Fossil Groups Origins III. The relation between optical and X-ray luminosities

This study is part of the FOssil Groups Origin (FOGO) project which aims at carrying out a systematic and multiwavelength study of a large sample of fossil systems. Here we focus on the relation between the optical luminosity (Lopt) and X-ray luminosity (Lx). Out of a sample of 28 candidate fossil systems, we consider a sample of 12 systems whose fossil classification has been confirmed by a companion study. They are compared with the complementary sample of 16 systems whose fossil nature is not confirmed and with a subsample of 102 galaxy systems from the RASS-SDSS galaxy cluster survey. Fossil and normal systems span the same redshift range 0<z<0.5 and have the same Lx distribution. For each fossil system, the Lx in the 0.1-2.4 keV band is computed using data from the ROSAT All Sky Survey. For each fossil and normal system we homogeneously compute Lopt in the r-band within the characteristic cluster radius, using data from the SDSS DR7. We sample the Lx-Lopt relation over two orders of magnitude in Lx. Our analysis shows that fossil systems are not statistically distinguishable from the normal systems both through the 2D KS test and the fit of the Lx-Lopt relation. The optical luminosity of the galaxy system does strongly correlate with the X-ray luminosity of the hot gas component, independently of whether the system is fossil or not. We conclude that our results are consistent with the classical "merging scenario" of the brightest galaxy formed via merger/cannibalism of other group galaxies, with conservation of the optical light. We find no evidence for a peculiar state of the hot intracluster medium.Comment: A&A, 12 pages, 4 figures, 3 tables, typos corr. and paper re-numbe

Methodology for Pumping Station Design Based on Analytic Hierarchy Process (AHP)

[EN] Pumping station (PS) designs in water networks basically contemplate technical and economic aspects. Technical aspects could be related to the number of pumps in PS and the operational modes of PS. Meanwhile, economic aspects could be related to all the costs that intervene in a PS design, such as investment, operational and maintenance costs. In general, water network designs are usually focused on optimizing operational costs or investment costs, However, some subjective technical aspects have not been approached, such as determining the most suitable pump model, the most suitable number of pumps and the complexity of control system operation in a PS design. Therefore, the present work aims to select the most suitable pump model and determine the prior-ities that technical and economic factors could have in a PS design by a multi-criteria analysis, such as an analytic hierarchy process (AHP). The proposed work will contemplate two main criteria, and every criterion will be integrated by sub-criteria to design a PS. In this way, technical factors (number of pumps and complexity of the operating system) and economic factors (investment, operational and maintenance costs) will be considered for a PS design. The proposed methodology consists of realizing surveys to a different group of experts that determines the importance of one criterion over each other criterion in a PS design through pairwise comparisons. Finally, this methodology will provide importance weight for the criteria and sub-criteria on the PS. Besides, this work will perform a rating of the considered alternatives of pump models in every case study, evaluating quantitatively every alternative with every criterion in the PS design. The main objective of this work will select the most adequate pump model according to the obtained rating, considering technical and economic aspects in every case study.This research was funded by the Program Fondecyt Regular, grant number 1210410.Briceño-León, CX.; Sanchez-Ferrer, DS.; Iglesias Rey, PL.; Martínez-Solano, FJ.; Mora-Melia, D. (2021). Methodology for Pumping Station Design Based on Analytic Hierarchy Process (AHP). Water. 13(20):1-35. https://doi.org/10.3390/w13202886S135132

Fossil group origins V. The dependence of the luminosity function on the magnitude gap

In nature we observe galaxy aggregations that span a wide range of magnitude gaps between the two first-ranked galaxies of a system ($\Delta m_{12}$). There are systems with gaps close to zero (e.g., the Coma cluster), and at the other extreme of the distribution, the largest gaps are found among the so-called fossil systems. Fossil and non-fossil systems could have different galaxy populations that should be reflected in their luminosity functions. In this work we study, for the first time, the dependence of the luminosity function parameters on $\Delta m_{12}$ using data obtained by the fossil group origins (FOGO) project. We constructed a hybrid luminosity function for 102 groups and clusters at $z \le 0.25$. We stacked all the individual luminosity functions, dividing them into bins of $\Delta m_{12}$, and studied their best-fit Schechter parameters. We additionally computed a relative luminosity function, expressed as a function of the central galaxy luminosity, which boosts our capacity to detect differences, especially at the bright end. We find trends as a function of $\Delta m_{12}$ at both the bright and faint ends of the luminosity function. In particular, at the bright end, the larger the magnitude gap, the fainter the characteristic magnitude $M^\ast$. We also find differences at the faint end. In this region, the larger the gap, the flatter the faint-end slope $\alpha$. The differences found at the bright end support a dissipationless, dynamical friction-driven merging model for the growth of the central galaxy in group- and cluster-sized halos. The differences in the faint end cannot be explained by this mechanism. Other processes, such as enhanced tidal disruption due to early infall and/or prevalence of eccentric orbits, may play a role. However, a larger sample of systems with $\Delta m_{12} > 1.5$ is needed to establish the differences at the faint end.Comment: 11 pages, 10 figures, accepted for publication in A&

Desarrollo de un servicio experimental de teledetección en los riegos del Porma (León) para el cálculo ajustado de necesidades hídricas y mejora en la gestión del regadío

El proyecto de innovación tecnológica OPTIREG Eficiencia Hídrica, impulsado por el Grupo Tragsa, tiene entre sus objetivos principales introducir el uso de la teledetección, como tecnología de apoyo a la gestión hídrica. Para ello se está desarrollando un servicio web gis experimental que servirá de repositorio único de imágenes y de sus productos derivados y que facilitará, tanto a los regantes, como a los gestores del riego, el seguimiento de los cultivos y de sus necesidades hídricas. Diversos estudios científicos han demostrado la buena relación lineal existente entre el índice de vegetación normalizado (NDVI), derivado de las imágenes de satélite, y el coeficiente de cultivo, Kc (Torres, 2010), utilizado en el cálculo de la evapotranspiración y las necesidades hídricas. Una primera evaluación de los resultados obtenidos en la campaña 2015 para los principales cultivos en regadío en la zona de estudio del Porma (León), indica que el Kc calculado a partir del NDVI, se ajusta mejor que el de FAO. Por ello, se considera un sistema muy válido como referencia para ajustar no sólo la cantidad de agua, sino también para determinar el momento más adecuado de riego, que redundará en una mayor eficiencia hídrica

Imprints of galaxy evolution on H ii regions Memory of the past uncovered by the CALIFA survey

H ii regions in galaxies are the sites of star formation and thus particular places to understand the build-up of stellar mass in the universe. The line ratios of this ionized gas are frequently used to characterize the ionization conditions. We use the Hii regions catalogue from the CALIFA survey (~5000 H ii regions), to explore their distribution across the classical [OIII]/Hbeta vs. [NII]/Halpha diagnostic diagram, and how it depends on the oxygen abundance, ionization parameter, electron density, and dust attenuation. We compared the line ratios with predictions from photoionization models. Finally, we explore the dependences on the properties of the host galaxies, the location within those galaxies and the properties of the underlying stellar population. We found that the location within the BPT diagrams is not totally predicted by photoionization models. Indeed, it depends on the properties of the host galaxies, their galactocentric distances and the properties of the underlying stellar population. These results indicate that although H ii regions are short lived events, they are affected by the total underlying stellar population. One may say that H ii regions keep a memory of the stellar evolution and chemical enrichment that have left an imprint on the both the ionizing stellar population and the ionized gasComment: 18 pages, 8 figures, accepted for publishing in A&

Ionized gas kinematics of galaxies in the CALIFA survey I: Velocity fields, kinematic parameters of the dominant component, and presence of kinematically distinct gaseous systems

This work provides an overall characterization of the kinematic behavior of the ionized gas of the galaxies included in the Calar Alto Legacy Integral field Area (CALIFA), offering kinematic clues to potential users of this survey for including kinematical criteria for specific studies. From the first 200 galaxies observed by CALIFA, we present the 2D kinematic view of the 177 galaxies satisfying a gas detection threshold. After removing the stellar contribution, we used the cross-correlation technique to obtain the radial velocity of the dominant gaseous component. The main kinematic parameters were directly derived from the radial velocities with no assumptions on the internal motions. Evidence of the presence of several gaseous components with different kinematics were detected by using [OIII] profiles. Most objects in the sample show regular velocity fields, although the ionized-gas kinematics are rarely consistent with simple coplanar circular motions. 35% of the objects present evidence of a displacement between the photometric and kinematic centers larger than the original spaxel radii. Only 17% of the objects in the sample exhibit kinematic lopsidedness when comparing receding and approaching sides of the velocity fields, but most of them are interacting galaxies exhibiting nuclear activity. Early-type galaxies in the sample present clear photometric-kinematic misaligments. There is evidence of asymmetries in the emission line profiles suggesting the presence of kinematically distinct gaseous components at different distances from the nucleus. This work constitutes the first determination of the ionized gas kinematics of the galaxies observed in the CALIFA survey. The derived velocity fields, the reported kinematic peculiarities and the identification of the presence of several gaseous components might be used as additional criteria for selecting galaxies for specific studies.Comment: 38 pages, 16 figures, 4 tables. Paper accepted for publication in A&