Suchergebnisse

Studies of gas-phase radial metallicity profiles in spirals published in the last decade have diminished the importance of galactic bars as agents that mix and flatten the profiles, contradicting results obtained in the 1990s. We have collected a large sample of 2831 published H ii region emission-line fluxes in 51 nearby galaxies, including objects both with and without the presence of a bar, with the aim of revisiting the issue of whether bars affect the radial metal distribution in spirals. In this first paper of a series of two, we present the galaxy and the H ii region samples. The methodology is homogeneous for the whole data sample and includes the derivation of H ii region chemical abundances, structural parameters of bars and discs, galactocentric distances, and radial abundance profiles. We have obtained O/H and N/O abundance ratios from the Te-based (direct) method for a subsample of 610 regions, and from a variety of strong-line methods for the whole H ii region sample. The strong-line methods have been evaluated in relation to the Te-based one from both a comparison of the derived O/H and N/O abundances for individual H ii regions and a comparison of the abundance gradients derived from both methodologies. The median value and the standard deviation of the gradient distributions depend on the abundance method, and those based on the O3N2 indicator tend to flatten the steepest profiles, reducing the range of observed gradients. A detailed analysis and discussion of the derived O/H and N/O radial abundance gradients and y-intercepts for barred and unbarred galaxies is presented in the companion Paper II. The whole H ii region catalogue including emission-line fluxes, positions, and derived abundances is made publicly available on the CDS VizieR facility, together with the radial abundance gradients for all galaxies. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. ; We kindly thank all the authors who have previously published the HII data that form the basis for this work, and Simon Verley for his invaluable help with PYTHON. We also acknowledge the anonymous referee for his/her suggestions that improved the clarity of themanuscript. We thankCalar Alto Observatory for the allocation of director's discretionary time to this programme. AZ, EF, and IP acknowledge support from the Spanish 'Ministerio de Economia, Industria y Competitividad' (MINECO) and from the European Regional Development Fund (FEDER) via grant AYA2017-84897P, and from the Junta de Andalucia (Spain) local government through the FQM-108 project. EPM acknowledges funding from the Spanish MINECO project Estallidos 6 AYA2016-79724-C4 and from the Severo Ochoa excellence programme (SEV-20170709). This research made use of Astropy,15 a community-developed core PYTHON package for Astronomy (Astropy Collaboration 2013; Astropy Collaboration 2018); Matplotlib (Hunter 2007); APLpy, an open-source plotting package for PYTHON (Robitaille & Bressert 2012); NumPy (van der Walt et al. 2011) and seaborn (DOI:10.5281/zenodo.1313201). We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr).This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI:10.26093/cds/vizier). The original description of the VizieR service was published in 2000, A&AS 143, 23. This research has made use of the NASA/IPAC Extragalactic Database (NED) that is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. ; Peer reviewed

We present here the second part of a project that aims at solving the controversy regarding the issue of the bar effect on the radial distribution of metals in the gas-phase of spiral galaxies. In Paper I, we presented a compilation of more than 2800 H ii regions belonging to 51 nearby galaxies for which we derived chemical abundances and radial abundance profiles from a homogeneous methodology. In this paper, we analyse the derived gas-phase radial abundance profiles of 12+log (O/H) and log (N/O), for barred and unbarred galaxies separately, and find that the differences in slope between barred and unbarred galaxies depend on galaxy luminosity. This is due to a different dependence of the abundance gradients (in dex kpc-1) on luminosity for the two types of galaxies: in the galaxy sample under consideration the gradients appear to be considerably shallower for strongly barred galaxies in the whole luminosity range, while profile slopes for unbarred galaxies become steeper with decreasing luminosity. Therefore, we only detect differences in slope for the lower luminosity (lower mass) galaxies (MB-19.5 or M∗ 1010.4 M). We discuss the results in terms of the disc evolution and radial mixing induced by bars and spiral arms. Our results reconcile previous discrepant findings that were biased by the luminosity (mass) distribution of the sample galaxies and possibly by the abundance diagnostics employed. © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. ; We acknowledge Simon Diaz-Garcia for useful discussions. We thank Calar Alto Observatory for allocation of director's discretionary time to this programme. We also thank the anonymous referee for his/her suggestions that improved the clarity of the manuscript. AZ, EF, and IP acknowledge support from the Spanish 'Ministerio de Economia, Industria y Competitividad' (MINECO) and from the European Regional Development Fund (FEDER) via grant AYA201784897-P, and from the Junta de Andaluc ' ia (Spain) local government through the FQM-108 project. EPM acknowledges funding from the Spanish MINECO project Estallidos 6 AYA2016-79724-C4 and from the Severo Ochoa excellence program (SEV-2017-0709). This research made use ofAstropy (http://www.astropy.org) a communitydeveloped core PYTHON package for ASTRONOMY (Astropy Collaboration 2013, 2018); MATPLOTLIB (Hunter 2007); and NUMPY (van der Walt et al. 2011). ; Peer reviewed

Spiral arms are the most singular features in disc galaxies. These structures can exhibit different patterns, namely grand design and flocculent arms, with easily distinguishable characteristics. However, their origin and the mechanisms shaping them are unclear. The overall role of spirals in the chemical evolution of disc galaxies is another unsolved question. In particular, it has not been fully explored if the H ii regions of spiral arms present different properties from those located in the interarm regions. Here we analyse the radial oxygen abundance gradient of the arm and interarm star forming regions of 63 face-on spiral galaxies using CALIFA Integral Field Spectroscopy data. We focus the analysis on three characteristic parameters of the profile: slope, zero-point, and scatter. The sample is morphologically separated into flocculent versus grand design spirals and barred versus unbarred galaxies. We find subtle but statistically significant differences betweenthe arm and interarm distributions for flocculent galaxies, suggesting that the mechanisms generating the spiral structure in these galaxies may be different to those producing grand design systems, for which no significant differences are found. We also find small differences in barred galaxies, not observed in unbarred systems, hinting that bars may affect the chemical distribution of these galaxies but not strongly enough as to be reflected in the overall abundance distribution. In light of these results, we propose bars and flocculent structure as two distinct mechanisms inducing differences in the abundance distribution between arm and interarm star forming regions.© ESO, 2017. ; We acknowledge financial support from the Spanish Ministerio de Economia y Competitividad (MINECO) via grants AYA2012-31935 and AYA2014-53506-P, and from the >Junta de Andalucia> local government through the FQM-108 project. We also acknowledge support from the ConaCyt funding program 180125 and DGAPA IA100815. V.P.D. is supported by STFC Consolidated grant #ST/M000877/1. V.P.D. acknowledges being a part of the network supported by the COST Action TD1403 >Big Data Era in Sky and Earth Observation>. L.G. was supported in part by the US National Science Foundation under Grant AST-1311862. R.A.M. acknowledges support from the Swiss National Science Foundation. J.M.A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild) and MINECO through the grant AYA2013-43188-P. I.M. acknowledges support from the Junta de Andalucia through project TIC114, and the MINECO through projects AYA2013-42227-P and AYA2016-76682C3-1-P. Y.A. is financially supported by the Ramon y Cajal programme (contract RyC-2011-09461) and project AYA2016-79724-C4-1-P from the Spanish MINECO, as well as the exchange programme SELGIFS FP7-PEOPLE-2013-IRSES-612701 funded by the EU. R.M.G.D. acknowledges support from the Spanish grant AYA2010-15081, and from the >Junta de Andalucia> FQ1580 project. ; Peer Reviewed

Astronomy & Astrophysics 587 (2016): A70 reproduced with permission from Astronomy & Astrophysics ; We measured the gas abundance profiles in a sample of 122 face-on spiral galaxies observed by the CALIFA survey and included all spaxels whose line emission was consistent with star formation. This type of analysis allowed us to improve the statistics with respect to previous studies, and to properly estimate the oxygen distribution across the entire disc to a distance of up to 3-4 disc effective radii (re). We confirm the results obtained from classical H ii region analysis. In addition to the general negative gradient, an outer flattening can be observed in the oxygen abundance radial profile. An inner drop is also found in some cases. There is a common abundance gradient between 0.5 and 2.0 re of αO/H =-0.075 dex/re with a scatter of σ = 0.016 dex/re when normalising the distances to the disc effective radius. By performing a set of Kolmogorov-Smirnov tests, we determined that this slope is independent of other galaxy properties, such as morphology, absolute magnitude, and the presence or absence of bars. In particular, barred galaxies do not seem to display shallower gradients, as predicted by numerical simulations. Interestingly, we find that most of thegalaxies in the sample with reliable oxygen abundance values beyond ~2 effective radii (57 galaxies) present a flattening of the abundance gradient in these outer regions. This flattening is not associated with any morphological feature, which suggests that it is a common property of disc galaxies. Finally, we detect a drop or truncation of the abundance in the inner regions of 27 galaxies in the sample; this is only visible for the most massive galaxies ; We acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) via grant AYA2012-31935, and from the "Junta de Andalucía" local government through the FQM-108 project. We also acknowledge support to the ConaCyt funding program 180125. Y.A. acknowledges fi- nantial support from the Ramón y Cajal programme (RyC-2011-09461). Y.A. and A.I.D. acknowledge support from the project AYA2013-47742-C4-3-P from the Spanish MINECO, as well as the "Study of Emission-Line Galaxies with Integral-Field Spectroscopy" (SELGIFS) programme, funded by the EU (FP7- PEOPLE-2013-IRSES-612701). 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. LG acknowledges support by CONICYT through FONDECYT grant 3140566. R.M.G.D. acknowledges support from the Spanish grant AYA2014-57490-P, and from the "Junta de Andalucía" P12-FQM2828 project. RAM thanks the Spanish program of International Campus of Excellence Moncloa (CEI). IM and A.d.O. acknowledge support from the Spanish MINECO grant AYA2013-42227P. JMA acknowledges support from the European Research Council Starting Grant (SEDmorph, P.I. V. Wild). Support for MM has been provided by DGICYT grant AYA2013-47742-C4-4-P. PSB acknowledges support from the Ramón y Cajal programme, grant ATA2010-21322-C03-02 from the Spanish MINECO. CJW acknowledges support through the Marie Curie Career Grant Integration 303912

We measured the gas abundance profiles in a sample of 122 face-on spiral galaxies observed by the CALIFA survey and included all spaxels whose line emission was consistent with star formation. This type of analysis allowed us to improve the statistics with respect to previous studies, and to properly estimate the oxygen distribution across the entire disc to a distance of up to 3-4 disc effective radii (r). We confirm the results obtained from classical H ii region analysis. In addition to the general negative gradient, an outer flattening can be observed in the oxygen abundance radial profile. An inner drop is also found in some cases. There is a common abundance gradient between 0.5 and 2.0 r of α =-0.075 dex/r with a scatter of σ = 0.016 dex/r when normalising the distances to the disc effective radius. By performing a set of Kolmogorov-Smirnov tests, we determined that this slope is independent of other galaxy properties, such as morphology, absolute magnitude, and the presence or absence of bars. In particular, barred galaxies do not seem to display shallower gradients, as predicted by numerical simulations. Interestingly, we find that most of thegalaxies in the sample with reliable oxygen abundance values beyond ~2 effective radii (57 galaxies) present a flattening of the abundance gradient in these outer regions. This flattening is not associated with any morphological feature, which suggests that it is a common property of disc galaxies. Finally, we detect a drop or truncation of the abundance in the inner regions of 27 galaxies in the sample; this is only visible for the most massive galaxies. ; We acknowledge financial support from the Spanish Ministerio de Economia y Competitividad (MINECO) via grant AYA2012-31935, and from the >Junta de Andalucia> local government through the FQM-108 project. We also acknowledge support to the ConaCyt funding program 180125. Y.A. acknowledges finantial support from the Ramon y Cajal programme (RyC-2011-09461). Y.A. and A.I.D. acknowledge support from the project AYA2013-47742-C4-3-P from the Spanish MINECO, as well as the >Study of Emission-Line Galaxies with Integral-Field Spectroscopy> (SELGIFS) programme, funded by the EU (FP7-PEOPLE-2013-IRSES-612701). 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. LG acknowledges support by CONICYT through FONDECYT grant 3140566. R.M.G.D. acknowledges support from the Spanish grant AYA2014-57490-P, and from the >Junta de Andalucia> P12-FQM2828 project. RAM thanks the Spanish program of International Campus of Excellence Moncloa (CEI). IM and A.d.O. acknowledge support from the Spanish MINECO grant AYA2013-42227P. JMA acknowledges support from the European Research Council Starting Grant (SEDmorph, P.I. V. Wild). Support for MM has been provided by DGICYT grant AYA2013-47742-C4-4-P. PSB acknowledges support from the Ramon y Cajal programme, grant ATA2010-21322-C03-02 from the Spanish MINECO. CJW acknowledges support through the Marie Curie Career Grant Integration 303912. ; Peer Reviewed