Showing papers by "Risa H. Wechsler published in 2019"
TL;DR: Giacconi Fellowship from the Space Telescope Science Institute; NASA through a Hubble Fellowship grant from NASA's HST-HF2-51353.001-A; NASANational Aeronautics & Space Administration (NAS5-26555); NSFNational Science Foundation (NSF) [1066293]; National Science Foundation(NSF)'s National Research Foundation (NRF) [PHY11-25915]; Munich Institute for Astro-and Particle Physics (MIAPP) of the DFG cluster of excellence 'Origin and Structure of the Universe'
Abstract: Giacconi Fellowship from the Space Telescope Science Institute; NASA through a Hubble Fellowship grant from the Space Telescope Science Institute [HST-HF2-51353.001-A]; NASANational Aeronautics & Space Administration (NASA) [NAS5-26555]; NSFNational Science Foundation (NSF) [1066293]; National Science Foundation (NSF)National Science Foundation (NSF) [PHY11-25915]; Munich Institute for Astro-and Particle Physics (MIAPP) of the DFG cluster of excellence 'Origin and Structure of the Universe; Office of Science of the U.S. Department of EnergyUnited States Department of Energy (DOE) [DE-AC02-05CH11231]; DOEUnited States Department of Energy (DOE) [DE-AC02-76SF00515]; NASA High-EndComputing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center; PRACE [012060963]; Alfred P. Sloan FoundationAlfred P. Sloan Foundation; U.S. Department of Energy Office of ScienceUnited States Department of Energy (DOE); University of Arizona; Brazilian Participation Group; Brookhaven National LaboratoryUnited States Department of Energy (DOE); Carnegie Mellon University; French Participation Group; German Participation Group; Harvard University; Instituto de Astrofisica de Canarias; Michigan State/Notre Dame/JINA Participation Group; Johns Hopkins UniversityJohns Hopkins University; Lawrence Berkeley National LaboratoryUnited States Department of Energy (DOE); Max Planck Institute for Astrophysics; Max Planck Institute for Extraterrestrial Physics; Pennsylvania State University; Princeton UniversityPrinceton University; Spanish Participation Group; Yale University; University of FloridaUniversity of Florida; NewMexico State University; New York University; Ohio State UniversityOhio State University; University of Portsmouth; University of Tokyo; University of Utah; Vanderbilt University; University of Virginia; University of WashingtonUniversity of Washington
612 citations
TL;DR: The DESI Legacy Imaging Surveys (http://legacysurvey.org/) as mentioned in this paper is a combination of three public projects (the Dark Energy Camera Legacy Survey, the Beijing-Arizona Sky Survey, and the Mayall z-band Legacy Survey) that will jointly image ≈14,000 deg2 of the extragalactic sky visible from the northern hemisphere in three optical bands (g, r, and z) using telescopes at the Kitt Peak National Observatory and the Cerro Tololo Inter-American Observatory.
Abstract: The DESI Legacy Imaging Surveys (http://legacysurvey.org/) are a combination of three public projects (the Dark Energy Camera Legacy Survey, the Beijing–Arizona Sky Survey, and the Mayall z-band Legacy Survey) that will jointly image ≈14,000 deg2 of the extragalactic sky visible from the northern hemisphere in three optical bands (g, r, and z) using telescopes at the Kitt Peak National Observatory and the Cerro Tololo Inter-American Observatory. The combined survey footprint is split into two contiguous areas by the Galactic plane. The optical imaging is conducted using a unique strategy of dynamically adjusting the exposure times and pointing selection during observing that results in a survey of nearly uniform depth. In addition to calibrated images, the project is delivering a catalog, constructed by using a probabilistic inference-based approach to estimate source shapes and brightnesses. The catalog includes photometry from the grz optical bands and from four mid-infrared bands (at 3.4, 4.6, 12, and 22 μm) observed by the Wide-field Infrared Survey Explorer satellite during its full operational lifetime. The project plans two public data releases each year. All the software used to generate the catalogs is also released with the data. This paper provides an overview of the Legacy Surveys project.
517 citations
TL;DR: In this paper, the authors 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.
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.
161 citations
Marcelle Soares-Santos1, Antonella Palmese2, W. G. Hartley3, J. Annis2 +1285 more•Institutions (156)
TL;DR: In this article, 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), is presented.
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.
161 citations
TL;DR: In this article, a multi-messenger measurement of the Hubble constant was performed using the binary-black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES).
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 $H_0$.
158 citations
University College London1, Rhodes University2, Fermilab3, Sao Paulo State University4, Autonomous University of Madrid5, University of Portsmouth6, University of Cambridge7, Carnegie Institution for Science8, University of Pennsylvania9, Institut d'Astrophysique de Paris10, Stanford University11, University of São Paulo12, University of Illinois at Urbana–Champaign13, IFAE14, Sun Yat-sen University15, Texas A&M University16, Indian Institute of Technology, Hyderabad17, University of Arizona18, California Institute of Technology19, University of Manchester20, University of Michigan21, Ludwig Maximilian University of Munich22, ETH Zurich23, University of California, Santa Cruz24, Ohio State University25, Max Planck Society26, Harvard University27, Australian Astronomical Observatory28, Argonne National Laboratory29, University of Geneva30, University of Sussex31, Universidade Federal do Rio Grande do Sul32, Brookhaven National Laboratory33, University of Southampton34, State University of Campinas35, Oak Ridge National Laboratory36
TL;DR: In this paper, the authors presented the results of a study at the Ohio State University's Center for Cosmology and Astro-Particle Physics (CSOP) at the University of Illinois at Urbana-Champaign.
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]
156 citations
University of Arizona1, Max Planck Society2, Ludwig Maximilian University of Munich3, SLAC National Accelerator Laboratory4, Stanford University5, University of Pennsylvania6, Princeton University7, Brookhaven National Laboratory8, Fermilab9, Stony Brook University10, Santa Cruz Institute for Particle Physics11, University of Sussex12, University of Michigan13, University College London14, ETH Zurich15, Carnegie Mellon University16, Ohio State University17, California Institute of Technology18, University of California, Riverside19, Brandeis University20, University of Edinburgh21, Rhodes University22, Institute of Cosmology and Gravitation, University of Portsmouth23, University of Manchester24, National Center for Supercomputing Applications25, University of Illinois at Urbana–Champaign26, IFAE27, Spanish National Research Council28, University of Chicago29, Autonomous University of Madrid30, University of Cambridge31, Harvard University32, Steward Health Care System33, Australian Astronomical Observatory34, University of São Paulo35, Texas A&M University36, Catalan Institution for Research and Advanced Studies37, University of Southampton38, State University of Campinas39, Oak Ridge National Laboratory40, Argonne National Laboratory41
TL;DR: In this paper, the authors 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.
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.
154 citations
TL;DR: In this article, the authors derived analytic upper limits on the velocity-independent DM-baryon scattering cross section by translating the upper bound on the lowest mass of halos inferred to host satellites into a characteristic cutoff scale in the linear matter power spectrum.
Abstract: Alternatives to the cold, collisionless dark matter (DM) paradigm in which DM behaves as a collisional fluid generically suppress small-scale structure. Herein we use the observed population of Milky Way (MW) satellite galaxies to constrain the collisional nature of DM, focusing on DM-baryon scattering. We first derive analytic upper limits on the velocity-independent DM-baryon scattering cross section by translating the upper bound on the lowest mass of halos inferred to host satellites into a characteristic cutoff scale in the linear matter power spectrum. We then confirm and improve these results through a detailed probabilistic inference of the MW satellite population that marginalizes over relevant astrophysical uncertainties. This yields $95\%$ confidence upper limits on the DM-baryon scattering cross section of $2\times10^{-29}\ \rm{cm}^2$ ($6\times 10^{-27}\ \rm{cm}^2$) for DM particle masses $m_\chi$ of~$10\ \rm{keV}$ ($10\ \rm{GeV}$); these limits scale as $m_\chi^{1/4}$ for $m_\chi \ll 1\ \rm{GeV}$ and $m_\chi$ for~$m_\chi \gg 1\ \rm{GeV}$. This analysis improves upon cosmological bounds derived from cosmic-microwave-background anisotropy measurements by multiple orders of magnitude over a wide range of DM masses, excluding regions of parameter space previously unexplored by other methods, including direct-detection experiments. Our work reveals a mapping between DM-baryon scattering and other alternative DM models, and we discuss the implications of our results for warm and fuzzy DM scenarios.
115 citations
TL;DR: Combined results from these probes derive constraints on the equation of state, w, of dark energy and its energy density in the Universe, demonstrating the potential power of large multiprobe photometric surveys and paving the way for order of magnitude advances in constraints on properties ofdark energy and cosmology over the next decade.
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.
107 citations
Posted Content•
Lawrence Berkeley National Laboratory1, École Polytechnique Fédérale de Lausanne2, Yale University3, University of Rochester4, University of Portsmouth5, National Tsing Hua University6, Aix-Marseille University7, Harvard University8, University of Arizona9, Durham University10, Universidad de Guanajuato11, CFA Institute12, Argonne National Laboratory13, Ohio State University14, University of California, Santa Cruz15, National Autonomous University of Mexico16, IFAE17, Tsinghua University18, University of Pittsburgh19, University of Waterloo20, IAC21, Ohio University22, University of Michigan23, Stanford University24, Shanghai Jiao Tong University25
TL;DR: The status of the DESI and its plans and opportunities for the coming decade are discussed in this paper, with a focus on wide field spectroscopy and the future of the instrument.
Abstract: We present the status of the Dark Energy Spectroscopic Instrument (DESI) and its plans and opportunities for the coming decade. DESI construction and its initial five years of operations are an approved experiment of the US Department of Energy and is summarized here as context for the Astro2020 panel. Beyond 2025, DESI will require new funding to continue operations. We expect that DESI will remain one of the world's best facilities for wide-field spectroscopy throughout the decade. More about the DESI instrument and survey can be found at this https URL.
98 citations
TL;DR: In this article, the authors proposed a new approach to solve the problem of energy efficiency in the context of energy-efficient wireless sensor networks, which is based on the Langley PITT PACC Postdoctoral fellowship.
Abstract: DOE [DE-SC0015975]; Sloan Foundation [FG-2016-6443]; NSF [AST-1211889]; U.S. Department of Energy [DE-AC02-76SF00515]; Samuel P. Langley PITT PACC Postdoctoral Fellowship; Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]
Posted Content•
TL;DR: Drlica-Wagner et al. as discussed by the authors summarized the science case for studying the fundamental physics of dark matter with LSST and discussed the ways that LSST will complement other experiments to strengthen our understanding of the fundamental characteristics of darkmatter.
Abstract: Author(s): Drlica-Wagner, Alex; Mao, Yao-Yuan; Adhikari, Susmita; Armstrong, Robert; Banerjee, Arka; Banik, Nilanjan; Bechtol, Keith; Bird, Simeon; Boddy, Kimberly K; Bonaca, Ana; Bovy, Jo; Buckley, Matthew R; Bulbul, Esra; Chang, Chihway; Chapline, George; Cohen-Tanugi, Johann; Cuoco, Alessandro; Cyr-Racine, Francis-Yan; Dawson, William A; Rivero, Ana Diaz; Dvorkin, Cora; Erkal, Denis; Fassnacht, Christopher D; Garcia-Bellido, Juan; Giannotti, Maurizio; Gluscevic, Vera; Golovich, Nathan; Hendel, David; Hezaveh, Yashar D; Horiuchi, Shunsaku; Jee, M James; Kaplinghat, Manoj; Keeton, Charles R; Koposov, Sergey E; Lam, Casey Y; Li, Ting S; Lu, Jessica R; Mandelbaum, Rachel; McDermott, Samuel D; McNanna, Mitch; Medford, Michael; Meyer, Manuel; Marc, Moniez; Murgia, Simona; Nadler, Ethan O; Necib, Lina; Nuss, Eric; Pace, Andrew B; Peter, Annika HG; Polin, Daniel A; Prescod-Weinstein, Chanda; Read, Justin I; Rosenfeld, Rogerio; Shipp, Nora; Simon, Joshua D; Slatyer, Tracy R; Straniero, Oscar; Strigari, Louis E; Tollerud, Erik; Tyson, J Anthony; Wang, Mei-Yu; Wechsler, Risa H; Wittman, David; Yu, Hai-Bo; Zaharijas, Gabrijela; Ali-Haimoud, Yacine; Annis, James; Birrer, Simon; Biswas, Rahul; Blazek, Jonathan; Brooks, Alyson M; Buckley-Geer, Elizabeth; Caputo, Regina; Charles, Eric; Digel, Seth; Dodelson, Scott; Flaugher, Brenna; Frieman, Joshua; Gawiser, Eric; Hearin, Andrew P; Hložek, Renee; Jain, Bhuvnesh; Jeltema, Tesla E; Koushiappas, Savvas M; Lisanti, Mariangela | Abstract: Astrophysical and cosmological observations currently provide the only robust, empirical measurements of dark matter. Future observations with Large Synoptic Survey Telescope (LSST) will provide necessary guidance for the experimental dark matter program. This white paper represents a community effort to summarize the science case for studying the fundamental physics of dark matter with LSST. We discuss how LSST will inform our understanding of the fundamental properties of dark matter, such as particle mass, self-interaction strength, non-gravitational couplings to the Standard Model, and compact object abundances. Additionally, we discuss the ways that LSST will complement other experiments to strengthen our understanding of the fundamental characteristics of dark matter. More information on the LSST dark matter effort can be found at https://lsstdarkmatter.github.io/ .
TL;DR: In this article, the authors proposed a method to use the Langley PITT PACC Postdoctoral Fellowship for post-doctoral research in the field of energy-efficient wireless sensor networks.
Abstract: U.S. Department of Energy [DE-AC02-76SF00515]; NSF [AST-1211889]; Samuel P. Langley PITT PACC Postdoctoral Fellowship; Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]
INAF1, University of Arizona2, University of California, Riverside3, Fermilab4, University of Michigan5, Stanford University6, SLAC National Accelerator Laboratory7, Santa Cruz Institute for Particle Physics8, University of Sussex9, Stony Brook University10, Carnegie Mellon University11, Ludwig Maximilian University of Munich12, Max Planck Society13, University College London14, Rhodes University15, Institute of Cosmology and Gravitation, University of Portsmouth16, National Center for Supercomputing Applications17, University of Illinois at Urbana–Champaign18, IFAE19, Spanish National Research Council20, Steward Health Care System21, California Institute of Technology22, University of Chicago23, Autonomous University of Madrid24, ETH Zurich25, Ohio State University26, Harvard University27, Australian Astronomical Observatory28, University of São Paulo29, University of Pennsylvania30, Texas A&M University31, Catalan Institution for Research and Advanced Studies32, Brookhaven National Laboratory33, University of Southampton34, Brandeis University35, State University of Campinas36, Oak Ridge National Laboratory37
TL;DR: In this paper, the authors derived cosmological constraints from the abundance and weak-lensing signal of clusters of richness in the red-shift range of the Sloan Digital Sky Survey (SDSS).
Abstract: We perform the first blind analysis of cluster abundance data. Specifically, we derive cosmological constraints from the abundance and weak-lensing signal of \redmapper\ clusters of richness $\lambda\geq 20$ in the redshift range $z\in[0.1,0.3]$ as measured in the Sloan Digital Sky Survey (SDSS). We simultaneously fit for cosmological parameters and the richness--mass relation of the clusters. For a flat $\Lambda$CDM cosmological model with massive neutrinos, we find $S_8 \equiv \sigma_{8}(\Omega_m/0.3)^{0.5}=0.79^{+0.05}_{-0.04}$. This value is both consistent and competitive with that derived from cluster catalogues selected in different wavelengths. Our result is also consistent with the combined probes analyses by the Dark Energy Survey (DES) and the Kilo-Degree Survey (KiDS), and with the Cosmic Microwave Background (CMB) anisotropies as measured by \planck. We demonstrate that the cosmological posteriors are robust against variation of the richness--mass relation model and to systematics associated with the calibration of the selection function. In combination with Baryon Acoustic Oscillation (BAO) data and Big-Bang Nucleosynthesis (BBN) data, we constrain the Hubble rate to be $h=0.66\pm 0.02$, independent of the CMB. Future work aimed at improving our understanding of the scatter of the richness--mass relation has the potential to significantly improve the precision of our cosmological posteriors. The methods described in this work were developed for use in the forthcoming analysis of cluster abundances in the DES. Our SDSS analysis constitutes the first part of a staged-unblinding analysis of the full DES data set.
TL;DR: In this paper, the authors derived analytic upper limits on the velocity-independent DM-baryon scattering cross section by translating the upper bound on the lowest mass of halos inferred to host satellites into a characteristic cutoff scale in the linear matter power spectrum.
Abstract: Alternatives to the cold, collisionless dark matter (DM) paradigm in which DM behaves as a collisional fluid generically suppress small-scale structure. Herein we use the observed population of Milky Way (MW) satellite galaxies to constrain the collisional nature of DM, focusing on DM-baryon scattering. We first derive analytic upper limits on the velocity-independent DM-baryon scattering cross section by translating the upper bound on the lowest mass of halos inferred to host satellites into a characteristic cutoff scale in the linear matter power spectrum. We then confirm and improve these results through a detailed probabilistic inference of the MW satellite population that marginalizes over relevant astrophysical uncertainties. This yields $95\%$ confidence upper limits on the DM-baryon scattering cross section of $2\times10^{-29}\ \rm{cm}^2$ ($6\times 10^{-27}\ \rm{cm}^2$) for DM particle masses $m_\chi$ of~$10\ \rm{keV}$ ($10\ \rm{GeV}$); these limits scale as $m_\chi^{1/4}$ for $m_\chi \ll 1\ \rm{GeV}$ and $m_\chi$ for~$m_\chi \gg 1\ \rm{GeV}$. This analysis improves upon cosmological bounds derived from cosmic-microwave-background anisotropy measurements by multiple orders of magnitude over a wide range of DM masses, excluding regions of parameter space previously unexplored by other methods, including direct-detection experiments. Our work reveals a mapping between DM-baryon scattering and other alternative DM models, and we discuss the implications of our results for warm and fuzzy DM scenarios.
University of Cambridge1, Carnegie Mellon University2, Macquarie University3, University of Sydney4, Lowell Observatory5, University of New South Wales6, Carnegie Institution for Science7, University of Chicago8, Fermilab9, Rutgers University10, University of Pittsburgh11, Yale University12, Texas A&M University13, Australian National University14, University of Surrey15, Swinburne University of Technology16, University of Wisconsin-Madison17, Kapteyn Astronomical Institute18, Monash University19, SLAC National Accelerator Laboratory20, Stanford University21
TL;DR: The Southern Stellar Stream Spectroscopy Survey (S⁵) as mentioned in this paper is an on-going program to map the kinematics and chemistry of stellar streams in the Southern Hemisphere.
Abstract: We introduce the Southern Stellar Stream Spectroscopy Survey (S⁵), an on-going program to map the kinematics and chemistry of stellar streams in the Southern Hemisphere. The initial focus of S⁵ has been spectroscopic observations of recently identified streams within the footprint of the Dark Energy Survey (DES), with the eventual goal of surveying streams across the entire southern sky. Stellar streams are composed of material that has been tidally striped from dwarf galaxies and globular clusters and hence are excellent dynamical probes of the gravitational potential of the Milky Way, as well as providing a detailed snapshot of its accretion history. Observing with the 3.9-m Anglo-Australian Telescope’s 2-degree-Field fibre positioner and AAOmega spectrograph, and combining the precise photometry of DES DR1 with the superb proper motions from Gaia DR2, allows us to conduct an efficient spectroscopic survey to map these stellar streams. So far S⁵ has mapped 9 DES streams and 3 streams outside of DES; the former are the first spectroscopic observations of these recently discovered streams. In addition to the stream survey, we use spare fibres to undertake a Milky Way halo survey and a low-redshift galaxy survey. This paper presents an overview of the S⁵ program, describing the scientific motivation for the survey, target selection, observation strategy, data reduction and survey validation. Finally, we describe early science results on stellar streams and Milky Way halo stars drawn from the survey. Updates on S⁵, including future public data releases, can be found at http://s5collab.github.io.
Abstract: We develop a comprehensive and flexible model for the connection between satellite galaxies and dark matter subhalos in dark matter-only zoom-in simulations of Milky Way (MW)--mass host halos. We systematically identify the physical and numerical uncertainties in the galaxy--halo connection and simulations underlying our method, including (i) the influence of host halo properties; (ii) the relationship between satellite luminosities and subhalo properties, including the effects of reionization; (iii) the relationship between satellite and subhalo locations; (iv) the relationship between satellite sizes and subhalo properties, including the effects of tidal stripping; (v) satellite and subhalo disruption due to baryonic effects; and (vi) artificial subhalo disruption and orphan satellites. To illustrate our approach, we fit this model to the luminosity distribution of both classical MW satellites and those discovered in the Sloan Digital Sky Survey by performing realistic mock observations that depend on the luminosity, size, and distance of our predicted satellites, and we infer the total satellite population that will be probed by upcoming surveys. We argue that galaxy size and surface brightness modeling will play a key role in interpreting current and future observations, as the expected number of observable satellites depends sensitively on their surface brightness distribution.
TL;DR: Korytov et al. as discussed by the authors proposed cosmoDC2, a large synthetic galaxy catalog designed to support precision dark energy science with the Large Synoptic Survey Telescope (LSST).
Abstract: Author(s): Korytov, Danila; Hearin, Andrew; Kovacs, Eve; Larsen, Patricia; Rangel, Esteban; Hollowed, Joseph; Benson, Andrew J; Heitmann, Katrin; Mao, Yao-Yuan; Bahmanyar, Anita; Chang, Chihway; Campbell, Duncan; DeRose, Joseph; Finkel, Hal; Frontiere, Nicholas; Gawiser, Eric; Habib, Salman; Joachimi, Benjamin; Lanusse, Francois; Li, Nan; Mandelbaum, Rachel; Morrison, Christopher; Newman, Jeffrey A; Pope, Adrian; Rykoff, Eli; Simet, Melanie; To, Chun-Hao; Vikraman, Vinu; Wechsler, Risa H; White, Martin; Collaboration, LSST Dark Energy Sci | Abstract: This paper introduces cosmoDC2, a large synthetic galaxy catalog designed to support precision dark energy science with the Large Synoptic Survey Telescope (LSST). CosmoDC2 is the starting point for the second data challenge (DC2) carried out by the LSST Dark Energy Science Collaboration (LSST DESC). The catalog is based on a trillion-particle, 4.225 Gpc^3 box cosmological N-body simulation, the `Outer Rim' run. It covers 440 deg^2 of sky area to a redshift of z=3 and is complete to a magnitude depth of 28 in the r-band. Each galaxy is characterized by a multitude of properties including stellar mass, morphology, spectral energy distributions, broadband filter magnitudes, host halo information and weak lensing shear. The size and complexity of cosmoDC2 requires an efficient catalog generation methodology; our approach is based on a new hybrid technique that combines data-driven empirical approaches with semi-analytic galaxy modeling. A wide range of observation-based validation tests has been implemented to ensure that cosmoDC2 enables the science goals of the planned LSST DESC DC2 analyses. This paper also represents the official release of the cosmoDC2 data set, including an efficient reader that facilitates interaction with the data.
University of Pennsylvania1, Stanford University2, University of Chicago3, Cornell University4, Argonne National Laboratory5, Ludwig Maximilian University of Munich6, University of KwaZulu-Natal7, Brookhaven National Laboratory8, University of Arizona9, Max Planck Society10, Ohio State University11, Princeton University12, Fermilab13, Pierre-and-Marie-Curie University14, Institut d'Astrophysique de Paris15, University of Toronto16, University of Missouri–Kansas City17, University College London18, University of Illinois at Urbana–Champaign19, IFAE20, Spanish National Research Council21, Indian Institute of Technology, Hyderabad22, California Institute of Technology23, University of Michigan24, Autonomous University of Madrid25, University of Melbourne26, ETH Zurich27, University of California, Santa Cruz28, Florida State University29, Rutgers University30, Harvard University31, Lawrence Berkeley National Laboratory32, Macquarie University33, University of São Paulo34, Texas A&M University35, Pontifical Catholic University of Chile36, University of Milan37, Yale University38, Haverford College39, Ames Research Center40, University of Colorado Boulder41, University of Sussex42, University of Southampton43, Brandeis University44, State University of Campinas45, Oak Ridge National Laboratory46, University of Portsmouth47, Goddard Space Flight Center48
TL;DR: In this article, the authors measured the splashback feature in clusters selected via the SZ effect in data from the South Pole Telescope SZ survey and the Atacama Cosmology Telescope Polarimeter survey.
Abstract: We present a detection of the splashback feature around galaxy clusters selected using the Sunyaev–Zel’dovich (SZ) signal. Recent measurements of the splashback feature around optically selected galaxy clusters have found that the splashback radius, rsp, is smaller than predicted by N-body simulations. A possible explanation for this discrepancy is that rsp inferred from the observed radial distribution of galaxies is affected by selection effects related to the optical cluster-finding algorithms. We test this possibility by measuring the splashback feature in clusters selected via the SZ effect in data from the South Pole Telescope SZ survey and the Atacama Cosmology Telescope Polarimeter survey. The measurement is accomplished by correlating these cluster samples with galaxies detected in the Dark Energy Survey Year 3 data. The SZ observable used to select clusters in this analysis is expected to have a tighter correlation with halo mass and to be more immune to projection effects and aperture-induced biases, potentially ameliorating causes of systematic error for optically selected clusters. We find that the measured rsp for SZ-selected clusters is consistent with the expectations from simulations, although the small number of SZ-selected clusters makes a precise comparison difficult. In agreement with previous work, when using optically selected redMaPPer clusters with similar mass and redshift distributions, rsp is ∼2σ smaller than in the simulations. These results motivate detailed investigations of selection biases in optically selected cluster catalogues and exploration of the splashback feature around larger samples of SZ-selected clusters. Additionally, we investigate trends in the galaxy profile and splashback feature as a function of galaxy colour, finding that blue galaxies have profiles close to a power law with no discernible splashback feature, which is consistent with them being on their first infall into the cluster.
Stanford University1, SLAC National Accelerator Laboratory2, Spanish National Research Council3, University of Pennsylvania4, Ohio State University5, California Institute of Technology6, IFAE7, Catalan Institution for Research and Advanced Studies8, Duke University9, Fermilab10, Institute of Cosmology and Gravitation, University of Portsmouth11, University of Wisconsin-Madison12, University of Manchester13, University College London14, University of Illinois at Urbana–Champaign15, National Center for Supercomputing Applications16, Indian Institute of Technology, Hyderabad17, University of Chicago18, Steward Health Care System19, University of Michigan20, Autonomous University of Madrid21, ETH Zurich22, Santa Cruz Institute for Particle Physics23, Smithsonian Institution24, Macquarie University25, University of São Paulo26, Texas A&M University27, Princeton University28, University of Southampton29, Brandeis University30, State University of Campinas31, Oak Ridge National Laboratory32, Argonne National Laboratory33
TL;DR: In this paper, the authors present a 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.
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.
TL;DR: In this article, the authors proposed a method to use the Langley PITT PACC Postdoctoral Fellowship for postdoctoral research at the US Department of Energy (USDOE).
Abstract: US Department of Energy [DE-AC02-76SF00515]; NSF [AST-1211889]; DOE [DE-SC0015975]; Sloan Foundation [FG-2016-6443]; Samuel P. Langley PITT PACC Postdoctoral Fellowship; Office of Science of the US Department of Energy [DE-AC02-05CH11231]
Fermilab1, University of California, Santa Cruz2, University of Arizona3, Carnegie Mellon University4, University of Michigan5, University of Sussex6, Stanford University7, Ludwig Maximilian University of Munich8, Stony Brook University9, Liverpool John Moores University10, University of KwaZulu-Natal11, Max Planck Society12, University of Edinburgh13, Uppsala University14, Lancaster University15, University of Oxford16, University of Porto17, University of Portsmouth18, University of Wisconsin-Madison19, Pierre-and-Marie-Curie University20, Institut d'Astrophysique de Paris21, University College London22, University of Illinois at Urbana–Champaign23, IFAE24, Spanish National Research Council25, Indian Institute of Technology, Hyderabad26, Autonomous University of Madrid27, ETH Zurich28, Ohio State University29, Macquarie University30, University of São Paulo31, Texas A&M University32, Princeton University33, University of Southampton34, Brandeis University35, Oak Ridge National Laboratory36, Argonne National Laboratory37
TL;DR: In this paper, the authors present the results of the work of the International Journal of Cosmology and Astro-Particle Physics at the University of Illinois at Urbana-Champaign.
Abstract: UK Science and Technology Facilities Council [ST/P000252/1, ST/N504452/1]; U. S. Department of Energy [DE-AC02-76SF00515]; Chandra Award [GO8-19101A]; 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]; European Union; CERCA program of the Generalitat de Catalunya; European Research Council under the European Union [240672, 291329, 306478]; Australian Research Council Centre of Excellence for All-sky Astrophysics (CAAS-TRO) [CE110001020]; U.S. Department of Energy, Office of Science, Office of High Energy Physics [DE-AC02-07CH11359]; [DE-SC0010107]; [DE-SC0013541]
TL;DR: In this paper, the authors developed an empirical method to characterize the impact of projection effects on redMaPPer cluster catalogues and used numerical simulations to validate their method and illustrate its robustness.
Abstract: The cosmological utility of galaxy cluster catalogues is primarily limited by our ability to calibrate the relation between halo mass and observable mass proxies such as cluster richness, X-ray luminosity or the Sunyaev-Zeldovich signal Projection effects are a particularly pernicious systematic effect that can impact observable mass proxies; structure along the line of sight can both bias and increase the scatter of the observable mass proxies used in cluster abundance studies In this work, we develop an empirical method to characterize the impact of projection effects on redMaPPer cluster catalogues We use numerical simulations to validate our method and illustrate its robustness We demonstrate that modeling of projection effects is a necessary component for cluster abundance studies capable of reaching $\approx 5\%$ mass calibration uncertainties (eg the Dark Energy Survey Year 1 sample) Specifically, ignoring the impact of projection effects in the observable--mass relation --- ie marginalizing over a log-normal model only --- biases the posterior of the cluster normalization condition $S_8 \equiv \sigma_8 (\Omega_{\rm m}/03)^{1/2}$ by $\Delta S_8 =005$, more than twice the uncertainty in the posterior for such an analysis
TL;DR: Abdelalla et al. as mentioned in this paper performed a joint analysis of the auto and cross-correlations between three cosmic fields: the galaxy density field, the galaxy weak lensing shear field, and the cosmic microwave background (CMB) weak-lingualing convergence field using roughly 1300 sq. deg. of overlapping optical imaging data from first year observations of the Dark Energy Survey and millimeter-wave observations from both the South Pole Telescope Sunyaev-Zel'dovich survey and Planck.
Abstract: Author(s): Abbott, TMC; Abdalla, FB; Alarcon, A; Allam, S; Annis, J; Avila, S; Aylor, K; Banerji, M; Banik, N; Baxter, EJ; Bechtol, K; Becker, MR; Benson, BA; Bernstein, GM; Bertin, E; Bianchini, F; Blazek, J; Bleem, LE; Bridle, SL; Brooks, D; Buckley-Geer, E; Burke, DL; Carlstrom, JE; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Castander, FJ; Cawthon, R; Chang, C; Chang, CL; Cho, H-M; Choi, A; Chown, R; Crawford, TM; Crites, AT; Crocce, M; Cunha, CE; D'Andrea, CB; da Costa, LN; Davis, C; de Haan, T; DeRose, J; Desai, S; De Vicente, J; Diehl, HT; Dietrich, JP; Dobbs, MA; Dodelson, S; Doel, P; Drlica-Wagner, A; Eifler, TF; Elvin-Poole, J; Everett, WB; Flaugher, B; Fosalba, P; Friedrich, O; Frieman, J; Garcia-Bellido, J; Gatti, M; Gaztanaga, E; George, EM; Gerdes, DW; Giannantonio, T; Gruen, D; Gruendl, RA; Gschwend, J; Gutierrez, G; Halverson, NW; Harrington, NL; Hartley, WG; Holder, GP; Hollowood, DL; Holzapfel, WL; Honscheid, K; Hou, Z; Hoyle, B; Hrubes, JD; Huterer, D; Jain, B; James, DJ; Jarvis, M; Jeltema, T; Johnson, MWG; Johnson, MD; Kent, S | Abstract: We perform a joint analysis of the auto and cross-correlations between three cosmic fields: the galaxy density field, the galaxy weak lensing shear field, and the cosmic microwave background (CMB) weak lensing convergence field. These three fields are measured using roughly 1300 sq. deg. of overlapping optical imaging data from first year observations of the Dark Energy Survey and millimeter-wave observations of the CMB from both the South Pole Telescope Sunyaev-Zel'dovich survey and Planck. We present cosmological constraints from the joint analysis of the two-point correlation functions between galaxy density and galaxy shear with CMB lensing. We test for consistency between these measurements and the DES-only two-point function measurements, finding no evidence for inconsistency in the context of flat $\Lambda$CDM cosmological models. Performing a joint analysis of five of the possible correlation functions between these fields (excluding only the CMB lensing autospectrum) yields $S_{8}\equiv \sigma_8\sqrt{\Omega_{\rm m}/0.3} = 0.782^{+0.019}_{-0.025}$ and $\Omega_{\rm m}=0.260^{+0.029}_{-0.019}$. We test for consistency between these five correlation function measurements and the Planck-only measurement of the CMB lensing autospectrum, again finding no evidence for inconsistency in the context of flat $\Lambda$CDM models. Combining constraints from all six two-point functions yields $S_{8}=0.776^{+0.014}_{-0.021}$ and $\Omega_{\rm m}= 0.271^{+0.022}_{-0.016}$. These results provide a powerful test and confirmation of the results from the first year DES joint-probes analysis.
TL;DR: In this article, a model of the galaxy-halo connection was combined with newly derived observational selection functions based on searches for satellites in photometric surveys over nearly the entire high Galactic latitude sky.
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.
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TL;DR: A suite of 18 synthetic sky catalogs designed to support science analysis of galaxies in the DES Y1 data is presented in this paper, which is tuned to match the observed evolution of galaxy counts at different luminosities and the spatial clustering of the galaxy population.
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.
University of Chicago1, Fermilab2, University of Wisconsin-Madison3, Stanford University4, Carnegie Mellon University5, Texas A&M University6, University of Arizona7, Carnegie Institution for Science8, University of Paris9, University College London10, University of Illinois at Urbana–Champaign11, Indian Institute of Technology, Hyderabad12, California Institute of Technology13, University of California, Santa Cruz14, Autonomous University of Madrid15, Spanish National Research Council16, Ohio State University17, Harvard University18, Lowell Observatory19, Macquarie University20, Princeton University21, University of Michigan22, University of Southampton23, Oak Ridge National Laboratory24
TL;DR: In this paper, a systematic search for ultra-faint Milky Way satellite galaxies using data from the Dark Energy Survey (DES) and Pan-STARRS1 (PS1) is reported.
Abstract: We report the results of a systematic search for ultra-faint Milky Way satellite galaxies using data from the Dark Energy Survey (DES) and Pan-STARRS1 (PS1). Together, DES and PS1 provide multi-band photometry in optical/near-infrared wavelengths over ~80% of the sky. Our search for satellite galaxies targets ~25,000 deg$^2$ of the high-Galactic-latitude sky reaching a 10$\sigma$ point-source depth of $\gtrsim$ 22.5 mag in the $g$ and $r$ bands. While satellite galaxy searches have been performed independently on DES and PS1 before, this is the first time that a self-consistent search is performed across both data sets. We do not detect any new high-significance satellite galaxy candidates, while recovering the majority of satellites previously detected in surveys of comparable depth. We characterize the sensitivity of our search using a large set of simulated satellites injected into the survey data. We use these simulations to derive both analytic and machine-learning models that accurately predict the detectability of Milky Way satellites as a function of their distance, size, luminosity, and location on the sky. To demonstrate the utility of this observational selection function, we calculate the luminosity function of Milky Way satellite galaxies, assuming that the known population of satellite galaxies is representative of the underlying distribution. We provide access to our observational selection function to facilitate comparisons with cosmological models of galaxy formation and evolution.
TL;DR: In this article, a machine learning method for the reconstruction of the undistorted images of background sources in strongly lensed systems is presented, which treats the source as a pixelated image and utilizes the Recurrent Inference Machine (RIM) to iteratively reconstruct the background source given a lens model.
Abstract: We present a machine learning method for the reconstruction of the undistorted images of background sources in strongly lensed systems. This method treats the source as a pixelated image and utilizes the Recurrent Inference Machine (RIM) to iteratively reconstruct the background source given a lens model. Our architecture learns to minimize the likelihood of the model parameters (source pixels) given the data using the physical forward model (ray tracing simulations) while implicitly learning the prior of the source structure from the training data. This results in better performance compared to linear inversion methods, where the prior information is limited to the 2-point covariance of the source pixels approximated with a Gaussian form, and often specified in a relatively arbitrary manner. We combine our source reconstruction network with a convolutional neural network that predicts the parameters of the mass distribution in the lensing galaxies directly from telescope images, allowing a fully automated reconstruction of the background source images and the foreground mass distribution.
Stanford University1, Autonomous University of Madrid2, Spanish National Research Council3, University of La Laguna4, University of California, Berkeley5, INAF6, University of Bologna7, SLAC National Accelerator Laboratory8, École Polytechnique Fédérale de Lausanne9, Chinese Academy of Sciences10, University of Edinburgh11, University of Western Australia12
TL;DR: The UNIT $N$-body cosmological simulations project as discussed by the authors was designed to provide precise predictions for nonlinear statistics of the galaxy distribution, including redshift space distortions and cosmic voids.
Abstract: We present the UNIT $N$-body cosmological simulations project, designed to provide precise predictions for nonlinear statistics of the galaxy distribution. We focus on characterizing statistics relevant to emission line and luminous red galaxies in the current and upcoming generation of galaxy surveys. We use a suite of precise particle mesh simulations (FastPM) as well as with full $N$-body calculations with a mass resolution of $\sim 1.2\times10^9\,h^{-1}$M$_{\odot}$ to investigate the recently suggested technique of Angulo & Pontzen 2016 to suppress the variance of cosmological simulations We study redshift space distortions, cosmic voids, higher order statistics from $z=2$ down to $z=0$. We find that both two- and three-point statistics are unbiased. Over the scales of interest for baryon acoustic oscillations and redshift-space distortions, we find that the variance is greatly reduced in the two-point statistics and in the cross correlation between halos and cosmic voids, but is not reduced significantly for the three-point statistics. We demonstrate that the accuracy of the two-point correlation function for a galaxy survey with effective volume of 20 ($h^{-1}$Gpc)$^3$ is improved by about a factor of 40, indicating that two pairs of simulations with a volume of 1 ($h^{-1}$Gpc)$^3$ lead to the equivalent variance of $\sim$150 such simulations. The $N$-body simulations presented here thus provide an effective survey volume of about seven times the effective survey volume of DESI or Euclid. The data from this project, including dark matter fields, halo catalogues, and their clustering statistics, are publicly available at this http URL
TL;DR: In this paper, the authors consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts or based on spectroscopic data (as with the HETDEX survey of Lyα emitters).
Abstract: Line-intensity mapping is an emerging field of observational work, with strong potential to fit into a larger effort to probe large-scale structure and small-scale astrophysical phenomena using multiple complementary tracers. Taking full advantage of such complementarity means, in part, undertaking line-intensity surveys with galaxy surveys in mind. We consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts (as in COSMOS) or based on spectroscopic data (as with the HETDEX survey of Lyα emitters). We find that obtaining σ_z (1+z) ≲ 0.003 accuracy in redshifts and ≳10^(−4) sources per Mpc^3 with spectroscopic redshift determination should enable a CO-galaxy cross spectrum detection significance at least twice that of the CO auto spectrum. Either a future targeted spectroscopic survey or a blind survey like HETDEX may be able to meet both of these requirements.