A Spectroscopic Study of the Near-IR [SIII] Lines in a Sample of HII Galaxies: chemical abundances

A detailed spectroscopic study, from lambda 3700 A to 1 um, was performed for a sample of 34 HII galaxies in order to derive fundamental parameters for their HII regions and ionizing sources, as well as gaseous metal abundances. All the spectra included the nebular [SIII]9069,9532 A lines, given their importance in the derivation of the S/H abundance and relevant ionization diagnostics. A systematic method was followed to correct the near-IR [SIII] line fluxes for the effects of the atmospheric transmission.A comparative analysis of the predictions of the empirical abundance indicators R23 and S23 has been performed. The relative hardness of their ionizing sources was studied using the eta parameter, and exploring the role played by metallicity. For 22 galaxies of the sample a direct value of te[SIII] was derived, along with their ionic and total S/H abundances. Their ionic and total O/H abundances were derived using direct determinations of te[OIII].For the rest of the objects, the total S/H abundance was derived using S23. The abundance range covered by our sample goes from 1/20 solar up to solar metallicity. The mean S/O ratio derived is log (S/O)=-1.68+/-0.20 dex, 1 sigma below the solar S/O value. The S/O abundance ratio shows no significant trend with O/H over the range of abundance covered in this work, in agreement with previous findings.There is a trend for HII galaxies with lower gaseous metallicity to present harder ionizing spectra. We compared the distribution of the ionic ratios O+/O++ vs. S+/S++ derived for our sample with the predictions of a grid of photoionization models performed for different stellar effective temperatures. This analysis indicates that a large fraction of galaxies in our sample seem to be ionized by extremely hard spectra.Comment: 12 pages, 8 figures, accepted for publication in the A&A, minor gramatical corrections include

Integral field spectroscopy of nitrogen overabundant blue compact dwarf galaxies

We study the spatial distribution of the physical properties and of oxygen and nitrogen abundances in three Blue Compact Dwarf Galaxiess (HS 0128+2832, HS 0837+4717 and Mrk 930) with a reported excess of N/O in order to investigate the nature of this excess and, particularly, if it is associated with Wolf-Rayet (WR) stars We have observed these BCDs by using PMAS integral field spectroscopy in the optical spectral range (3700 - 6900 {\AA}), mapping their physical-chemical properties, using both the direct method and appropriate strong-line methods. We make a statistical analysis of the resulting distributions and we compare them with the integrated properties of the galaxies. Our results indicate that outer parts of the three galaxies are placed on the "AGN-zone" of the [NII]/H{\alpha} vs. [OIII]/H{\beta} diagnostic diagram most likely due to a high N/O combined with the excitation structure in these regions. From the statistical analysis, it is assumed that a certain property can be considered as spatially homogeneous (or uniform) if a normal gaussian function fits its distribution in several regions of the galaxy. Moreover, a disagreement between the integrated properties and the mean values of the distribution usually appears when a gaussian does not fit the corresponding distribution. We find that for Mrk 930, the uniformity is found for all parameters, except for electron density and reddening. The rotation curve together with the H{\alpha} map and UV images, reveal a perturbed morphology and possible interacting processes. The N/O is found to be constant in the three studied objects at spatial scales of the order of several kpc so we conclude that the number of WR stars estimated from spectroscopy is not sufficient to pollute the ISM and to produce the observed N/O excess in these objectsComment: 17 pages, 14 figures, accepted for publication in Astronomy & Astrophysic

Using photoionization models to derive carbon and oxygen gas-phase abundances in the rest UV

We present a new method to derive oxygen and carbon abundances using the ultraviolet (UV) lines emitted by the gas phase ionized by massive stars. The method is based on the comparison of the nebular emission-line ratios with those predicted by a large grid of photoionization models. Given the large dispersion in the O/H–C/O plane, our method first fixes C/O using ratios of appropriate emission lines and, in a second step, calculates O/H and the ionization parameter from carbon lines in the UV. We find abundances totally consistent with those provided by the direct method when we apply this method to a sample of objects with an empirical determination of the electron temperature using optical emission lines. The proposed methodology appears as a powerful tool for systematic studies of nebular abundances in star-forming galaxies at high redshift.EPM acknowledges support from the Spanish MICINN through grants AYA2010-21887-C04-01 and AYA2013-47742-C4-1-P and the Junta de Andalucía for grant EXC/2011 FQM-7058. RA acknowledges the support from the ERC Advanced Grant 695671 ‘QUENCH’ and the FP7 SPACE project ‘ASTRODEEP’ (Ref. No.: 312725), supported by the European Commission

The temperature and ionization structure of the emitting gas in HII galaxies: Implications for the accuracy of abundance determinations

We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the production and calibration of empirical relations between the different line temperatures that should superseed currently used ones based on very simple, and poorly tested, photo-ionization model sequences. As a first step to reach these goals we have obtained simultaneous blue to far red longslit spectra with the William Herschel Telescope (WHT) of three compact HII galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 2 (DR2) spectral catalog using the INAOE Virtual Observatory superserver. Our spectra cover the range from 3200 to 10500 \AA, including the Balmer jump, the [OII]3727,29 \AA lines, the [SIII]9069,9532 \AA doublet as well as various weak auroral lines such as [OIII]4363 \AA and [SIII]6312 \AA. For the three objects we have measured at least four line temperatures: T([OIII]), T([SIII]), T([OII]) and T([SII]) and the Balmer continuum temperature T(Bac). These measurements and a careful and realistic treatment of the observational errors yield total oxygen abundances with accuracies between 5 and 9%. These accuracies are expected to improve as better calibrations based on more precise measurements, both on electron temperatures and densities, are produced. ..

Behavioural indicators of innovators. A search protocol for a systematic literature review

[EN] Introducing greater innovation into the culture and capabilities of organizations worldwide, a requirement of today¿s society,is an issue currently in need of scholarly attention. The present investigation is being undertaken within the context of FINCODA, a European Project involved in the development of new reliable tools for innovation competences assessment. The study aims at devising a search protocol for a systematic review of the literature on behavioral indicators of innovators published from 2000 onwards, indexed in Scopus, Web of Science and Google Scholar. The specific keywords used in the search include the following fields: (1) workplace; (2) innovative behaviour, innovative work behaviour and individual innovation; (3) indicators. A preliminary search with these keywords retrieved 1,350 references. Then, the process of filtering data by title and abstract to meet inclusive and exclusive criteria refined the search. The materials identified are expected to prove useful in the definition of behavioural indicators of innovative people at work. Moreover, they will help in the analysis of the relation of the descriptors found with the innovative indicators of a barometer created within a previous European Project, INCODE, and in the further design of a tool to measure employees¿ innovation.This research has been supported by the Erasmus+ Project FINCODA, Framework for Innovation Competences Development and Assessment_554493-EPP-1-2014-1-FI-EPPKA2-KA (The European Commission support for the production of this publication does not constitute an endorsement of the contents which reflects the views only of th e authors, and the Commission cannot be held responsible for any use which may be made of the information contained therein) and by the Project PIME 2015 - 2016 A/09_Evaluación de los indicadores del comportamiento innovador en el alumno universitario, at th e Universitat Politecnica de Valencia (Spain).Montero Fleta, MB.; Pérez Peñalver, MJ.; Aznar-Mas, LE. (2017). Behavioural indicators of innovators. A search protocol for a systematic literature review. New Trends and Issues Proceedings on Humanities and Social Sciences. 3(1):113-120. https://doi.org/10.18844/gjhss.v3i1.1757S1131203