David Alonso
A5057299715- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Superconducting and THz Device Technology
- Computational Physics and Python Applications
- History and Developments in Astronomy
- Black Holes and Theoretical Physics
- Solar and Space Plasma Dynamics
- Astrophysics and Star Formation Studies
- Statistical and numerical algorithms
- Distributed and Parallel Computing Systems
- Statistical Methods and Inference
- Ecology and Vegetation Dynamics Studies
- Relativity and Gravitational Theory
- Diverse Aspects of Tourism Research
- Educational theories and practices
University of Oxford
2015-2024
Science Oxford
2021-2023
Laboratoire Lorrain de Recherche en Informatique et ses Applications
2023
Universitat Politècnica de València
2022
Cardiff University
2018-2021
Consejo Superior de Investigaciones Científicas
2010-2013
Universidad Autónoma de Madrid
2010-2013
(Abridged) We describe here the most ambitious survey currently planned in optical, Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST have unique capability faint time domain. The design is driven four main themes: probing dark energy matter, taking an inventory Solar System, exploring transient optical sky, mapping Milky Way. wide-field ground-based system sited at Cerro Pach\'{o}n northern Chile. telescope 8.4 m...
The Simons Observatory (SO) is a new cosmic microwave background experiment being built on Cerro Toco in Chile, due to begin observations the early 2020s. We describe scientific goals of experiment, motivate design, and forecast its performance. SO will measure temperature polarization anisotropy six frequency bands: 27, 39, 93, 145, 225 280 GHz. initial configuration have three small-aperture 0.5-m telescopes (SATs) one large-aperture 6-m telescope (LAT), with total 60,000 cryogenic...
We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from Atacama Cosmology Telescope, using data taken 2013-2016 at 98 150 GHz. The cover more than 17,000 deg$^2$, deepest 600 deg$^2$ with noise levels below 10 $\mu$K-arcmin. use power spectrum derived almost 6,000 these to constrain cosmology. ACT enable a measurement angular scale features in both divergence-like anisotropy, tracing velocity density last-scattering. From one...
We present the science case, reference design, and project plan for Stage-4 ground-based cosmic microwave background experiment CMB-S4.
This book lays out the scientific goals to be addressed by next-generation ground-based cosmic microwave background experiment, CMB-S4, envisioned consist of dedicated telescopes at South Pole, high Chilean Atacama plateau and possibly a northern hemisphere site, all equipped with new superconducting cameras. CMB-S4 will dramatically advance cosmological studies crossing critical thresholds in search for B-mode polarization signature primordial gravitational waves, determination number...
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 present the temperature and polarization angular power spectra of CMB measured by Atacama Cosmology Telescope (ACT) from 5400 deg$^2$ 2013-2016 survey, which covers $>$15000 at 98 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related this, show numerous checks for systematic error done before unblinding. Using likelihood cosmological constrain secondary sources anisotropy foreground emission, derive "CMB-only" spectrum that extends...
The pseudo-Cℓ is an algorithm for estimating the angular power and cross-power spectra that very fast in realistic cases also nearly optimal. can be extended to deal with contaminant deprojection E/B purification, therefore applied a wide variety of scenarios interest current future cosmological observations. This paper presents namaster, public, validated, accurate, easy-to-use software package that, first time, provides unified framework compute any pair spin-0 or spin-2 fields,...
Abstract The Einstein Telescope (ET), the European project for a third-generation gravitational-wave detector, has reference configuration based on triangular shape consisting of three nested detectors with 10 km arms, where each detector 'xylophone' made an interferometer tuned toward high frequencies, and low frequencies working at cryogenic temperature. Here, we examine scientific perspectives under possible variations this design. We perform detailed evaluation science case single...
We present a numerical code to simulate maps of Galactic emission in intensity and polarization at microwave frequencies, aiding the design cosmic background experiments. This python builds on existing efforts sky by providing an easy-to-use interface is based publicly available data from WMAP (Wilkinson Microwave Anisotropy Probe) Planck satellite missions. synchrotron, thermal dust, free–free anomalous over whole sky, addition background, include set alternative prescriptions for frequency...
Abstract CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding origin evolution universe. Among science cases pursued with CMB-S4, quest for detecting primordial gravitational waves is a central driver experimental design. This work details development forecasting framework that includes power-spectrum-based semianalytic projection tool, targeted explicitly toward...
Observational cosmology in the next decade will rely on probes of distribution matter redshift range between $0<z<3$ to elucidate nature dark and energy. In this range, galaxy formation is known have a significant impact observables such as two-point correlations shapes positions, altering their amplitude scale dependence beyond expected statistical uncertainty upcoming experiments at separations under 10 Mpc. Successful extraction information regime thus requires, very least, unbiased...
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...
Abstract We present a new, all-sky quasar catalog, Quaia, that samples the largest comoving volume of any existing spectroscopic sample. The catalog draws on 6,649,162 candidates identified by Gaia mission have redshift estimates from space observatory’s low-resolution blue photometer/red photometer spectra. This initial sample is highly homogeneous and complete, but has low purity, 18% even bright ( G < 20.0) confirmed quasars discrepant (∣Δ z /(1 + )∣ > 0.2) compared to those Sloan...
Abstract We present a formalism to extract the angular power spectrum of fields sampled at finite number points with arbitrary positions — common situation for several catalog-based astrophysical probes through simple extension standard pseudo- C ℓ algorithm. A key complication in this case is need handle shot noise component associated discrete mask which, sparse catalogs, can lead strong coupling between very different scales. show that problem be solved easily by estimating contribution...
HI intensity mapping (IM) is a novel technique capable of the large-scale structure Universe in three dimensions and delivering exquisite constraints on cosmology, by using as biased tracer dark matter density field.This achieved measuring redshifted 21cm line over sky range redshifts without requirement to resolve individual galaxies.In this chapter, we investigate potential SKA1 deliver maps broad frequencies substantial fraction sky.By pinning down baryon acoustic oscillation redshift...
The next generation of surveys will greatly improve our knowledge cosmological gravity. In this paper we focus on how Stage IV photometric redshift surveys, including weak lensing and multiple tracers the matter distribution radio experiments combined with measurements cosmic microwave background lead to precision constraints deviations from general relativity. We use a broad subclass Horndeski scalar-tensor theories forecast accuracy which be able determine these their degeneracies other...
We make use of a large set fast simulations an intensity mapping experiment with characteristics similar to those expected the Square Kilometre Array (SKA) in order study viability and limits blind foreground subtraction techniques. In particular, we consider different approaches: polynomial fitting, principal component analysis (PCA) independent (ICA). review motivations algorithms for three methods, show that they can all be described, using same mathematical framework, as approaches...
Multiple tracers of the cosmic density field, with different bias, number and luminosity evolution, can be used to measure large-scale properties Universe. We show how an optimal combination detect general-relativistic effects in observed sources. forecast for detectability these effects, as well measurements primordial non-Gaussianity lensing magnification current upcoming structure experiments. In particular we quantify significance detections short term experiments such Dark Energy Survey...
The Large Synoptic Survey Telescope (LSST) Dark Energy Science Collaboration (DESC) will use five cosmological probes: galaxy clusters, large scale structure, supernovae, strong lensing, and weak lensing. This Requirements Document (SRD) quantifies the expected dark energy constraining power of these probes individually together, with conservative assumptions about analysis methodology follow-up observational resources based on our current understanding evolution within field in coming...
Future surveys of large-scale structure will be able to measure perturbations on the scale cosmological horizon, and so could potentially probe a number novel relativistic effects that are negligibly small sub-horizon scales. These leave distinctive signatures in power spectra clustering observables and, if measurable, would open new window cosmology. We quantify size detectability for most relevant future experiments: spectroscopic photometric galaxy redshift surveys, intensity mapping...