William R. Coulton
A5074837816- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Dark Matter and Cosmic Phenomena
- Scientific Research and Discoveries
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Computational Physics and Python Applications
- Statistical and numerical algorithms
- Black Holes and Theoretical Physics
- Blind Source Separation Techniques
- Superconducting and THz Device Technology
- Adaptive optics and wavefront sensing
- Advanced Mathematical Theories and Applications
- Gamma-ray bursts and supernovae
- Statistical Mechanics and Entropy
- Advanced Thermodynamics and Statistical Mechanics
- Neutrino Physics Research
- Neural Networks and Applications
- demographic modeling and climate adaptation
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
Netherlands Institute for Radio Astronomy
2024-2025
Flatiron Institute
2022-2024
Flatiron Health (United States)
2022-2024
Princeton University
2017-2024
University of Cambridge
2019-2024
The University of Tokyo
2021-2022
Kavli Institute for the Physics and Mathematics of the Universe
2021-2022
University of Oxford
2013
In this paper, we describe the optical imaging data processing pipeline developed for Subaru Telescope's Hyper Suprime-Cam (HSC) instrument. The HSC Pipeline builds on prototype being by Large Synoptic Survey Data Management system, adding customizations HSC, large-scale capabilities, and novel algorithms that have since been reincorporated into LSST codebase. While designed primarily to reduce Strategic Program (SSP) data, it is also recommended reducing general-observer data. includes high...
We present cosmological constraints from a gravitational lensing mass map covering 9400 sq. deg. reconstructed CMB measurements made by the Atacama Cosmology Telescope (ACT) 2017 to 2021. In combination with BAO (from SDSS and 6dF), we obtain amplitude of matter fluctuations $\sigma_8 = 0.819 \pm 0.015$ at 1.8% precision, $S_8\equiv\sigma_8({\Omega_{\rm m}}/0.3)^{0.5}=0.840\pm0.028$ Hubble constant $H_0= (68.3 1.1)\, \text{km}\,\text{s}^{-1}\,\text{Mpc}^{-1}$ 1.6% precision. A joint...
We present new measurements of cosmic microwave background (CMB) lensing over $9400$ sq. deg. the sky. These are derived from Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) CMB dataset, which consists five seasons ACT temperature and polarization observations. determine amplitude power spectrum at $2.3\%$ precision ($43\sigma$ significance) using a novel pipeline that minimizes sensitivity to foregrounds noise properties. To ensure our results robust, we analyze an extensive set null...
Observations of the millimeter sky contain valuable information on a number signals, including blackbody cosmic microwave background (CMB), Galactic emissions, and Compton-y distortion due to thermal Sunyaev-Zel'dovich (tSZ) effect. Extracting new insight into cosmological astrophysical questions often requires combining multiwavelength observations spectrally isolate one component. In this work, we present arc-minute-resolution map, which traces out line-of-sight-integrated electron...
Abstract We investigate the impact and mitigation of extragalactic foregrounds for cosmic microwave background (CMB) lensing power spectrum analysis Atacama Cosmology Telescope (ACT) data release 6 (DR6) data. Two independent sky simulations are used to test a range strategies. demonstrate that finding then subtracting point sources, models clusters, using profile bias-hardened estimator together reduce fractional biases well below statistical uncertainties, with inferred amplitude, A lens ,...
Abstract We present and characterize the catalog of galaxy shape measurements that will be used for cosmological weak lensing in Wide layer first year Hyper Suprime-Cam (HSC) survey. The covers an area 136.9 deg2 split into six fields, with a mean i-band seeing 0${^{\prime\prime}_{.}}$58 5σ point-source depth i ∼ 26. Given conservative selection criteria first-year science, excellent image quality results unweighted weighted source number densities 24.6 21.8 arcmin−2, respectively. define...
Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable any realistic terrestrial experiment. Theoretical insights into inflationary era and its observational probes may therefore shed unique light on physical laws underlying our universe. This white paper describes current theoretical understanding of era, with focus statistical properties primordial fluctuations. In particular, we survey targets for three important signatures...
Primordial non-Gaussianity (PNG) is one of the most powerful probes early Universe and measurements large scale structure have potential to transform our understanding this area. However relating late time primordial perturbations challenging due non-linear processes that govern evolution Universe. To help address issue we release a suite N-body simulations containing four types PNG: \textsc{quijote-png}. These were designed augment \textsc{quijote} explored impact various cosmological...
Abstract We investigate how much can be learnt about four types of primordial non-Gaussianity (PNG) from small-scale measurements the halo field. Using quijote-png simulations, we quantify information content accessible with power spectrum monopole and quadrupole, matter spectrum, halo–matter cross bispectrum monopole. This analysis is first to include small, nonlinear scales, up <?CDATA ${k}_{\max }=0.5\,{\rm{h}}\,{\mathrm{Mpc}}^{-1}$?> <mml:math...
What would a parity-violating universe look like? We present numerical and theoretical study of mirror asymmetries in the late universe, using new suite $N$-body simulations: quijote-odd. These feature initial conditions, injected via simple ansatz for imaginary primordial trispectrum evolved into nonlinear regime. find that realization-averaged power spectrum, bispectrum, halo mass function, matter PDF are not affected by our modifications to deep regime, which we argue arises from...
ABSTRACT We present cosmological constraints derived from peak counts, minimum and the angular power spectrum of Subaru Hyper Suprime-Cam first-year (HSC Y1) weak lensing shear catalogue. Weak counts contain non-Gaussian information hence are complementary to conventional two-point statistics in constraining cosmology. In this work, we forward-model three summary their dependence on cosmology, using a suite N-body simulations tailored HSC Y1 data. investigate systematic astrophysical effects...
We explore the effect of massive neutrinos on weak lensing shear bispectrum using Cosmological Massive Neutrino Simulations [1]. find that primary is to suppress amplitude with limited shape. The suppression a factor two greater than small scale power-spectrum. For an LSST-like survey observes half sky five tomographic redshift bins, we constraining power three cosmological parameters: sum neutrino mass ∑ mν, matter density Ωm and primordial fluctuations As. Bispectrum measurements alone...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
The Cosmology and Astrophysics with MachinE Learning Simulations (CAMELS) project was developed to combine cosmology astrophysics through thousands of cosmological hydrodynamic simulations machine learning. CAMELS contains 4,233 simulations, 2,049 N-body 2,184 state-of-the-art that sample a vast volume in parameter space. In this paper we present the public data release, describing characteristics variety products generated from them, including halo, subhalo, galaxy, void catalogues, power...
Abstract Primordial non-Gaussianity of the local type induces a strong scale-dependent bias on clustering halos in late-time Universe. This signature is particularly promising to provide constraints parameter f NL from galaxy surveys, as amplitude grows with scale and becomes important large, linear scales. However, there well-known degeneracy between real prize, parameter, (non-Gaussian) assembly i.e., halo formation history-dependent contribution signal, which could seriously compromise...
The observed UV continuum slope of star-forming galaxies is strongly affected by the presence dust. Its observation then a potentially valuable diagnostic dust attenuation, particularly at high redshift where other diagnostics are currently inaccessible. Interpreting in context attenuation often achieved assuming empirically calibrated Meurer et al. relation. Implicit this relation assumption an intrinsic (β = −2.23). However, results from numerical simulations suggest that slopes...
Massive cosmic neutrinos change the structure formation history by suppressing perturbations on small scales. Weak lensing data from galaxy surveys probe evolution and thereby can be used to constrain total mass of three active neutrinos. However, much information is at scales where dynamics are nonlinear. Traditional approaches with second-order statistics thus fail fully extract in field. In this paper, we study constraints neutrino sum using peak counts, a statistic which captures...
The hot dense environment of the early universe is known to have produced large numbers baryons, photons, and neutrinos. These extreme conditions may also other long-lived species, including new light particles (such as axions or sterile neutrinos) gravitational waves. effects any such relics can be observed through their unique imprint in cosmic microwave background (CMB), large-scale structure, primordial element abundances, are important determining initial universe. We argue that future...
The large-scale clustering of matter is impacted by baryonic physics, particularly AGN feedback. Modelling or mitigating this impact will be essential for making full use upcoming measurements cosmic shear and other structure probes. We study effects on the bispectrum, using from a selection state-of-the-art hydrodynamical simulations: IllustrisTNG, Illustris, EAGLE, BAHAMAS. identify low-redshift enhancement peaking at $k\sim 3h\,{\rm Mpc}^{-1}$, that present in several simulations, discuss...
This paper explores methods for constructing low multipole temperature and polarisation likelihoods from maps of the cosmic microwave background anisotropies that have complex noise properties partial sky coverage. We use Planck 2018 High Frequency Instrument (HFI) updated SRoll2 to test our methods. present three likelihood approximations based on quadratic cross spectrum estimators: (i) a variant simulation-based (SimBaL) techniques used in legacy papers produce EE likelihood; (ii)...
Recent advances in cosmological observations have provided an unprecedented opportunity to investigate the distribution of baryons relative underlying matter. In this work, we robustly show that gas is much more extended than dark matter at 40$\sigma$ and amount baryonic feedback $z \lesssim 1$ strongly disfavors low-feedback models such as state-of-the-art hydrodynamical simulation IllustrisTNG compared with high-feedback original Illustris simulation. This has important implications for...
ABSTRACT Searches for primordial non-Gaussianity in cosmological perturbations are a key means of revealing novel physics. However, robustly extracting signatures from non-linear scales the late-time Universe is an open problem. In this paper, we apply k-Nearest Neighbour cumulative distribution functions, kNN-CDFs, to quijote-png simulations explore sensitivity kNN-CDFs non-Gaussianity. An interesting result that halo samples with $M_\mathrm{ h}\langle 10^{14}$ M$_\odot$ $h^{-1}$, respond...
Statistics that capture the directional dependence of baryon distribution in cosmic web enable unique tests cosmology and astrophysical feedback. We use constrained oriented stacking thermal Sunyaev-Zel'dovich (tSZ) maps to measure anisotropic hot gas $2.5-40$ Mpc away from galaxy clusters embedded massive filaments superclusters. The cluster selection orientation (at a scale $\sim15$ Mpc) Dark Energy Survey (DES) Year 3 data, while expanded tSZ Atacama Cosmology Telescope Data Release 6...
Analysis of microwave sky signals, such as the cosmic background, often requires component separation using multifrequency methods, whereby different signals are isolated according to their frequency behaviors. Many so-called blind internal linear combination (ILC), make minimal assumptions about spatial distribution signal or contaminants, and only assume knowledge dependence signal. The ILC produces a minimum-variance measured maps. In case Gaussian, statistically isotropic fields, this is...