxies, from 2D Fourier analyses. The strength of spirals was quantified from the tangential-to-radial force ratio and from the normalised m = 2 Fourier density amplitudes. Results: In galaxies with more than one measured logarithmic segment, the spiral pitch angle varies on average by ∼10° between segments, but by up to ≳15 − 20°. The distribution of the global pitch angle versus Hubble type (T) is very similar for barred and non-barred galaxies when 1 ≲ T ≲ 5. Most spiral galaxies (> 90%) are barred for T > 5. The pitch angle is not correlated with bar strength, and only weakly with spiral strength. The amplitude of spirals is correlated with bar strength (and less tightly, with bar length) for all types of spirals. The mean pitch angle is hardly correlated with the mass of the supermassive black hole (estimated from central stellar velocity dispersion), with central stellar mass concentration, or with shear, questioning previous results in the literature using smaller samples. Conclusions: We do not find observational evidence that spiral arms are driven by stellar bars or by invariant manifolds. Most likely, discs that are prone to the development of strong bars are also reactive to the formation of prominent spirals, explaining the observed coupling between bar and spiral amplitudes.

Congreso Español sobre Cuevas Turísticas (7º. 2018. La Vall d’Uixó, Castellón). - Congreso Iberoamericano sobre Cuevas Turísticas (2º. 2018. La Vall d’Uixó, Castellón). - Texto en español con resumen y palabras claves en español e inglés., En este estudio se ha llevado a cabo el análisis de la diversidad microbiana presente en muestras de agua tomadas en la Cova des Pas de Vallgornera, situada en la zona sur de la isla de Mallorca y desarrollada en una plataforma carbonática arrecifal del Mioceno superior (Messiniense). El muestreo se realizó en la Galería “d’en Pau” ubicada en el centro del sistema endokárstico y a unos 2 km de boca de entrada, donde se tomaron muestras de gotas de agua de percolación, de los gours y de agua freática de acuífero en galerías semisumergidas. El estudio de la diversidad microbiana se realizó a partir de una aproximación metagenómica, que básicamente se trata de la secuenciación del ADN extraído de forma global de las muestras y que refleja la composición de los genomas y genes de los organismos mayoritarios. Se observó que las muestras que pertenecen al flujo de agua de percolación y los gours presentan una menor diversidad y comparten un mayor número de grupos taxonómicos que el agua procedente de las galerías Freáticas. Además, la metagenómica permitió la reconstrucción de los genomas microbianos (denominados MAGs) de las poblaciones más abundantes y permitió realizar estudios filogenéticos y hacer predicciones de su función metabólica a partir de la anotación de los genes detectados. De un total de 14 MAGs recuperados de las muestras de agua de percolación y los gours, los más abundantes se asociaron al género Acinetobacter, a la familia Sphingomonadaceae y a la clase Gammaproteobacteria. Los primeros, que serían los genomas más abundantes en estas muestras, y que tal vez conformarían dos especies distintas, se han asociado a procesos de biomineralización contribuyendo a la formación de estructuras calcáreas. Además, se obtuvieron MAGs casi completos de arqueas de la familia Nitrosophaeraceae y Nitrosopumilaceae, cuyo metabolismo quimiolitoautótrofo y oxidador de amonio podría ser responsable de parte de la producción primaria del sistema. Por otra parte, las muestras de agua freática presentaron una mayor diversidad y en la cual se reconstruyeron un total de 29 MAGs. Los mayoritarios se afiliaron a la familia Comamonadaceae y Nitrospiraceae y tres adicionales se afiliaron al dominio Arquea, como Candidatus Nitrosoarchaeum (el más abundante de las muestras) y Nitrososphaera del filo Thaumarchaeota, indicando también que en estos sistemas la producción primaria puede ser por oxidación de amonio como en las anteriores muestras = In the current study was analyzed the microbial diversity from the Cova des Pas de Vallgornera located in the southeast coast of Mallorca Island, which was developed in an arrecifal carbonate platform of the Upper Miocene (Messiniense). The samples were taken in “d’en Pau” gallery placed in the center of the endokarstic system and from 2 km of the entrance. There were taken samples from drip-water falling from speleothems, water from gours and phreatic lakes in semi-submerged galleries. The microbial diversity was evaluated by a metagenomic approach, which basically consisted on the sequencing of the total DNA extracted from the sample. Metagenomes mirrors the genomic composition and genes functions from the more abundant microbial populations. Drip-water and gours samples showed a lower diversity and shared a major number of taxonomic units than the sample related to phreatic lakes. Moreover, the metagenomes allowed the binning of the Metagenomes Assembly Genomes (called MAGs) from the most abundant populations and allowed perform phylogenetic studies and predict the metabolic function from the annotated genes. From a total of 14 MAGs recovered form drip-water samples and gours, the most abundant were associated to Acinetobacter genus, Sphingomonadaceae family and the class Gammaproteobacteria. Members of the genus Acinetobacter represented by 2 different species, has been associated to bio-mineralization processes contributing to calcareous structures formation. Additionally, related to Archaea domain, was recovered MAGs associated to the family Nitrosophaeraceae and Nitrosopumilaceae, whose chemolithoauthotroph and ammonia-oxidizing metabolism could be linked to part of the primary production in the cave. On the other hand, samples from phreatic lakes showed the higher diversity and it was possible to recover 29 MAGs. The most abundant MAGs were affiliated to the family Comamonadaceae and Nitrospiraceae. Additionally, 3 MAGs were affiliated to Archaea domain: Candidatus Nitrosoarchaeum, and Nitrososphaera of the phylum Thaumarchaeota, also indicating that in these systems the primary production can be associated by ammonia-oxidizing microorganisms as in the other samples., Instituto Mediterráneo de Estudios Avanzados, España, Unidad de Baleares, Instituto Geológico y Minero de España, España, Instituto Geológico y Minero de España, España

In this thesis we shed light on the formation and evolution of disk galaxies, which often host a stellar bar (about 2/3 of cases). In particular, we address the bar-driven secular evolution, that is, the steady redistribution of stellar and gaseous material through the disk induced by the bar torques and resonances. We characterize the mass distribution of the disks in the Spitzer Survey of Stellar Structure in Galaxies (S4G, Sheth et al. 2010) and study the properties of the different stellar structure components and the interplay between them. We use 3.6 μm photometry for ∼1300 face-on and moderately inclined disk galaxies to analyze the frequency, dimensions, orientations and shapes of stellar bars, spiral arms, rings, (ring)lenses, and barlenses (i.e. lens-like structures embedded in the bars). We calculate the strength of the bars in the S4G via ellipse fitting, Fourier decomposition of the galaxy images, and from the gravitational tangential-to-radial forces. We also estimate the stellar contribution to the circular velocity, allowing us to analyze the coupling between non-baryonic and stellar matter within the optical disk. We average stellar density profiles (1D), the disk(+bulge) component of the rotation curve, and stellar bars (2D) as a function of fundamental galaxy parameters. We complement the study with integral-field unit kinematic data from Seidel et al. (2015b) for a subsample of 16 S4G barred galaxies. We quantify the bar-induced perturbation strengths in the stellar and gaseous disk from the kinematics, and show that they agree with the estimates obtained from the images. We also use Hα Fabry-Perot observations from Erroz-Ferrer et al. (2015) for 29 S4G disk galaxies to study the inner slope of the rotation curves. We provide possible observational evidence for the growth of bars in a Hubble time. We demonstrate the role of bars causing the spreading of the disk and the enhancement of the central stellar concentration. Our observations support the idea that Boxy/Peanut bulges in face-on perspective manifest as barlenses, that are often identified in early-type galaxies hosting strong bars, and some of them also as inner lenses. We find that the amount of dark matter within the optical disk scales with the total stellar mass, as expected in the ΛCDM models. We also confirm that the observed inner velocity gradient is correlated with the central surface brightness, showing a strong connection between the inner shape of the potential well and the central stellar density. We show that disks and bars in early-type (T < 5 ≡ Sc) and late-type (T ≥ 5) disk galaxies, or alternatively in galaxies having total stellar masses greater or smaller than 1010 M\(\odot\), are characterized by very distinct properties. Late-type disks are less centrally concentrated (many galaxies are bulge-less) and present a larger halo-to-stellar mass ratio, what probably affects the disk stability properties. The detection of bars in late-type galaxies is strongly dependent on the identification criteria. On average, bars in early-type spirals (T = 0 − 2) are longer (both in physical units and relative to the disk) and have larger density amplitudes than the intermediate type spirals (T ≈ 5), and the bar lengths among the latest-types in the S4G are also larger. In comparison to earlier types, the bars in late-type systems show larger tangential-to-radial force ratios. This result holds even when the estimated dark halo effect is included., Short version (introduction only) of the PhD thesis (140 pages). Original papers are not included. We acknowledge financial support to the DAGAL network from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007- 2013/ under REA grant agreement number PITN-GA-2011-289313., {"references":["Díaz-García, S., Salo, H., Laurikainen, E., and Herrera-Endoqui, M. 2016b, A&A, 587, A160","Díaz-García, S., Salo, H., and Laurikainen, E., M. 2016a, A&A, 596, A84","Herrera-Endoqui, M., Díaz-García, S., Laurikainen, E., and Salo, H. 2015, A&A, 582, A86","Seidel, M. K., Falcón-Barroso, J., Martínez-Valpuesta, I., et al. 2015b, MNRAS, 451, 936","Erroz-Ferrer, S., Knapen, J. H., Leaman, R., et al. 2016, MNRAS, 458, 1199"]}