Showing papers by "August E. Evrard published in 2019"

First cosmological results using Type Ia supernovae from the Dark Energy Survey: Measurement of the Hubble constant

Abstract: We present an improved measurement of the Hubble constant (H0) using the 'inverse distance ladder' method, which adds the information from 207 Type Ia supernovae (SNe Ia) from the Dark Energy Survey (DES) at redshift 0.018

Dark Energy Survey year 1 results: Constraints on extended cosmological models from galaxy clustering and weak lensing

Abstract: We present constraints on extensions of the minimal cosmological models dominated by dark matter and dark energy, ΛCDM and wCDM, by using a combined analysis of galaxy clustering and weak gravitational lensing from the first-year data of the Dark Energy Survey (DES Y1) in combination with external data. We consider four extensions of the minimal dark energy-dominated scenarios: (1) nonzero curvature ωk, (2) number of relativistic species Neff different from the standard value of 3.046, (3) time-varying equation-of-state of dark energy described by the parameters w0 and wa (alternatively quoted by the values at the pivot redshift, wp, and wa), and (4) modified gravity described by the parameters μ0 and ς0 that modify the metric potentials. We also consider external information from Planck cosmic microwave background measurements; baryon acoustic oscillation measurements from SDSS, 6dF, and BOSS; redshift-space distortion measurements from BOSS; and type Ia supernova information from the Pantheon compilation of datasets. Constraints on curvature and the number of relativistic species are dominated by the external data; when these are combined with DES Y1, we find ωk=0.0020-0.0032+0.0037 at the 68% confidence level, and the upper limit Neff 3.0. For the time-varying equation-of-state, we find the pivot value (wp,wa)=(-0.91-0.23+0.19,-0.57-1.11+0.93) at pivot redshift zp=0.27 from DES alone, and (wp,wa)=(-1.01-0.04+0.04,-0.28-0.48+0.37) at zp=0.20 from DES Y1 combined with external data; in either case we find no evidence for the temporal variation of the equation of state. For modified gravity, we find the present-day value of the relevant parameters to be ς0=0.43-0.29+0.28 from DES Y1 alone, and (ς0,μ0)=(0.06-0.07+0.08,-0.11-0.46+0.42) from DES Y1 combined with external data. These modified-gravity constraints are consistent with predictions from general relativity.

First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary-Black-hole Merger GW170814

Abstract: We present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in ${H}_{0}={75}_{-32}^{+40}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find ${H}_{0}={78}_{-24}^{+96}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0.

First measurement of the Hubble constant from a dark standard siren using the Dark Energy Survey galaxies and the LIGO/Virgo binary-black-hole merger GW170814

Abstract: We present a multi-messenger measurement of the Hubble constant H_0 using the binary-black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the LIGO/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black-hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black-hole merger. Our analysis results in $H_0 = 75.2^{+39.5}_{-32.4}~{\rm km~s^{-1}~Mpc^{-1}}$, which is consistent with both SN Ia and CMB measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20,140] ${\rm km~s^{-1}~Mpc^{-1}}$, and it depends on the assumed prior range. If we take a broader prior of [10,220] ${\rm km~s^{-1}~Mpc^{-1}}$, we find $H_0 = 78^{+ 96}_{-24}~{\rm km~s^{-1}~Mpc^{-1}}$ ($57\%$ of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on $H_0$.

Dark Energy Survey Year 1 Results: Measurement of the Baryon Acoustic Oscillation scale in the distribution of galaxies to redshift 1

Abstract: Ohio State University Center for Cosmology and AstroParticle Physics; Spanish Ramon y Cajal MICINN program; Spanish Ministerio de Economia y Competitividad [ESP2013-48274-C3-1-P]; Juan de la Cierva fellowship; Brazilian Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Sao Paulo Research Foundation (FAPESP); CNPq; Instituto Nacional de Ciencia e Tecnologia (INCT) e-Universe (CNPq) [465376/2014-2]; 'Plan Estatal de Investigacion Cientfica y Tecnica y de Innovacion' program of the Spanish government; U.S. Department of Energy; U.S. National Science Foundation; Ministry of Science and Education of Spain; Science and Technology Facilities Council of the United Kingdom; Higher Education Funding Council for England; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; Kavli Institute of Cosmological Physics at the University of Chicago; Center for Cosmology and Astro-Particle Physics at the Ohio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e Projetos; Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico; Ministerio da Ciencia, Tecnologia e Inovacao; Deutsche Forschungsgemeinschaft; Argonne National Laboratory; University of California at Santa Cruz; University of Cambridge; Centro de Investigaciones Energeticas; Medioambientales y Tecnologicas-Madrid; University of Chicago; University College London; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) Zurich; Fermi National Accelerator Laboratory; University of Illinois at Urbana-Champaign; Institut de Ciencies de l'Espai (IEEC/CSIC); Institut de Fisica d'Altes Energies; Lawrence Berkeley National Laboratory; Ludwig-Maximilians Universitat Munchen; associated Excellence Cluster Universe; University of Michigan; National Optical Astronomy Observatory; University of Nottingham; Ohio State University; University of Pennsylvania; University of Portsmouth; SLAC National Accelerator Laboratory; Stanford University; University of Sussex; Texas AM University; OzDES Membership Consortium; National Science Foundation [AST-1138766, AST-1536171]; MINECO [AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-2016-0597, MDM-2015-0509]; ERDF funds from the European Union; CERCA program of the Generalitat de Catalunya; European Research Council under the European Union; ERC [240672, 291329, 306478]; Australian Research Council Centre of Excellence [CE110001020]; U.S. Department of Energy, Office of Science, Office of High Energy Physics [DE-AC02-07CH11359]

Dark Energy Survey Year 1 results: weak lensing mass calibration of redMaPPer galaxy clusters

Abstract: We constrain the mass--richness scaling relation of redMaPPer galaxy clusters identified in the Dark Energy Survey Year 1 data using weak gravitational lensing. We split clusters into 4×3 bins of richness λ and redshift z for λ≥20 and 0.2≤z≤0.65 and measure the mean masses of these bins using their stacked weak lensing signal. By modeling the scaling relation as ⟨M 200m |λ,z⟩=M 0 (λ/40) F ((1+z)/1.35) G , we constrain the normalization of the scaling relation at the 5.0 per cent level as M 0 =[3.081±0.075(stat)±0.133(sys)]⋅10 14 M ⊙ at λ=40 and z=0.35 . The richness scaling index is constrained to be F=1.356±0.051 (stat)±0.008 (sys) and the redshift scaling index G=−0.30±0.30 (stat)±0.06 (sys) . These are the tightest measurements of the normalization and richness scaling index made to date. We use a semi-analytic covariance matrix to characterize the statistical errors in the recovered weak lensing profiles. Our analysis accounts for the following sources of systematic error: shear and photometric redshift errors, cluster miscentering, cluster member dilution of the source sample, systematic uncertainties in the modeling of the halo--mass correlation function, halo triaxiality, and projection effects. We discuss prospects for reducing this systematic error budget, which dominates the uncertainty on M 0. Our result is in excellent agreement with, but has significantly smaller uncertainties than, previous measurements in the literature, and augurs well for the power of the DES cluster survey as a tool for precision cosmology and upcoming galaxy surveys such as LSST, Euclid and WFIRST.

Cosmological constraints from multiple probes in the Dark Energy Survey

Abstract: The combination of multiple observational probes has long been advocated as a powerful technique to constrain cosmological parameters, in particular dark energy. The Dark Energy Survey has measured 207 spectroscopically confirmed type Ia supernova light curves, the baryon acoustic oscillation feature, weak gravitational lensing, and galaxy clustering. Here we present combined results from these probes, deriving constraints on the equation of state, w, of dark energy and its energy density in the Universe. Independently of other experiments, such as those that measure the cosmic microwave background, the probes from this single photometric survey rule out a Universe with no dark energy, finding w=-0.80_{-0.11}^{+0.09}. The geometry is shown to be consistent with a spatially flat Universe, and we obtain a constraint on the baryon density of Ω_{b}=0.069_{-0.012}^{+0.009} that is independent of early Universe measurements. These results demonstrate the potential power of large multiprobe photometric surveys and pave the way for order of magnitude advances in our constraints on properties of dark energy and cosmology over the next decade.

Transfer learning for galaxy morphology from one survey to another

Abstract: © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.

Three new VHS-DES quasars at 6.7 6.5

Abstract: We report the results from a search for z > 6.5 quasars using the Dark Energy Survey (DES) Year 3 dataset combined with the VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey. Our photometric selection method is shown to be highly efficient in identifying clean samples of high-redshift quasars leading to spectroscopic confirmation of three new quasars - VDESJ 0244-5008 (z=6.724), VDESJ 0020-3653 (z=6.834) and VDESJ 0246-5219 (z=6.90) - which were selected as the highest priority candidates in the survey data without any need for additional follow-up observations. The new quasars span the full range in luminosity covered by other z>6.5 quasar samples (J AB = 20.2 to 21.3; M1450 = -25.6 to -26.6). We have obtained spectroscopic observations in the near infrared for VDESJ 0244-5008 and VDESJ 0020-3653 as well as our previously identified quasar, VDESJ 0224-4711 at z=6.50 from Reed et al. (2017). We use the near infrared spectra to derive virial black-hole masses from the full-width-half-maximum of the MgII line. These black-hole masses are ~ 1 - 2 x 10$^9$M$_\odot$. Combining with the bolometric luminosities of these quasars of L$_{\rm{bol}}\simeq$ 1 - 3 x 10$^{47}$implies that the Eddington ratios are high - $\simeq$0.6-1.1. We consider the C\textrm{\textsc{IV}} emission line properties of the sample and demonstrate that our high-redshift quasars do not have unusual C\textrm{\textsc{IV}} line properties when compared to carefully matched low-redshift samples. Our new DES+VHS $z>6.5$ quasars now add to the growing census of luminous, rapidly accreting supermassive black-holes seen well into the epoch of reionisation.

Dark Energy Survey Year 1 Results: Detection of Intracluster Light at Redshift ∼ 0.25

Abstract: Using data collected by the Dark Energy Survey (DES), we report the detection of intracluster light (ICL) with ~300 galaxy clusters in the redshift range of 0.2–0.3. We design methods to mask detected galaxies and stars in the images and stack the cluster light profiles, while accounting for several systematic effects (sky subtraction, instrumental point-spread function, cluster selection effects, and residual light in the ICL raw detection from background and cluster galaxies). The methods allow us to acquire high signal-to-noise measurements of the ICL and central galaxies (CGs), which we separate with radial cuts. The ICL appears as faint and diffuse light extending to at least 1 Mpc from the cluster center, reaching a surface brightness level of 30 mag arcsec−2. The ICL and the cluster CG contribute 44% ± 17% of the total cluster stellar luminosity within 1 Mpc. The ICL color is overall consistent with that of the cluster red sequence galaxies, but displays the trend of becoming bluer with increasing radius. The ICL demonstrates an interesting self-similarity feature—for clusters in different richness ranges, their ICL radial profiles are similar after scaling with cluster R 200m , and the ICL brightness appears to be a good tracer of the cluster radial mass distribution. These analyses are based on the DES redMaPPer cluster sample identified in the first year of observations.

Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing

Abstract: Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on coarse measurements of spectral energy distributions in a few filters to estimate the redshift distribution of source galaxies. In this regime, sample variance, shot noise, and selection effects limit the attainable accuracy of redshift calibration and thus of cosmological constraints. We present a new method to combine wide-field, few-filter measurements with catalogues from deep fields with additional filters and sufficiently low photometric noise to break degeneracies in photometric redshifts. The multiband deep field is used as an intermediary between wide-field observations and accurate redshifts, greatly reducing sample variance, shot noise, and selection effects. Our implementation of the method uses self-organizing maps to group galaxies into phenotypes based on their observed fluxes, and is tested using a mock DES catalogue created from N-body simulations. It yields a typical uncertainty on the mean redshift in each of five tomographic bins for an idealized simulation of the DES Year 3 weak-lensing tomographic analysis of σ_(Δz) = 0.007, which is a 60 per cent improvement compared to the Year 1 analysis. Although the implementation of the method is tailored to DES, its formalism can be applied to other large photometric surveys with a similar observing strategy.

Dark Energy Survey Year 1 Results: Detection of Intracluster Light at Redshift similar to 0.25

Abstract: Using data collected by the Dark Energy Survey (DES), we report the detection of intracluster light (ICL) with ~300 galaxy clusters in the redshift range of 0.2–0.3. We design methods to mask detected galaxies and stars in the images and stack the cluster light profiles, while accounting for several systematic effects (sky subtraction, instrumental point-spread function, cluster selection effects, and residual light in the ICL raw detection from background and cluster galaxies). The methods allow us to acquire high signal-to-noise measurements of the ICL and central galaxies (CGs), which we separate with radial cuts. The ICL appears as faint and diffuse light extending to at least 1 Mpc from the cluster center, reaching a surface brightness level of 30 mag arcsec−2. The ICL and the cluster CG contribute 44% ± 17% of the total cluster stellar luminosity within 1 Mpc. The ICL color is overall consistent with that of the cluster red sequence galaxies, but displays the trend of becoming bluer with increasing radius. The ICL demonstrates an interesting self-similarity feature—for clusters in different richness ranges, their ICL radial profiles are similar after scaling with cluster R 200m , and the ICL brightness appears to be a good tracer of the cluster radial mass distribution. These analyses are based on the DES redMaPPer cluster sample identified in the first year of observations.

Dark Energy Survey Year 1 results: Methodology and projections for joint analysis of galaxy clustering, galaxy lensing, and CMB lensing two-point functions

Abstract: Optical imaging surveys measure both the galaxy density and the gravitational lensing-induced shear fields across the sky Recently, the Dark Energy Survey (DES) Collaboration used a joint fit to two-point correlations between these observables to place tight constraints on cosmology (T M C Abbott (Dark Energy Survey Collaboration), Phys Rev D 98, 043526 (2018)PRVDAQ2470-0010101103/PhysRevD98043526) In this work, we develop the methodology to extend the DES Year 1 joint probes analysis to include cross-correlations of the optical survey observables with gravitational lensing of the cosmic microwave background as measured by the South Pole Telescope (SPT) and Planck Using simulated analyses, we show how the resulting set of five two-point functions increases the robustness of the cosmological constraints to systematic errors in galaxy lensing shear calibration Additionally, we show that contamination of the SPT+Planck cosmic microwave background lensing map by the thermal Sunyaev-Zel'dovich effect is a potentially large source of systematic error for two-point function analyses but show that it can be reduced to acceptable levels in our analysis by masking clusters of galaxies and imposing angular scale cuts on the two-point functions The methodology developed here will be applied to the analysis of data from the DES, the SPT, and Planck in a companion work

On the relative bias of void tracers in the Dark Energy Survey

Abstract: Luminous tracers of large-scale structure are not entirely representative of the distribution of mass in our Universe. As they arise from the highest peaks in the matter density field, the spatial distribution of luminous objects is biased towards those peaks. On large scales, where density fluctuations are mild, this bias simply amounts to a constant offset in the clustering amplitude of the tracer, known as linear bias. In this work we focus on the relative bias between galaxies and galaxy clusters that are located inside and in the vicinity of cosmic voids, extended regions of relatively low density in the large-scale structure of the Universe. With the help of mock data we verify that the relation between galaxy and cluster overdensity around voids remains linear. Hence, the void-centric density profiles of different tracers can be linked by a single multiplicative constant. This amounts to the same value as the relative linear bias between tracers for the largest voids in the sample. For voids of small sizes, which typically arise in higher density regions, this constant has a higher value, possibly showing an environmental dependence similar to that observed for the linear bias itself. We confirm our findings by analysing data obtained during the first year of observations by the Dark Energy Survey. As a side product, we present the first catalogue of three-dimensional voids extracted from a photometric survey with a controlled photo-z uncertainty. Our results will be relevant in forthcoming analyses that attempt to use voids as cosmological probes.

Milky Way Satellite Census. II. Galaxy--Halo Connection Constraints Including the Impact of the Large Magellanic Cloud

Abstract: The population of Milky Way (MW) satellites contains the faintest known galaxies and thus provides essential insight into galaxy formation and dark matter microphysics. Here we combine a model of the galaxy--halo connection with newly derived observational selection functions based on searches for satellites in photometric surveys over nearly the entire high Galactic latitude sky. In particular, we use cosmological zoom-in simulations of MW-like halos that include realistic Large Magellanic Cloud (LMC) analogs to fit the position-dependent MW satellite luminosity function. We report decisive evidence for the statistical impact of the LMC on the MW satellite population due to an estimated $6\pm 2$ observed LMC-associated satellites, consistent with the number of LMC satellites inferred from Gaia proper-motion measurements, confirming the predictions of cold dark matter models for the existence of satellites within satellite halos. Moreover, we infer that the LMC fell into the MW within the last $2\ \rm{Gyr}$ at high confidence. Based on our detailed full-sky modeling, we find that the faintest observed satellites inhabit halos with peak virial masses below $3.2\times 10^{8}\ M_{\rm{\odot}}$ at $95\%$ confidence, and we place the first robust constraints on the fraction of halos that host galaxies in this regime. We predict that the faintest detectable satellites occupy halos with peak virial masses above $10^{6}\ M_{\rm{\odot}}$, highlighting the potential for powerful galaxy formation and dark matter constraints from future dwarf galaxy searches.

The Buzzard Flock: Dark Energy Survey Synthetic Sky Catalogs

Abstract: We present a suite of 18 synthetic sky catalogs designed to support science analysis of galaxies in the Dark Energy Survey Year 1 (DES Y1) data. For each catalog, we use a computationally efficient empirical approach, ADDGALS, to embed galaxies within light-cone outputs of three dark matter simulations that resolve halos with masses above ~5x10^12 h^-1 m_sun at z <= 0.32 and 10^13 h^-1 m_sun at z~2. The embedding method is tuned to match the observed evolution of galaxy counts at different luminosities as well as the spatial clustering of the galaxy population. Galaxies are lensed by matter along the line of sight --- including magnification, shear, and multiple images --- using CALCLENS, an algorithm that calculates shear with 0.42 arcmin resolution at galaxy positions in the full catalog. The catalogs presented here, each with the same LCDM cosmology (denoted Buzzard), contain on average 820 million galaxies over an area of 1120 square degrees with positions, magnitudes, shapes, photometric errors, and photometric redshift estimates. We show that the weak-lensing shear catalog, redMaGiC galaxy catalogs and redMaPPer cluster catalogs provide plausible realizations of the same catalogs in the DES Y1 data by comparing their magnitude, color and redshift distributions, angular clustering, and mass-observable relations, making them useful for testing analyses that use these samples. We make public the galaxy samples appropriate for the DES Y1 data, as well as the data vectors used for cosmology analyses on these simulations.

LoCuSS: scaling relations between galaxy cluster mass, gas, and stellar content

Abstract: STFC; NASA [G06-17116B]; McWilliams Postdoctoral Fellowship; Royal Society; NSF [AST-1140019]; PRIN INAF

Constraints on the redshift evolution of astrophysical feedback with Sunyaev-Zel'dovich effect cross-correlations

Abstract: U.S. National Science FoundationNational Science Foundation (NSF) [AST-1440226]; U.S. Department of EnergyUnited States Department of Energy (DOE) [DE-SC0007901]; Ministry of Science and Education of SpainMinistry of Education and Science, Spain; Science and Technology Facilities Council of the United KingdomScience & Technology Facilities Council (STFC); Higher Education Funding Council for EnglandHigher Education Funding Council for England; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; Center for Cosmology and Astro-Particle Physics at the Ohio State UniversityOhio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e ProjetosCiencia Tecnologia e Inovacao (FINEP); Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroCarlos Chagas Filho Foundation for Research Support of the State of Rio de Janeiro (FAPERJ); Conselho Nacional de Desenvolvimento Cientifico e TecnologicoNational Council for Scientific and Technological Development (CNPq); Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG); Collaborating Institutions in the Dark Energy Survey; University of California at Santa Cruz; University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) ZurichETH Zurich; Ludwig-Maximilians Universitat Munchen; University of Portsmouth; OzDES Membership Consortium; Association of Universities for Research in Astronomy (AURA); National Science FoundationNational Science Foundation (NSF) [AST-1138766, AST-1536171]; MINECOSpanish Ministry of Economy & Competitiveness [AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-2016-0597, MDM-2015-0509]; ERDFEuropean Union (EU); European Union - CERCA program of the Generalitat de Catalunya; European Research Council under the European UnionEuropean Research Council (ERC) [240672, 291329, 306478]; Brazilian Instituto Nacional de Ciencia e Tecnologia (INCT) e-Universe (CNPq)National Council for Scientific and Technological Development (CNPq) [465376/2014-2, DE-AC0207CH11359]; U.S. Department of Energy, Office of Science, Office of High Energy PhysicsUnited States Department of Energy (DOE); U.S. Department of EnergyUnited States Department of Energy (DOE); U.S. National Science FoundationNational Science Foundation (NSF); Kavli Institute of Cosmological Physics at the University of Chicago

Weak Lensing Analysis of SPT selected Galaxy Clusters using Dark Energy Survey Science Verification Data

Abstract: We present weak-lensing (WL) mass constraints for a sample of massive galaxy clusters detected by the South Pole Telescope (SPT) via the Sunyaev–Zel’dovich effect (SZE). We use griz imaging data obtained from the Science Verification (SV) phase of the Dark Energy Survey (DES) to fit the WL shear signal of 33 clusters in the redshift range 0.25 ≤ |$z$| ≤ 0.8 with NFW profiles and to constrain a four-parameter SPT mass–observable relation. To account for biases in WL masses, we introduce a WL mass to true mass scaling relation described by a mean bias and an intrinsic, lognormal scatter. We allow for correlated scatter within the WL and SZE mass–observable relations and use simulations to constrain priors on nuisance parameters related to bias and scatter from WL. We constrain the normalization of the ζ−M_500 relation, |$A_\mathrm{SZ}=12.0_{-6.7}^{+2.6}$| when using a prior on the mass slope B_SZ from the latest SPT cluster cosmology analysis. Without this prior, we recover |$A_\mathrm{SZ}=10.8_{-5.2}^{+2.3}$| and |$B_\mathrm{SZ}=1.30_{-0.44}^{+0.22}$|⁠. Results in both cases imply lower cluster masses than measured in previous work with and without WL, although the uncertainties are large. The WL derived value of B_SZ is |${\approx } 20{{\ \rm per\ cent}}$| lower than the value preferred by the most recent SPT cluster cosmology analysis. The method demonstrated in this work is designed to constrain cluster masses and cosmological parameters simultaneously and will form the basis for subsequent studies that employ the full SPT cluster sample together with the DES data.

Dark Energy Survey Year 1 results: The relationship between mass and light around cosmic voids

Abstract: What are the mass and galaxy profiles of cosmic voids? In this paper, we use two methods to extract voids in the Dark Energy Survey (DES) Year 1 redMaGiC galaxy sample to address this question. We use either 2D slices in projection, or the 3D distribution of galaxies based on photometric redshifts to identify voids. For the mass profile, we measure the tangential shear profiles of background galaxies to infer the excess surface mass density. The signal-to-noise ratio for our lensing measurement ranges between 10.7 and 14.0 for the two void samples. We infer their 3D density profiles by fitting models based on N-body simulations and find good agreement for void radii in the range 15–85 Mpc. Comparison with their galaxy profiles then allows us to test the relation between mass and light at the 10 per cent level, the most stringent test to date. We find very similar shapes for the two profiles, consistent with a linear relationship between mass and light both within and outside the void radius. We validate our analysis with the help of simulated mock catalogues and estimate the impact of photometric redshift uncertainties on the measurement. Our methodology can be used for cosmological applications, including tests of gravity with voids. This is especially promising when the lensing profiles are combined with spectroscopic measurements of void dynamics via redshift-space distortions.

H0LiCOW – X. Spectroscopic/imaging survey and galaxy-group identification around the strong gravitational lens system WFI 2033−4723

Abstract: Swiss National Science FoundationSwiss National Science Foundation (SNSF); European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programmeEuropean Research Council (ERC) [787886]; World Premier International Research Center Initiative (WPI Initiative), MEXT, JapanMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT); Packard FoundationThe David & Lucile Packard Foundation; NSFNational Science Foundation (NSF) [AST-1450141, AST-1312329]; Max Planck Society through the Max Planck Research Group; EACOA Fellowship - East Asia Core Observatories Association, Academia Sinica Institute of Astronomy and Astrophysics; National Astronomical Observatory of JapanNational Institutes of Natural Sciences (NINS) - Japan; National Astronomical Observatories of the Chinese Academy of Sciences; Korea Astronomy and Space Science Institute; DFG cluster of excellence 'Origin and Structure of the Universe'German Research Foundation (DFG); NASA through STSCI grant [HSTGO-15320]; U.S. Department of EnergyUnited States Department of Energy (DOE) [DE-AC02-76SF00515]; NWO-VICI career grant [639.043.308]; European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme(s) [091.A-0642(A), 074.A-0302(A), 60.A-9306(A), 097.A-0454(A), 090.A-0531(A)]; U.S. Department of EnergyUnited States Department of Energy (DOE); U.S. National Science FoundationNational Science Foundation (NSF); Ministry of Science and Education of SpainMinistry of Education and Science, Spain; Science and Technology Facilities Council of the United KingdomScience & Technology Facilities Council (STFC); Higher Education Funding Council for EnglandHigher Education Funding Council for England; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; Kavli Institute of Cosmological Physics at the University of Chicago; Center for Cosmology and Astro-Particle Physics at the Ohio State UniversityOhio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e ProjetosCiencia Tecnologia e Inovacao (FINEP); Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Cientifico e TecnologicoNational Council for Scientific and Technological Development (CNPq); Ministerio da Ciencia, Tecnologia e Inovacao; Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG); Argonne National LaboratoryUnited States Department of Energy (DOE)University of Chicago; University of California at Santa Cruz; University of CambridgeUniversity of Cambridge; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid; University of ChicagoUniversity of Chicago; University College London; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) ZurichETH Zurich; Fermi National Accelerator LaboratoryUnited States Department of Energy (DOE)University of Chicago; University of Illinois at Urbana-Champaign; Institut de Ciencies de l'Espai (IEEC/CSIC); Institut de Fisica d'Altes Energies; Lawrence Berkeley National LaboratoryUnited States Department of Energy (DOE); Ludwig-Maximilians Universitat Munchen; associated Excellence Cluster Universe; University of MichiganUniversity of Michigan System; National Optical Astronomy ObservatoryNational Science Foundation (NSF)NSF - Directorate for Mathematical & Physical Sciences (MPS); University of Nottingham; Ohio State UniversityOhio State University; University of Pennsylvania; University of Portsmouth; SLAC National Accelerator Laboratory; Stanford UniversityStanford University; University of Sussex; Texas AM University; OzDES Membership Consortium; National Science FoundationNational Science Foundation (NSF) [AST-1138766, AST-1536171]; MINECO [AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV-20160597, MDM-2015-0509]; ERDF funds from the European Union; CERCA program of the Generalitat de Catalunya; European Research Council under the European Union's Seventh Framework Program (FP7/2007-2013); ERCEuropean Research Council (ERC) [240672, 291329, 306478]; Brazilian Instituto Nacional de Ciencia e Tecnologia (INCT) e-Universe (CNPq)National Council for Scientific and Technological Development (CNPq) [465376/2014-2]; U.S. Department of Energy, Office of Science, Office of High Energy PhysicsUnited States Department of Energy (DOE) [DE-AC02-07CH11359]; NASANational Aeronautics & Space Administration (NASA) [NAS 5-26555]; NASA through Space Telescope Science InstituteSpace Telescope Science Institute [12889]; National Aeronautics and Space AdministrationNational Aeronautics & Space Administration (NASA); National Science FoundationNational Science Foundation (NSF)

Dark Energy Survey Year 1 results: measurement of the galaxy angular power spectrum

Abstract: We use data from the first-year observations of the DES collaboration to measure the galaxy angular power spectrum (APS), and search for its BAO feature. We test our methodology in a sample of 1800 DES Y1-like mock catalogues. We use the pseudo-C_l method to estimate the APS and the mock catalogues to estimate its covariance matrix. We use templates to model the measured spectra and estimate template parameters firstly from the C_l’s of the mocks using two different methods, a maximum likelihood estimator and a Markov Chain Monte Carlo, finding consistent results with a good reduced χ^2. Robustness tests are performed to estimate the impact of different choices of settings used in our analysis. Finally, we apply our method to a galaxy sample constructed from DES Y1 data specifically for LSS studies. This catalogue comprises galaxies within an effective area of 1318 deg^2 and 0.6 < z < 1.0. We find that the DES Y1 data favour a model with BAO at the |$2.6 \sigma$| C.L. However, the goodness of fit is somewhat poor, with χ^2/(d.o.f.) = 1.49. We identify a possible cause showing that using a theoretical covariance matrix obtained from C_l’s that are better adjusted to data results in an improved value of χ^2/(dof) = 1.36 which is similar to the value obtained with the real-space analysis. Our results correspond to a distance measurement of (z_eff = 0.81)/r_d = 10.65 ± 0.49, consistent with the main DES BAO findings. This is a companion paper to the main DES BAO article showing the details of the harmonic space analysis.

Dark Energy Survey Year 1 results: validation of weak lensing cluster member contamination estimates from P(z) decomposition

Abstract: Deutsche Forschungsgemeinschaft (DFG)German Research Foundation (DFG) [SFB-Transregio 33]; DFG cluster of excellence 'Origin and Structure of the Universe'German Research Foundation (DFG); U.S. Department of EnergyUnited States Department of Energy (DOE); DOEUnited States Department of Energy (DOE); Sloan FoundationAlfred P. Sloan Foundation [DE-SC0015975]; Cottrell Scholar program of the Research Corporation for Science Advancement [FG-2016-6443]; National Aeronautics and Space AdministrationNational Aeronautics & Space Administration (NASA); Stanford UniversityStanford University; Office of Science of the U.S. Department of EnergyUnited States Department of Energy (DOE) [DE-AC02-05CH11231]; U.S. National Science FoundationNational Science Foundation (NSF); Ministry of Science and Education of SpainMinistry of Education and Science, Spain; Science and Technology Facilities Council of the United KingdomScience & Technology Facilities Council (STFC); Higher Education Funding Council for EnglandHigher Education Funding Council for England; Center for Cosmology and Astro-Particle Physics at the Ohio State UniversityOhio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e ProjetosCiencia Tecnologia e Inovacao (FINEP); Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Cientifico e TecnologicoNational Council for Scientific and Technological Development (CNPq); Deutsche ForschungsgemeinschaftGerman Research Foundation (DFG); University of California at Santa Cruz; University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) ZurichETH Zurich; Ludwig-Maximilians Universitat Munchen; University of Portsmouth; OzDES Membership Consortium; National Science FoundationNational Science Foundation (NSF) [AST-1138766, AST-1536171]; MINECO; ERDFEuropean Union (EU) [AYA201571825, ESP2015-66861, FPA2015-68048, SEV-2016-0588, SEV2016-0597, MDM-2015-0509]; European Union - CERCA program of the Generalitat de Catalunya; European Research Council under the European UnionEuropean Research Council (ERC) [240672, 291329, 306478]; Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO)Australian Research Council; Brazilian Instituto Nacional de Ciencia e Tecnologia (INCT) e-Universe (CNPq)National Council for Scientific and Technological Development (CNPq) [CE110001020]; U.S. Department of Energy, Office of Science, Office of High Energy PhysicsUnited States Department of Energy (DOE) [465376/2014-2, DE-AC02-07CH11359]

Cosmological lensing ratios with DES Y1, SPT, and Planck

Abstract: Correlations between tracers of the matter density field and gravitational lensing are sensitive to the evolution of the matter power spectrum and the expansion rate across cosmic time. Appropriately defined ratios of such correlation functions, on the other hand, depend only on the angular diameter distances to the tracer objects and to the gravitational lensing source planes. Because of their simple cosmological dependence, such ratios can exploit available signal-to-noise ratio down to small angular scales, even where directly modelling the correlation functions is difficult. We present a measurement of lensing ratios using galaxy position and lensing data from the Dark Energy Survey, and CMB lensing data from the South Pole Telescope and Planck, obtaining the highest precision lensing ratio measurements to date. Relative to the concordance ΛCDM model, we find a best-fitting lensing ratio amplitude of A = 1.1 ± 0.1. We use the ratio measurements to generate cosmological constraints, focusing on the curvature parameter. We demonstrate that photometrically selected galaxies can be used to measure lensing ratios, and argue that future lensing ratio measurements with data from a combination of LSST and Stage-4 CMB experiments can be used to place interesting cosmological constraints, even after considering the systematic uncertainties associated with photometric redshift and galaxy shear estimation.

Detection of CMB-Cluster Lensing using Polarization Data from SPTpol.

Abstract: We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500 deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{⊙} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.

The Future Landscape of High-Redshift Galaxy Cluster Science.

Abstract: Modern galaxy cluster science is a multi-wavelength endeavor with cornerstones provided by X-ray, optical/IR, mm, and radio measurements. In combination, these observations enable the construction of large, clean, complete cluster catalogs, and provide precise redshifts and robust mass calibration. The complementary nature of these multi-wavelength data dramatically reduces the impact of systematic effects that limit the utility of measurements made in any single waveband. The future of multi-wavelength cluster science is compelling, with cluster catalogs set to expand by orders of magnitude in size, and extend, for the first time, into the high-redshift regime where massive, virialized structures first formed. Unlocking astrophysical and cosmological insight from the coming catalogs will require new observing facilities that combine high spatial and spectral resolution with large collecting areas, as well as concurrent advances in simulation modeling campaigns. Together, future multi-wavelength observations will resolve the thermodynamic structure in and around the first groups and clusters, distinguishing the signals from active and star-forming galaxies, and unveiling the interrelated stories of galaxy evolution and structure formation during the epoch of peak cosmic activity.

The Future Landscape of High-Redshift Galaxy Cluster Science

Abstract: We describe the opportunities for galaxy cluster science in the high- redshift regime where massive, virialized halos first formed and where star formation and AGN activity peaked. New observing facilities from radio to X-ray wavelengths, combining high spatial/spectral resolution with large collecting areas, are poised to uncover this population.

Withdrawn as Duplicate: Survey geometry and the internal consistency of recent cosmic shear measurements

Abstract: M. A. Troxel, E. Krause, C. Chang, T. F. Eifler, O. Friedrich, D. Gruen, N. MacCrann, A. Chen, C. Davis, J. DeRose, S. Dodelson, M. Gatti, B. Hoyle, D. Huterer, M. Jarvis, F. Lacasa, P. Lemos, H. V. Peiris, J. Prat, S. Samuroff, C. Sánchez, E. Sheldon, P. Vielzeuf, M. Wang, J. Zuntz, O. Lahav, F. B. Abdalla, S. Allam, J. Annis, S. Avila, E. Bertin, D. Brooks, D. L. Burke, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, M. Crocce, C. E. Cunha, C. B. D’Andrea, L. N. da Costa, J. De Vicente, H. T. Diehl, P. Doel, A. E. Evrard, B. Flaugher, P. Fosalba, J. Frieman, J. Garcı́a-Bellido, E. Gaztanaga, D. W. Gerdes, R. A. Gruendl, J. Gschwend, G. Gutierrez, W. G. Hartley, D. L. Hollowood, K. Honscheid, D. J. James, D. Kirk, K. Kuehn, N. Kuropatkin, T. S. Li, M. Lima, M. March, F. Menanteau, R. Miquel, J. J. Mohr, R. L. C. Ogando, A. A. Plazas, A. Roodman, E. Sanchez, V. Scarpine, R. Schindler, I. Sevilla-Noarbe, M. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E. C. Swanson, D. Thomas, A. R. Walker and R. H. Wechsler