A5035813533- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- CCD and CMOS Imaging Sensors
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Pulsars and Gravitational Waves Research
- Remote Sensing in Agriculture
- Astronomical Observations and Instrumentation
- Statistical and numerical algorithms
- Advanced Image Processing Techniques
- Gaussian Processes and Bayesian Inference
- Advanced Vision and Imaging
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Spatial and Panel Data Analysis
- Black Holes and Theoretical Physics
- Impact of Light on Environment and Health
- Computational Physics and Python Applications
University of Edinburgh
2017-2025
UK Astronomy Technology Centre
2017-2024
Royal Observatory
2019-2024
Netherlands Institute for Radio Astronomy
2024
Institute of Astronomy
2023
Scottish Universities Physics Alliance
2019
University of Manchester
2013-2018
University of Oxford
2008-2018
Manchester University
2015
University College London
2011-2013
We use 26×106 galaxies from the Dark Energy Survey (DES) Year 1 shape catalogs over 1321 deg2 of sky to produce most significant measurement cosmic shear in a galaxy survey date. constrain cosmological parameters both flat ΛCDM and wCDM models, while also varying neutrino mass density. These results are shown be robust using two independent catalogs, photo-z calibration methods, analysis pipelines blind analysis. find 3.5% fractional uncertainty on σ8(Ωm/0.3)0.5=0.782+0.027−0.027 at 68%...
We report the discovery of eight new ultra-faint dwarf galaxy candidates in second year optical imaging data from Dark Energy Survey (DES). Six these are detected at high confidence, while two lower-confidence identified regions non-uniform survey coverage. The stellar systems found by three independent automated search techniques and as overdensities stars, consistent with isochrone luminosity function an old metal-poor simple population. faint (Mv > -4.7 mag) span a range physical sizes...
We report the discovery of eight new Milky Way companions in optical imaging data collected during first year Dark Energy Survey (DES). Each system is identified as a statistically significant over-density individual stars consistent with expected isochrone and luminosity function an old metal-poor stellar population. The objects span wide range absolute magnitudes (MV from to ), physical sizes (), heliocentric distances (). Based on low surface brightnesses, large sizes, and/or...
Abstract We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 Square Kilometre Array (SKA1) and science they will enable. highlight three main surveys: medium-deep continuum weak lensing low-redshift spectroscopic HI galaxy survey over 5 000 deg 2 ; wide deep intensity mapping (IM) 20 from $z = 0.35$ 3; deep, high-redshift IM 100 3$ 6. Taken together, these achieve an array important scientific goals: measuring equation state dark energy \sim...
We combine Dark Energy Survey Year 1 clustering and weak lensing data with Baryon Acoustic Oscillations (BAO) Big Bang Nucleosynthesis (BBN) experiments to constrain the Hubble constant. Assuming a flat $\Lambda$CDM model minimal neutrino mass ($\sum m_\nu = 0.06$ eV) we find $H_0=67.2^{+1.2}_{-1.0}$ km/s/Mpc (68% CL). This result is completely independent of constant measurements based on distance ladder, Cosmic Microwave Background (CMB) anisotropies (both temperature polarization), strong...
We describe the creation, content, and validation of Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support upcoming cosmological analyses. The GOLD set is assembled from multiple epochs DES imaging consists calibrated photometric zeropoints, object catalogs, ancillary products - e.g., maps survey depth observing conditions, star-galaxy classification, redshift estimates that are necessary for accurate wide-area catalog ~137 million objects detected coadded...
We constrain the mass–richness scaling relation of redMaPPer galaxy clusters identified in Dark Energy Survey Year 1 data using weak gravitational lensing. split into 4 × 3 bins richness λ and redshift |$z$| for ≥ 20 0.2 ≤ 0.65 measure mean masses these their stacked lensing signal. By modelling as 〈M200m|λ, |$z$|〉 = M0(λ/40)F((1 + |$z$|)/1.35)G, we normalization at 5.0 per cent level, finding M0 [3.081 ± 0.075(stat) 0.133(sys)] · 1014 M⊙ 40 0.35. The recovered index is F 1.356 0.051 (stat)...
We present two galaxy shape catalogues from the Dark Energy Survey Year 1 data set, covering 1500 square degrees with a median redshift of $0.59$. The cover main fields: Stripe 82, and an area overlapping South Pole Telescope survey region. describe our analysis process in particular measurement using independent shear pipelines, METACALIBRATION IM3SHAPE. catalogue uses Gaussian model innovative internal calibration scheme, was applied to $riz$-bands, yielding 34.8M objects. IM3SHAPE...
We present weak lensing shear catalogues for 139 square degrees of data taken during the Science Verification (SV) time new Dark Energy Camera (DECam) being used Survey (DES). describe our object selection, point spread function estimation and measurement procedures using two independent pipelines, im3shape ngmix, which produce 2.12 million 3.44 galaxies, respectively. detail a set null tests measurements find that they pass requirements systematic errors at level necessary science...
ABSTRACT We present and characterize the galaxy shape catalogue from first 3 yr of Dark Energy Survey (DES) observations, over an effective area 4143 deg2 southern sky. describe our data analysis process self-calibrating shear measurement pipeline metacalibration, which builds improves upon used in DES Year 1 several aspects. The weak-lensing consists 100 204 026 galaxies, measured riz bands, resulting a weighted source number density neff = 5.59 gal arcmin−2 corresponding noise σe 0.261....
We measure weak lensing cosmic shear power spectra from the 3-year galaxy catalog of Hyper Suprime-Cam (HSC) Subaru Strategic Program imaging survey. The covers 416 deg2 northern sky, with a mean i-band seeing 0.59 arcsec and an effective number density 15 arcmin−2 within our adopted redshift range. With magnitude limit 24.5 mag, four tomographic bins spanning 0.3≤zph≤1.5 based on photometric redshifts, we obtain high-significance measurement spectra, signal-to-noise ratio approximately 26.4...
We examine the level of agreement between low-redshift weak lensing data and cosmic microwave background using measurements from Canada–France–Hawaii Telescope Lensing Survey (CFHTLenS) Planck+Wilkinson Microwave Anisotropy Probe (WMAP) polarization. perform an independent analysis CFHTLenS six bin tomography results Heymans et al. extend their systematics treatment find cosmological constraints to be relatively robust choice non-linear modelling, extension intrinsic alignment model...
We present results from a study of the photometric redshift performance Dark Energy Survey (DES), using early data Science Verification period observations in late 2012 and 2013 that provided science-quality images for almost 200 sq. deg. at nominal depth survey. assess (photo-z) about 15 000 galaxies with spectroscopic redshifts available other surveys. These are used, different configurations, as calibration sample, photo-z's obtained studied most existing photo-z codes. A weighting method...
We present photometric redshift estimates for galaxies used in the weak lensing analysis of Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based methods -- ANNZ2, BPZ calibrated against BCC-Ufig simulations, SkyNet, and TPZ are analysed. For training, calibration, testing these methods, we construct a catalogue spectroscopically confirmed matched DES SV The performance is evaluated spectroscopic catalogue, focusing on metrics relevant analyses, with...
We present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, in a sequence of challenges for testing methods inferring weak gravitational lensing shear distortions simulated galaxy images. GREAT3 was divided into experiments to test three specific questions, and included space- ground-based data with constant or cosmologically varying fields. The simplest (control) experiment parametric galaxies realistic distribution signal-to-noise, size, ellipticity,...
In this paper, we present results from the weak-lensing shape measurement GRavitational lEnsing Accuracy Testing 2010 (GREAT10) Galaxy Challenge. This marks an order of magnitude step change in level scrutiny employed analysis. We provide descriptions each method tested and include 10 evaluation metrics over 24 simulation branches.
We present the methodology for and detail implementation of Dark Energy Survey (DES) 3x2pt DES Year 1 (Y1) analysis, which combines configuration-space two-point statistics from three different cosmological probes: cosmic shear, galaxy-galaxy lensing, galaxy clustering, using data first year observations. have developed two independent modeling pipelines describe code validation process. derive expressions analytical real-space multi-probe covariances, their with numerical simulations....
The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with goal testing and facilitating development methods for analyzing astronomical images that will be used to measure weak gravitational lensing. This measurement requires extremely precise estimation very small galaxy shape distortions, presence far larger intrinsic shapes distortions due blurring kernel caused by atmosphere, telescope optics, instrumental effects. GREAT3...
We present the methodology for a joint cosmological analysis of weak gravitational lensing from fourth data release ESO Kilo-Degree Survey (KiDS-1000) and galaxy clustering partially overlapping Baryon Oscillation Spectroscopic (BOSS) 2-degree Field Lensing (2dFLenS). Cross-correlations between BOSS 2dFLenS positions source ellipticities have been incorporated into analysis, necessitating development hybrid model non-linear scales that blends perturbative non-perturbative approaches, an...
We use weak-lensing shear measurements to determine the mean mass of optically selected galaxy clusters in Dark Energy Survey Science Verification data. In a blinded analysis, we split sample more than 8,000 redMaPPer into 15 subsets, spanning ranges richness parameter $5 \leq λ\leq 180$ and redshift $0.2 z 0.8$, fit averaged density contrast profiles with model that accounts for seven distinct sources systematic uncertainty: measurement photometric errors; cluster-member contamination;...
We derive cosmological constraints from the probability distribution function (PDF) of evolved large-scale matter density fluctuations. do this by splitting lines sight based on their count tracer galaxies, and measuring both gravitational shear around counts-in-cells in overdense underdense sight, Dark Energy Survey (DES) First Year Sloan Digital Sky (SDSS) data. Our analysis uses a perturbation theory model [O. Friedrich et al., Phys. Rev. D 98, 023508 (2018)] is validated using $N$-body...
We present galaxy-galaxy lensing measurements from 1321 sq. deg. of the Dark Energy Survey (DES) Year 1 (Y1) data. The lens sample consists a selection 660,000 red galaxies with high-precision photometric redshifts, known as redMaGiC, split into five tomographic bins in redshift range 0.15<z<0.9. use two different source samples, obtained Metacalibration (26 million galaxies) and im3shape (18 shear estimation codes, which are four 0.2<z<1.3. perform extensive testing potential systematic...
We present measurements of weak gravitational lensing cosmic shear two-point statistics using Dark Energy Survey Science Verification data. demonstrate that our results are robust to the choice measurement pipeline, either ngmix or im3shape, and statistic, including both real Fourier-space statistics. Our pass a suite null tests for B-mode contamination direct any dependence functions on set 16 observing conditions galaxy properties, such as seeing, airmass, color, magnitude, etc....