142 research outputs found
CLASH: Joint Analysis of Strong-Lensing, Weak-Lensing Shear and Magnification Data for 20 Galaxy Clusters
We present a comprehensive analysis of strong-lensing, weak-lensing shear and magnification data for a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19 ⟠z ⟠0.69 selected from Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis combines constraints from 16-band Hubble Space Telescope observations and wide-field multi-color imaging taken primarily with Suprime-Cam on the Subaru Telescope, spanning a wide range of cluster radii (10"â16'). We reconstruct surface mass density profiles of individual clusters from a joint analysis of the full lensing constraints, and determine masses and concentrations for all of the clusters. We find the internal consistency of the ensemble mass calibration to be â€5% ± 6% in the one-halo regime (200â2000 kpc hâ1) compared to the CLASH weak-lensing-only measurements of Umetsu et al. For the X-ray-selected subsample of 16 clusters, we examine the concentrationâmass (câM) relation and its intrinsic scatter using a Bayesian regression approach. Our model yields a mean concentration of c|_z=0.34 =3.95 ± 0.35 at M_(200c) â 14 Ă 10^(14) M_â and an intrinsic scatter of Ï(ln c_(200c) = 0.13 ± 0.06, which is in excellent agreement with Î cold dark matter predictions when the CLASH selection function based on X-ray morphological regularity and the projection effects are taken into account. We also derive an ensemble-averaged surface mass density profile for the X-ray-selected subsample by stacking their individual profiles. The stacked lensing signal is detected at 33Ï significance over the entire radial range â€4000 kpc h^(â1), accounting for the effects of intrinsic profile variations and uncorrelated large-scale structure along the line of sight. The stacked mass profile is well described by a family of density profiles predicted for cuspy dark-matter-dominated halos in gravitational equilibrium, namely, the NavarroâFrenkâWhite (NFW), Einasto, and DARKexp models, whereas the single power-law, cored isothermal and Burkert density profiles are disfavored by the data. We show that cuspy halo models that include the large-scale two-halo term provide improved agreement with the data. For the NFW halo model, we measure a mean concentration of c_(200c) = 3.79_(-0.28)^(+0.30) at M_(200c) 14.1_(-1.0)^(+1.0) x 10^(14) M_â, demonstrating consistency between the complementary analysis methods
Coordinating vector field equations and diagrams with a serious game in introductory physics
Mathematical reasoning with algebraic and graphical representations is
essential for success in physics courses. Many problems require students to
fluently move between algebraic and graphical representations. We developed a
freely available serious game to challenge the representational fluency of
introductory students regarding vector fields. Within the game, interactive
puzzles are solved using different types of vector fields that must be
configured with the correct mathematical parameters. A reward system
implemented in the game prevents from using trial-and-error approaches and
instead encourages the player to establish a mental connection between the
graphical representation of the vector field and the (algebraic) equation
before taking any action. For correct solutions, the player receives points and
can unlock further levels. We report about the aim of the game from an
educational perspective, describe potential learning scenarios and reflect
about a first attempt to use the game in the classroom
CLASH: Joint Analysis of Strong-Lensing, Weak-Lensing Shear and Magnification Data for 20 Galaxy Clusters
We present a comprehensive analysis of strong-lensing, weak-lensing shear and magnification data for a sample of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19 ⟠z ⟠0.69 selected from Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis combines constraints from 16-band Hubble Space Telescope observations and wide-field multi-color imaging taken primarily with Suprime-Cam on the Subaru Telescope, spanning a wide range of cluster radii (10"â16'). We reconstruct surface mass density profiles of individual clusters from a joint analysis of the full lensing constraints, and determine masses and concentrations for all of the clusters. We find the internal consistency of the ensemble mass calibration to be â€5% ± 6% in the one-halo regime (200â2000 kpc hâ1) compared to the CLASH weak-lensing-only measurements of Umetsu et al. For the X-ray-selected subsample of 16 clusters, we examine the concentrationâmass (câM) relation and its intrinsic scatter using a Bayesian regression approach. Our model yields a mean concentration of c|_z=0.34 =3.95 ± 0.35 at M_(200c) â 14 Ă 10^(14) M_â and an intrinsic scatter of Ï(ln c_(200c) = 0.13 ± 0.06, which is in excellent agreement with Î cold dark matter predictions when the CLASH selection function based on X-ray morphological regularity and the projection effects are taken into account. We also derive an ensemble-averaged surface mass density profile for the X-ray-selected subsample by stacking their individual profiles. The stacked lensing signal is detected at 33Ï significance over the entire radial range â€4000 kpc h^(â1), accounting for the effects of intrinsic profile variations and uncorrelated large-scale structure along the line of sight. The stacked mass profile is well described by a family of density profiles predicted for cuspy dark-matter-dominated halos in gravitational equilibrium, namely, the NavarroâFrenkâWhite (NFW), Einasto, and DARKexp models, whereas the single power-law, cored isothermal and Burkert density profiles are disfavored by the data. We show that cuspy halo models that include the large-scale two-halo term provide improved agreement with the data. For the NFW halo model, we measure a mean concentration of c_(200c) = 3.79_(-0.28)^(+0.30) at M_(200c) 14.1_(-1.0)^(+1.0) x 10^(14) M_â, demonstrating consistency between the complementary analysis methods
CLASH: Weak-Lensing Shear-and-Magnification Analysis of 20 Galaxy Clusters
We present a joint shear-and-magnification weak-lensing analysis of a sample
of 16 X-ray-regular and 4 high-magnification galaxy clusters at 0.19<z<0.69
selected from the Cluster Lensing And Supernova survey with Hubble (CLASH). Our
analysis uses wide-field multi-color imaging, taken primarily with Suprime-Cam
on the Subaru Telescope. From a stacked shear-only analysis of the
X-ray-selected subsample, we detect the ensemble-averaged lensing signal with a
total signal-to-noise ratio of ~25 in the radial range of 200 to 3500kpc/h. The
stacked tangential-shear signal is well described by a family of standard
density profiles predicted for dark-matter-dominated halos in gravitational
equilibrium, namely the Navarro-Frenk-White (NFW), truncated variants of NFW,
and Einasto models. For the NFW model, we measure a mean concentration of
at . We show this is in excellent agreement with Lambda
cold-dark-matter (LCDM) predictions when the CLASH X-ray selection function and
projection effects are taken into account. The best-fit Einasto shape parameter
is , which is consistent with the
NFW-equivalent Einasto parameter of . We reconstruct projected mass
density profiles of all CLASH clusters from a joint likelihood analysis of
shear-and-magnification data, and measure cluster masses at several
characteristic radii. We also derive an ensemble-averaged total projected mass
profile of the X-ray-selected subsample by stacking their individual mass
profiles. The stacked total mass profile, constrained by the
shear+magnification data, is shown to be consistent with our shear-based
halo-model predictions including the effects of surrounding large-scale
structure as a two-halo term, establishing further consistency in the context
of the LCDM model.Comment: Accepted by ApJ on 11 August 2014. Textual changes to improve clarity
(e.g., Sec.3.2.2 "Number-count Depletion", Sec.4.3 "Shape Measurement",
Sec.4.4 "Background Galaxy Selection"). Results and conclusions remain
unchanged. For the public release of Subaru data, see
http://archive.stsci.edu/prepds/clash
The Detection and Statistics of Giant Arcs Behind CLASH Clusters
We developed an algorithm to find and characterize gravitationally lensed galaxies (arcs) to perform a comparison of the observed and simulated arc abundance. Observations are from the Cluster Lensing And Supernova survey with Hubble (CLASH). Simulated CLASH images are created using the MOKA package and also clusters selected from the high-resolution, hydrodynamical simulations, MUSIC, over the same mass and redshift range as the CLASH sample. The algorithm's arc elongation accuracy, completeness, and false positive rate are determined and used to compute an estimate of the true arc abundance. We derive a lensing efficiency of 4 ± 1 arcs (with length â„6'' and length-to-width ratio â„7) per cluster for the X-ray-selected CLASH sample, 4 ± 1 arcs per cluster for the MOKA-simulated sample, and 3 ± 1 arcs per cluster for the MUSIC-simulated sample. The observed and simulated arc statistics are in full agreement. We measure the photometric redshifts of all detected arcs and find a median redshift z_s = 1.9 with 33% of the detected arcs having z_s > 3. We find that the arc abundance does not depend strongly on the source redshift distribution but is sensitive to the mass distribution of the dark matter halos (e.g., the câM relation). Our results show that consistency between the observed and simulated distributions of lensed arc sizes and axial ratios can be achieved by using cluster-lensing simulations that are carefully matched to the selection criteria used in the observations
Hubble Space Telescope Combined Strong and Weak Lensing Analysis of the CLASH Sample: Mass and Magnification Models and Systematic Uncertainties
We present results from a comprehensive lensing analysis in HST data, of the
complete CLASH cluster sample. We identify new multiple-images previously
undiscovered allowing improved or first constraints on the cluster inner mass
distributions and profiles. We combine these strong-lensing constraints with
weak-lensing shape measurements within the HST FOV to jointly constrain the
mass distributions. The analysis is performed in two different common
parameterizations (one adopts light-traces-mass for both galaxies and dark
matter while the other adopts an analytical, elliptical NFW form for the dark
matter), to provide a better assessment of the underlying systematics - which
is most important for deep, cluster-lensing surveys, especially when studying
magnified high-redshift objects. We find that the typical (median), relative
systematic differences throughout the central FOV are in the
(dimensionless) mass density, , and in the magnification,
. We show maps of these differences for each cluster, as well as the mass
distributions, critical curves, and 2D integrated mass profiles. For the
Einstein radii () we find that all typically agree within
between the two models, and Einstein masses agree, typically, within
. At larger radii, the total projected, 2D integrated mass profiles
of the two models, within r\sim2\arcmin, differ by . Stacking the
surface-density profiles of the sample from the two methods together, we obtain
an average slope of , in the radial
range [5,350] kpc. Lastly, we also characterize the behavior of the average
magnification, surface density, and shear differences between the two models,
as a function of both the radius from the center, and the best-fit values of
these quantities.Comment: 35 pages (20 main text pages, plus 15 pages for additional figures
and tables); 2 Tables, 17 Figures. V3: accepted version; some minor
corrections and additions made. V4: corrected several entries in Table 2. All
mass models and magnification maps are made publicly available for the
communit
Bewertung der Vor- und Nachteile von Wasserstoffimporten im Vergleich zur heimischen Erzeugung - Update : Studie fĂŒr den Landesverband Erneuerbare Energien NRW e.V. (LEE-NRW)
Deutschlands Klimaschutzstrategie baut auf den Einsatz von grĂŒnem Wasserstoff aus erneuerbaren Energien. Doch wo soll der Wasserstoff herkommen, aus heimischer Produktion oder importiert aus dem Ausland? Eine Studie des Wuppertal Instituts und DIW Econ schafft einen Ăberblick ĂŒber die aktuelle Datenlage und ermittelt Wertschöpfungs- und BeschĂ€ftigungseffekte beider Strategien. Das ResĂŒmee: Es trifft nicht zu, dass importierter Wasserstoff allgemein gĂŒnstiger ist, entscheidend sind je nach Herkunftsland die tatsĂ€chlich realisierbaren Strom- und Transportkosten. Wird der grĂŒne Wasserstoff stattdessen im eigenen Land produziert, wird dies zudem eine positive BeschĂ€ftigungswirkung und Wertschöpfung entfalten. Mit der Erreichung der Klimaziele 2050 betrĂŒge die zusĂ€tzliche Wertschöpfung bei einer stark auf die heimische Erzeugung ausgerichtete Strategie bis zu 30 Milliarden Euro im Jahr 2050 und es könnten bis zu 800.000 ArbeitsplĂ€tze geschaffen werden
GC-MS-based urine metabolic profiling of autism spectrum disorders.: GC-MS-based Urine Metabolic Profiling in ASD
International audienceAutism spectrum disorders (ASD) are a group of neurodevelopmental disorders resulting from multiple factors. Diagnosis is based on behavioural and developmental signs detected before 3 years of age, and there is no reliable biological marker. The purpose of this study was to evaluate the value of gas chromatography combined with mass spectroscopy (GC-MS) associated with multivariate statistical modeling to capture the global biochemical signature of autistic individuals. GC-MS urinary metabolic profiles of 26 autistic and 24 healthy children were obtained by liq/liq extraction, and were or were not subjected to an oximation step, and then were subjected to a persilylation step. These metabolic profiles were then processed by multivariate analysis, in particular orthogonal partial least-squares discriminant analysis (OPLS-DA, R(2)Y(cum) = 0.97, Q(2)(cum) = 0.88). Discriminating metabolites were identified. The relative concentrations of the succinate and glycolate were higher for autistic than healthy children, whereas those of hippurate, 3-hydroxyphenylacetate, vanillylhydracrylate, 3-hydroxyhippurate, 4-hydroxyphenyl-2-hydroxyacetate, 1H-indole-3-acetate, phosphate, palmitate, stearate, and 3-methyladipate were lower. Eight other metabolites, which were not identified but characterized by a retention time plus a quantifier and its qualifier ion masses, were found to differ between the two groups. Comparison of statistical models leads to the conclusion that the combination of data obtained from both derivatization techniques leads to the model best discriminating between autistic and healthy groups of children
Retest variability and patient reliability indices of quantitative fundus autofluorescence in age-related macular degeneration: a MACUSTAR study report
This study aimed to determine the retest variability of quantitative fundus autofluorescence (QAF) in patients with and without age-related macular degeneration (AMD) and evaluate the predictive value of patient reliability indices on retest reliability. A total of 132 eyes from 68 patients were examined, including healthy individuals and those with various stages of AMD. Duplicate QAF imaging was conducted at baseline and 2 weeks later across six study sites. Intraclass correlation (ICC) analysis was used to evaluate the consistency of imaging, and mean opinion scores (MOS) of image quality were generated by two researchers. The contribution of MOS and other factors to retest variation was assessed using mixed-effect linear models. Additionally, a Random Forest Regressor was trained to evaluate the extent to which manual image grading of image quality could be replaced by automated assessment (inferred MOS). The results showed that ICC values were high for all QAF images, with slightly lower values in AMD-affected eyes. The average inter-day ICC was found to be 0.77 for QAF segments within the QAF8 ring and 0.74 for peripheral segments. Image quality was predicted with a mean absolute error of 0.27 on a 5-point scale, and of all evaluated reliability indices, MOS/inferred MOS proved most important. The findings suggest that QAF allows for reliable testing of autofluorescence levels at the posterior pole in patients with AMD in a multicenter, multioperator setting. Patient reliability indices could serve as eligibility criteria for clinical trials, helping identify patients with adequate retest reliability
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