1,720,993 research outputs found
The SDSS-IV eBOSS: Emission line galaxy catalogues at z ≈ 0.8 and study of systematic errors in the angular clustering
No full textDelubac, Timothée et al.-- Full list of authors: Delubac, T.; Raichoor, A.; Comparat, J.; Jouvel, S.; Kneib, J. -P.; Yèche, C.; Zou, H.; Brownstein, J. R.; Abdalla, F. B.; Dawson, K.; Jullo, E.; Myers, A. D.; Newman, J. A.; Percival, W. J.; Prada, F.; Ross, A. J.; Schneider, D. P.; Zhou, X.; Zhou, Z.; Zhu, G.We present two wide-field catalogues of photometrically selected emission line galaxies (ELGs) at z ≈ 0.8 covering about 2800 degover the south galactic cap. The catalogues were obtained using a Fisher discriminant technique described in a companion paper. The two catalogues differ by the imaging used to define the Fisher discriminant: the first catalogue includes imaging from the Sloan Digital Sky Survey and the Wide-field Infrared Survey Explorer, the second also includes information from the South Galactic Cap U-band Sky Survey. Containing respectively 560 045 and 615 601 objects, they represent the largest ELG catalogues available today and were designed for the ELG programme of the extended Baryon Oscillation Spectroscopic Survey (eBOSS). We study potential sources of systematic variation in the angular distribution of the selected ELGs due to fluctuations of the observational parameters. We model the influence of the observational parameters using a multivariate regression and implement a weighting scheme which allows effective removal of all of the systematic errors induced by the observational parameters. We show that fluctuations in the imaging zero-points of the photometric bands have minor impact on the angular distribution of objects in our catalogues. We compute the angular clustering of both catalogues and show that our weighting procedure effectively removes spurious clustering on large scales. We fit a model to the small-scale angular clustering, showing that the selections have similar biases of 1.35/D(z) and 1.28/D(z). Both catalogues are publicly available. © 2016 The AuthorsTD and JPK acknowledge support from the ERC advanced grant
LIDA. JC acknowledges financial support from MINECO (Spain)
under project number AYA2012-31101. AR acknowledges funding
from the P2IO LabEx (ANR-10-LABX-0038) in the framework ‘Investissements d’ Avenir’ (ANR-11-IDEX-0003-01) managed by the
French National Research Agency (ANR). JC and FP acknowledge
support from the Spanish MICINNs Consolider-Ingenio 2010 Programme under grant MultiDark CSD2009-00064, MINECO Centro
de Excelencia Severo Ochoa Programme under grant SEV- 2012-
0249 and MINECO grant AYA2014-60641-C2-1-P. EJ acknowledges financial support from CNRS/INSU, France.
Funding for SDSS-III has been provided by the Alfred P. Sloan
Foundation, the Participating Institutions, the National Science
Foundation and the US Department of Energy Office of Science.
The SDSS-III website is http://www.sdss3.org/.
SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III
Collaboration including the University of Arizona, the Brazilian
Participation Group, Brookhaven National Laboratory, Carnegie
Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan
State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University,
Ohio State University, Pennsylvania State University, University of
Portsmouth, Princeton University, the Spanish Participation Group,
University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington and Yale University.
Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of
Energy Office of Science and the Participating Institutions. SDSSIV acknowledges support and resources from the Center for HighPerformance Computing at the University of Utah. The SDSS website is www.sdss.org.
SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration
including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian
Center for Astrophysics, Instituto de Astrof´ısica de Canarias, the
Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence
Berkeley National Laboratory, Leibniz Institut fur Astrophysik ¨
Potsdam (AIP), Max-Planck-Institut fur Astronomie (MPIA Hei- ¨
delberg), Max-Planck-Institut fur Astrophysik (MPA Garching), ¨
Max-Planck-Institut fur Extraterrestrische Physik (MPE), National ¨
Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatario ´
Nacional/MCTI, the Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autonoma de M ´ exico, Uni- ´
versity of Arizona, University of Colorado Boulder, University of
Portsmouth, University of Utah, University of Virginia, University
of Washington, University of Wisconsin, Vanderbilt University and
Yale University.
The SCUSS is funded by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences (No. KJCX2-
EW-T06). It is also an international cooperative project between
National Astronomical Observatories, Chinese Academy of Sciences and Steward Observatory, University of Arizona, USA. Technical supports and observational assistances of the Bok telescope
are provided by Steward Observatory. The project is managed by
the National Astronomical Observatory of China and Shanghai Astronomical Observatory.
This publication makes use of data products from the Wide-field
Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, and NEOWISE, which is
a project of the Jet Propulsion Laboratory/California Institute of
Technology. WISE and NEOWISE are funded by the National Aeronautics and Space Administration
Détections des oscillations acoustiques de baryons grâce aux forêts Lyman-α des spectres de quasars de l'expérience BOSS
No full textBaryon acoustic oscillations (BAO) form a standard ruler that can be used to constrain different cosmolo- gical models. This thesis reports the first measurement of the BAO feature in the correlation function of the transmitted flux fraction in the Lyman-α forests of high redshift quasars. This detection uses 89322 quasar spectra measured by the Baryon Oscillation Spectroscopic Survey (BOSS) of the third generation of the Sloan Digital Sky Survey (SDSS-III). Redshift of used quasars belong to the range 2.1 < z < 3.5. A peak in the correlation function is seen at 1.043+0.021−0.020 times the expected BAO peak position for a concordance ΛCDM model. In addition this thesis presents a new method of quasar selection through their variability. This method is applied to the Stripe 82 region where an important number of multi-epoch photometric data is available. On this region it achieves a quasar density of 30 deg−2 to be compared with the 18 deg−2 of usual color selections.Les oscillations acoustiques de baryons (BAO) constituent une règle standard permettant de contraindre les différents modèles cosmologiques. Cette thèse rend compte de la première mesure des BAO dans la fonction de corrélation de la fraction de flux transmise des forêts Lyman-α des quasars à grands décalages spectraux. Cette détection utilise 89322 spectres de quasars mesurés par le Baryon Oscillation Spectroscopic Survey (BOSS) de la troisième génération du Sloan Digital Sky Survey (SDSS-III). Les quasars considérés possèdent des décalages spectraux compris dans l'intervalle 2,1 < z < 3,5. Un pic dans la fonction de corrélation est détecté à 1,043+0,021−0,020 fois la position attendu du pic BAO pour le modèle de concordance ΛCDM. Cette mesure permet de contraindre la distance angulaire DA ainsi que le paramètre de Hubble H à un décalage spectral moyen z = 2,38. Par ailleurs cette thèse présente une nouvelle méthode de sélection des quasars par variabilité. Cette méthode est appliquée à la région du Stripe 82 où un grand nombre de données photométriques multi- époque est disponible. Sur cette région, elle permet d'atteindre une densité d'environ 30 deg−2 quasars contre 18 deg−2 pour les sélections usuelles par couleur
Détections des oscillations acoustiques de baryons grâce aux forêts Lyman-α des spectres de quasars de l'expérience BOSS
No full textBaryon acoustic oscillations (BAO) form a standard ruler that can be used to constrain different cosmolo- gical models. This thesis reports the first measurement of the BAO feature in the correlation function of the transmitted flux fraction in the Lyman-α forests of high redshift quasars. This detection uses 89322 quasar spectra measured by the Baryon Oscillation Spectroscopic Survey (BOSS) of the third generation of the Sloan Digital Sky Survey (SDSS-III). Redshift of used quasars belong to the range 2.1 < z < 3.5. A peak in the correlation function is seen at 1.043+0.021−0.020 times the expected BAO peak position for a concordance ΛCDM model. In addition this thesis presents a new method of quasar selection through their variability. This method is applied to the Stripe 82 region where an important number of multi-epoch photometric data is available. On this region it achieves a quasar density of 30 deg−2 to be compared with the 18 deg−2 of usual color selections.Les oscillations acoustiques de baryons (BAO) constituent une règle standard permettant de contraindre les différents modèles cosmologiques. Cette thèse rend compte de la première mesure des BAO dans la fonction de corrélation de la fraction de flux transmise des forêts Lyman-α des quasars à grands décalages spectraux. Cette détection utilise 89322 spectres de quasars mesurés par le Baryon Oscillation Spectroscopic Survey (BOSS) de la troisième génération du Sloan Digital Sky Survey (SDSS-III). Les quasars considérés possèdent des décalages spectraux compris dans l'intervalle 2,1 < z < 3,5. Un pic dans la fonction de corrélation est détecté à 1,043+0,021−0,020 fois la position attendu du pic BAO pour le modèle de concordance ΛCDM. Cette mesure permet de contraindre la distance angulaire DA ainsi que le paramètre de Hubble H à un décalage spectral moyen z = 2,38. Par ailleurs cette thèse présente une nouvelle méthode de sélection des quasars par variabilité. Cette méthode est appliquée à la région du Stripe 82 où un grand nombre de données photométriques multi- époque est disponible. Sur cette région, elle permet d'atteindre une densité d'environ 30 deg−2 quasars contre 18 deg−2 pour les sélections usuelles par couleur
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Détections des oscillations acoustiques de baryons grâce aux forêts Lyman-a des spectres de quasars de l'expérience BOSS
No full textLes oscillations acoustiques de baryons (BAO) constituent une règle standard permettant de contraindre les différents modèles cosmologiques. Cette thèse rend compte de la première mesure des BAO dans la fonction de corrélation de la fraction de flux transmise des forêts Lyman- S\ alphaS des quasars à grands décalages spectraux. Cette détection utilise 89322 spectres de quasars mesurés par le Baryon Oscillation Spectroscopic Survey (BOSS) de la troisième génération du Sloan Digital Sky Survey (SDSS-I11). Les quasars considérés possèdent des décalages spectraux compris dans l'intervalle S2,1<z<3,5S. Un pic dans la fonction de corrélation est détecté à S1,043^{+0,021}_{-0,020} fois la position attendu du pic BAO pour le modèle de concordance S\Lambda SCDM. Cette mesure permet de contraindre la distance angulaire SD_A S ainsi que le paramètre de Hubble SHS à un décalage spectral moyen z = 2,38 Par ailleurs cette thèse présente une nouvelle méthode de sélection des quasars par variabilité. Cette méthode est appliquée à la région du S\emph{Stripe 82}S où un grand nombre de données photométriques multi-époque est disponible. Sur cette région, elle permet d'atteindre une densité d'environ 30 degS^{-2}S quasars contre 18 degS ^{-2}S pour les sélections usuelles par couleur.Baryon acoustic oscillations (BAO) form a standard ruler that can be used to constrain different cosmological models. This thesis reports the first measurement of the BAO feature in the correlation function of the transmitted flux fraction in the \ Iya-forests of high redshift quasars. This detection uses 89322 quasar spectra measured by the Baryon Oscillation Spectroscopic Survey (BOSS) of the third generation of the Sloan Digital Sky Survey (SDSS-III). Redshift of used quasars belong to the range S2,1<z<3,5S . A peak in the correlation function is seen at S1,043^{+0,021}_{-0,020} times the expected BAO peak position for a concordance S\Lambda CDM model. In addition this thesis presents a new method of quasar selection through their variability. This method is applied to the Stripe 82 region where an important number of multi-epoch photometric data is available. On this region it achieves a quasar density of 30 degS^{-2}S to be compared with the 18 degS ^{-2}S of usual color selections.PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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