J-PLUS : measuring Hα emission line fluxes in the nearby universe

n this paper we aim to validate a methodology designed to obtain Hα emission line fluxes from J-PLUS photometric data. J-PLUS is a multi narrow-band filter survey carried out with the 2 deg2 field of view T80Cam camera, mounted on the JAST/T80 telescope in the OAJ, Teruel, Spain. The information of the twelve J-PLUS bands, including the J0660 narrow-band filter located at rest-frame Hα, is used over the first 42 deg2 observed to retrieve de-reddened and [NII] decontaminated Hα emission line fluxes of 46 star-forming regions with previous SDSS and/or CALIFA spectroscopic information. The agreement between the J-PLUS Hα fluxes and those obtained with spectroscopic data is remarkable, finding a median comparison ratio with a scatter of R = F J−PLUS Hα /F spec Hα = 1.05 ± 0.25. This demonstrates that it is possible to retrieve reliable Hα emission line fluxes from J-PLUS photometric data. With an expected area of thousands of square degrees upon completion, the J-PLUS dataset will allow the study of several star formation science cases in the nearby universe, as the spatially resolved star formation rate of nearby galaxies at z  ≤  0.015, and how it is influenced by the environment, morphology, stellar mass, and nuclear activity. As an illustrative example, the close pair of interacting galaxies NGC 3994 and NGC 3995 is analysed, finding an enhancement of the star formation rate not only in the centre, but also in outer parts of the disk of NGC 3994

Polish device for FOCCoS/PFS slit system

The Fiber Optical Cable and Connector System, FOCCoS, for the Prime Focus Spectrograph, PFS, is responsible for transporting light from the Subaru Telescope focal plane to a set of four spectrographs. Each spectrograph will be fed by a convex curved slit with 616 optical fibers organized in a linear arrangement. The slit frontal surface is covered with a special dark composite, made with refractory oxide, which is able to sustain its properties with minimum quantities of abrasives during the polishing process; this stability is obtained This stability is obtained by the detachment of the refractory oxide nanoparticles, which then gently reinforce gently the polishing process and increase its the efficiency. The surface roughness measured in several samples after high performance polishing was about 0.01 microns. Furthermore, the time for obtaining a polished surface with this quality is about 10 times less than the time required for polishing a brass, glass or ceramic surface of the same size. In this paper, we describe the procedure developed for high quality polishing of this type of slit. The cylindrical polishing described here, uses cylindrical concave metal bases on which glass paper is based. The polishing process consists to use grid sequences of 30 microns, 12 microns, 9 microns, 5 microns, 3 microns, 1 micron and, finally, a colloidal silica on a chemical cloth. To obtain the maximum throughput, the surface of the fibers should be polished in such a way that they are optically flat and free from scratches. The optical fibers are inspected with a microscope at all stages of the polishing process to ensure high quality. The efficiency of the process may be improved by using a cylindrical concave composite base as a substrate suitable for diamond liquid solutions. Despite this process being completely by hand, the final result shows a very high quality

J-PLUS : a catalogue of globular cluster candidates around the M 81/M 82/NGC 3077 triplet of galaxies

Globular clusters (GCs) are proxies of the formation assemblies of their host galaxies. However, few studies exist targeting GC systems of spiral galaxies up to several effective radii. Through 12-band Javalambre Photometric Local Universe Survey (J-PLUS) imaging, we study the point sources around the M 81/M 82/NGC 3077 triplet in search of new GC candidates. We develop a tailored classification scheme to search for GC candidates based on their similarity to known GCs via a principal component analysis projection. Our method accounts for missing data and photometric errors. We report 642 new GC candidates in a region of 3.5 deg2 around the triplet, ranked according to their Gaia astrometric proper motions when available. We find tantalizing evidence for an overdensity of GC candidate sources forming a bridge connecting M 81 and M 82. Finally, the spatial distribution of the GC candidates (g − i) colours is consistent with halo/intra-cluster GCs, i.e. it gets bluer as they get further from the closest galaxy in the field. We further employ a regression-tree-based model to estimate the metallicity distribution of the GC candidates based on their J-PLUS bands. The metallicity distribution of the sample candidates is broad and displays a bump towards the metal-rich end. Our list increases the population of GC candidates around the triplet by threefold, stresses the usefulness of multiband surveys in finding these objects, and provides a testbed for further studies analysing their spatial distribution around nearby (spirals) galaxies

The distribution of stellar populations within galaxies

The study of stellar populations in galaxies is particularly interesting, since they are a fossil record of several physical processes associated with the formation and evolution of galaxies. In this work we present the first results of our approach to study the spatial distribution of stellar populations inside galaxies. We are using ugriz magnitudes and principal component analysis (PCA) to obtain pixel-by-pixel proxies of the stellar populations and their distributions inside each galaxy. The distribution of these populations are then investigated with a variety of statistical tools, including Gini Indices and the Euler-Poincaré characteristic. Our approach aims to be a step forward with respect to the conventional profile fitting, allowing to obtain quantitative estimates on how the different stellar populations are distributed within a galaxy, bringing hints on how galaxies grow and evolve. The pixel-by-pixel analysis of a small sample of 15 galaxies of different types show that the stellar populations tend to evolve from inside to out in spiral and late spiral galaxies, while elliptical galaxies seem to have young stellar populations in the center. This first results show that this approach is effective and will be explored and improve in future works.Resumo publicado no periódico: Revista Mexicana de Astronomía y Astrofísica. Serie de Conferencias, V. 44, P. 182-183, 2014

A data-driven approach to the emission line properties of star-forming galaxies

We present a quantitative analysis of the correlations\ud between the equivalent widths of optical emission\ud lines for a sample of more than 70,000 starforming\ud galaxies with high S/N SDSS spectra and\ud with spectral synthesis performed with the Starlight\ud software. We show, using statistical tools such as the\ud distance correlation and maximal information correlation,\ud that there are indeed strong correlations between\ud the most prominent emission lines usually detected\ud in the optical region of galaxy spectra. We\ud have done, also, a Principal Component Analysis\ud (PCA) of the synthesized continuum spectra and\ud used up to 10 components to train an artificial neural\ud network to estimate the equivalent widths of the\ud emission lines, with excellent results, demonstrating\ud that there is a strong correlation between the continuum\ud and equivalent widths. The same analysis\ud was performed with the symbolic regression software\ud Eureqa, which provided functional relations between\ud the four principal components and the equivalent\ud widths, with an accuracy between 0.12 and 0.24 dex\ud for different emission lines. The main motivation behind\ud this work is to produce realistic spectra for tests of data reduction pipelines of the new generation of\ud galaxy surveys, like J-PAS and PFS/SuMIRe.Resumo publicado no periódico: Revista Mexicana de Astronomía y Astrofísica. Serie de Conferencias, v. 44, p. 187, 2014

The relation between the spectral synthesis of galaxies in the visible region and their UV emission

The STARLIGHT Project has analyzed almost a\ud million spectra extracted from the Sloan Digital\ud Sky Survey (SDSS) by using the empirical spectral\ud synthesis approach described by Cid Fernandes et\ud al.(2005). Spectral synthesis consists on the optical\ud spectrum fitting by using simple stellar population\ud libraries, such as Bruzual & Charlot (2003). It also\ud considers the reddening caused by dust and the velocity\ud dispersion due to the motion of the stars within\ud the galaxy. Since the model that best fits the optical\ud region can also be extended to the ultraviolet,\ud we compare our predictions to the UV photometry\ud of the same galaxies measured by the GALEX satellite,\ud studying the systematics and nature of the differences.\ud In this current presentation, we show the\ud upcoming challenges in order to accomplish this investigation.\ud The main motivation of this study is to\ud obtain realistic spectral models from the UV to the\ud optical regions for the study of high redshift galaxies.Resumo publicado no periódico: Revista Mexicana de Astronomía y Astrofísica. Serie de Conferencias, v. 44, p. 175, 2014

J-PLUS : two-dimensional analysis of the stellar population in NGC 5473 and NGC 5485

Context. The spatial variations of stellar population properties within a galaxy are intimately related to their formation process. Therefore, spatially resolved studies of galaxies are essential to uncover their formation and assembly. Although the arrival of integral field unit (IFU) surveys has brought a significant breakthrough in the field, recent techniques that combine photometric multifilter surveys with spectral fitting diagnostics have opened a new, relatively low-cost way to disentangle the stellar population of spatially resolved galaxies compared to IFU surveys. Aims. The Javalambre Photometric Local Universe Survey (J-PLUS) is a dedicated multifilter designed to observed ∼8500 deg2 of the northern sky using 12 narrowband, intermediate-band, and broadband filters in the optical range. In this study, we test the potential of the multifilter observation carried out with J-PLUS to investigate the properties of spatially resolved nearby galaxies. Methods. We present detailed 2D maps of stellar population properties, i.e., age, metallicity, extinction, and stellar mass surface density, for two early-type galaxies observed in the J-PLUS and CALIFA surveys. These galaxies are NGC 5473 and NGC 5485. Radial structures are also compared and luminosity- and mass-weighted profiles are derived. We use MUFFIT to process the J-PLUS photometric multifilter observations, and STARLIGHT and STECKMAP to analyze IFU CALIFA data. Results. We demonstrate the scientific potential of J-PLUS/MUFFIT to explore the spatially resolved stellar populations of local galaxies. We find significant discrepancies between the results from the various analysis methods. While radial stellar population gradients obtained with J-PLUS/MUFFIT and the IFU technique CALIFA/STECKMAP are more in agreement, radial stellar population gradients largely differ when CALIFA/STARLIGHT methodology is used. A comparison of the absolute values reveals the existence of intrinsic systematic differences. Age and metallicity radial profiles derived from J-PLUS/MUFFIT are very similar when luminosity- or mass-weighted properties are used, suggesting that the contribution of a younger component is small and the star formation history of these early-type galaxies are well represented by mainly an old single stellar population component. Conclusions. We present the potential of J-PLUS to explore the unresolved stellar populations of spatially extended local galaxies. A comparison between the three methodologies reveals some discrepancies suggesting that the specific characteristics of each method causes important differences. We conclude that the ages, metallicities, and extinction derived for individual galaxies not only depend on the chosen models but also depend on the method used. Future work is required to evaluate in detail the origin of these differences and to quantify the impact that different fitting routines have on the derived stellar population properties

J-PLUS : two-dimensional analysis of the stellar population in NGC 5473 and NGC 5485

Context. The spatial variations of stellar population properties within a galaxy are intimately related to their formation process. Therefore, spatially resolved studies of galaxies are essential to uncover their formation and assembly. Although the arrival of integral field unit (IFU) surveys has brought a significant breakthrough in the field, recent techniques that combine photometric multifilter surveys with spectral fitting diagnostics have opened a new, relatively low-cost way to disentangle the stellar population of spatially resolved galaxies compared to IFU surveys. Aims. The Javalambre Photometric Local Universe Survey (J-PLUS) is a dedicated multifilter designed to observed ∼8500 deg2 of the northern sky using 12 narrowband, intermediate-band, and broadband filters in the optical range. In this study, we test the potential of the multifilter observation carried out with J-PLUS to investigate the properties of spatially resolved nearby galaxies. Methods. We present detailed 2D maps of stellar population properties, i.e., age, metallicity, extinction, and stellar mass surface density, for two early-type galaxies observed in the J-PLUS and CALIFA surveys. These galaxies are NGC 5473 and NGC 5485. Radial structures are also compared and luminosity- and mass-weighted profiles are derived. We use MUFFIT to process the J-PLUS photometric multifilter observations, and STARLIGHT and STECKMAP to analyze IFU CALIFA data. Results. We demonstrate the scientific potential of J-PLUS/MUFFIT to explore the spatially resolved stellar populations of local galaxies. We find significant discrepancies between the results from the various analysis methods. While radial stellar population gradients obtained with J-PLUS/MUFFIT and the IFU technique CALIFA/STECKMAP are more in agreement, radial stellar population gradients largely differ when CALIFA/STARLIGHT methodology is used. A comparison of the absolute values reveals the existence of intrinsic systematic differences. Age and metallicity radial profiles derived from J-PLUS/MUFFIT are very similar when luminosity- or mass-weighted properties are used, suggesting that the contribution of a younger component is small and the star formation history of these early-type galaxies are well represented by mainly an old single stellar population component. Conclusions. We present the potential of J-PLUS to explore the unresolved stellar populations of spatially extended local galaxies. A comparison between the three methodologies reveals some discrepancies suggesting that the specific characteristics of each method causes important differences. We conclude that the ages, metallicities, and extinction derived for individual galaxies not only depend on the chosen models but also depend on the method used. Future work is required to evaluate in detail the origin of these differences and to quantify the impact that different fitting routines have on the derived stellar population properties

J-PLUS : measuring Hα emission line fluxes in the nearby universe

n this paper we aim to validate a methodology designed to obtain Hα emission line fluxes from J-PLUS photometric data. J-PLUS is a multi narrow-band filter survey carried out with the 2 deg2 field of view T80Cam camera, mounted on the JAST/T80 telescope in the OAJ, Teruel, Spain. The information of the twelve J-PLUS bands, including the J0660 narrow-band filter located at rest-frame Hα, is used over the first 42 deg2 observed to retrieve de-reddened and [NII] decontaminated Hα emission line fluxes of 46 star-forming regions with previous SDSS and/or CALIFA spectroscopic information. The agreement between the J-PLUS Hα fluxes and those obtained with spectroscopic data is remarkable, finding a median comparison ratio with a scatter of R = F J−PLUS Hα /F spec Hα = 1.05 ± 0.25. This demonstrates that it is possible to retrieve reliable Hα emission line fluxes from J-PLUS photometric data. With an expected area of thousands of square degrees upon completion, the J-PLUS dataset will allow the study of several star formation science cases in the nearby universe, as the spatially resolved star formation rate of nearby galaxies at z  ≤  0.015, and how it is influenced by the environment, morphology, stellar mass, and nuclear activity. As an illustrative example, the close pair of interacting galaxies NGC 3994 and NGC 3995 is analysed, finding an enhancement of the star formation rate not only in the centre, but also in outer parts of the disk of NGC 3994

馬建忠馬氏文通之研究

本論文研究《馬氏文通》，其研究之重點在於探討馬建忠《馬氏文通》的語法理論，以及《馬氏文通》對后來語法研究的影響。本論文凡六章。第一章緒論，分為兩節。第一節略述筆者撰述本論文之研究動機、研究目的及研究方法。第二節略述《馬氏文通》以前的語法研究概況。第二章為《馬氏文通》的概說，敘述《馬氏文通》的作者、撰述動機、體例和用例，并且分析馬氏所用的主要語法術語，以作為研究《馬氏文通》的基礎。第三章論《馬氏文通》的詞法理論，分為實字和虛字兩節來探討《馬氏文通》對名字、代字、動字、靜字、象字、介字、連字、助字、歎字各詞類的界說、分類、用法及用例。第四章論《馬氏文通》的句法理論。第五節以起詞、語詞、止詞、轉詞、加詞、司詞句子成分及頓、讀、句為研究對象，探討馬建忠的句法理論。第二節以主次、實次、偏次、正次、前次、同次和平比、差比、極比為研究對象，探討《馬氏文通》的「次」和「比」語法範疇論。第五章論述「馬氏文通」對后來語法研究的影響。主要陳述「馬氏文通」對后來語法術語、詞類體系及分類、各詞類的小分類、句子分析、句子分類和語法範疇研究的影響。第六章為結論。先將本論的內容扼要整理，再論《馬氏文通》在語法理論上的特色，探究《馬氏文通》中國語法文學史上的地位，并予以評價