A5033956680- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Computational Physics and Python Applications
- Gamma-ray bursts and supernovae
- Blind Source Separation Techniques
- Solar and Space Plasma Dynamics
- Climate variability and models
- Advanced Thermodynamics and Statistical Mechanics
- Neutrino Physics Research
- Face and Expression Recognition
- Space Science and Extraterrestrial Life
- Gaussian Processes and Bayesian Inference
- CCD and CMOS Imaging Sensors
- Bayesian Methods and Mixture Models
- Advanced Fluorescence Microscopy Techniques
- Quantum Mechanics and Applications
- Relativity and Gravitational Theory
- Voice and Speech Disorders
Institute for Advanced Study
2016-2024
Partners In Care
2024
Institut d'Astrophysique Spatiale
2019
University of California, Berkeley
2014-2017
Lawrence Berkeley National Laboratory
2014-2017
University of Cambridge
2012-2013
Max Planck Institute for Biological Cybernetics
2008
Max Planck Society
2008
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...
Given the importance of future large scale structure surveys for delivering new cosmological information, it is crucial to reliably predict their observables. The Effective Field Theory Large Scale Structures (EFTofLSS) provides a manifestly convergent perturbative scheme compute clustering dark matter in weakly nonlinear regime an expansion $k/k_{\rm NL}$, where $k$ wavenumber interest and $k_{\rm NL}$ associated scale. It has been recently shown that EFTofLSS matches $1\%$ level power...
The lensing convergence measurable with future CMB surveys like CMB-S4 will be highly correlated the clustering observed by deep photometric large scale structure (LSS) such as LSST, cross-correlation coefficient high 95%. This enable use of sample variance cancellation techniques to determine cosmological parameters, and measurements break parameter degeneracies. Assuming sky overlap between we show that a joint analysis LSST can yield very tight constraints on matter amplitude...
The authors test the perturbative halo bias model, of central relevance for cosmological large scale structure, at field level which allows a direct comparison with simulations. It turns out that model errors can be significantly reduced by this method is particular observables require precise estimate large-scale potential.
As confusion with lensing B modes begins to limit experiments that search for primordial B-mode polarization, robust methods delensing the cosmic microwave background (CMB) polarization sky are becoming increasingly important. We investigate in detail possibility of CMB infrared (CIB), emission from dusty star-forming galaxies is an excellent tracer signal, order improve constraints on tensor-to-scalar ratio $r$. find maps CIB, such as current Planck satellite at 545 GHz, can be used remove...
The Probe of Inflation and Cosmic Origins (PICO) is a proposed probe-scale space mission consisting an imaging polarimeter operating in frequency bands between 20 800 GHz. We describe the science achievable by PICO, which has sensitivity equivalent to more than 3300 Planck missions, technical implementation, schedule cost.
Motivated by recent developments in perturbative calculations of the nonlinear evolution large-scale structure, we present an iterative algorithm to reconstruct initial conditions a given volume starting from dark matter distribution real space. In our algorithm, objects are first moved back iteratively along estimated potential gradients, with progressively reduced smoothing scale, until nearly uniform catalog is obtained. The linear density then as divergence cumulative displacement,...
As galaxy surveys begin to measure the imprint of baryonic acoustic oscillations (BAO) on large-scale structure at sub-percent level, reconstruction techniques that reduce contamination from nonlinear clustering become increasingly important. Inverting continuity equation, we propose an Eulerian growth-shift algorithm does not require displacement any objects, which is needed for standard Lagrangian BAO algorithm. In real-space DM-only simulations yields 95% signal-to-noise obtained...
The usual fluid equations describing the large-scale evolution of mass density in universe can be written as local density, velocity divergence, and potential fields. As a result, perturbative expansion small fluctuations, usually terms convolutions Fourier space, series products these fields evaluated at same location configuration space. Based on this, we establish new method to numerically evaluate 1-loop power spectrum (i.e., transform 2-point correlation function) with one-dimensional...
CMB and lensing reconstruction power spectra are powerful probes of cosmology. However, they correlated, since the lensed, is constructed using multipoles. We perform a full analysis auto- cross-covariances, including polarization minimum-variance estimators, compare with simulations idealized future CMB-S4 observations. Covariances sourced by fluctuations in unlensed instrumental noise can largely be removed realization-dependent subtraction noise, leaving relatively simple covariance model...
Clustering of large-scale structure provides significant cosmological information through the power spectrum density perturbations. Additional can be gained from higher-order statistics like bispectrum, especially to break degeneracy between linear halo bias ${b}_{1}$ and amplitude fluctuations ${\ensuremath{\sigma}}_{8}$. We propose new simple, computationally inexpensive bispectrum that are near optimal for specific applications determination. Corresponding Legendre decomposition nonlinear...
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...
Creating accurate and low-noise covariance matrices represents a formidable challenge in modern-day cosmology. We present formalism to compress arbitrary observables into small number of bins by projection model-specific subspace that minimizes the prior-averaged log-likelihood error. The lower dimensionality leads dramatic reduction matrix noise, significantly reducing mocks need be computed. Given theory model, set priors, simple model covariance, our method works using singular value...
Abstract We develop an analytical forward model based on perturbation theory to predict the redshift-space galaxy overdensity at field level given a realization of initial conditions. find that residual noise between and simulated density has power spectrum is white large scales, with size comparable shot noise. In mildly nonlinear regime, we see k 2 μ correction spectrum, corresponding larger along line sight smaller scales. The parametric form this been predicted theoretical grounds...
Gravitational lensing provides a significant source of cosmological information in modern CMB parameter analyses. It is measured both the power spectrum and trispectrum temperature fluctuations. These observables are often treated as independent, although they determined from same map this impossible. In paper, we perform rigorous analysis covariance between We find two dominant contributions coming from: (i) correlations disconnected noise bias measurement sample variance spectrum; (ii)...
The rapidly improving precision of measurements gravitational lensing the Cosmic Microwave Background (CMB) also requires a corresponding increase in theoretical modeling. A commonly made approximation is to model CMB deflection angle or potential as Gaussian random field. In this paper, however, we analytically quantify influence non-Gaussianity large-scale structure lenses, arising from nonlinear formation, on measurements. particular, evaluating impact non-zero bispectrum relevant...
The Probe of Inflation and Cosmic Origins (PICO) is an imaging polarimeter that will scan the sky for 5 years in 21 frequency bands spread between 799 GHz. It produce full-sky surveys intensity polarization with a final combined-map noise level 0.87 $\mu$K arcmin required specifications, equivalent to 3300 Planck missions, our current best-estimate would have 0.61 (6400 missions). PICO either determine energy scale inflation by detecting tensor scalar ratio at $r=5\times 10^{-4}~(5\sigma)$,...
As a major source of cosmological information, galaxy clustering is susceptible to long-wavelength density and tidal fluctuations. These long modes modulate the growth expansion rate local structures, shifting them in both amplitude scale. effects are often named dilation effects, respectively. In particular shifts baryon acoustic oscillation (BAO) peak breaks assumption Alcock-Paczynski (AP) test. This cannot be removed with reconstruction techniques because effect originates from outside...
We study the matter bispectrum of large-scale structure by comparing different perturbative and phenomenological models with measurements from $N$-body simulations obtained a modal estimator. Using shape amplitude correlators, we directly compare simulated data theoretical over full three-dimensional domain bispectrum, for redshifts scales. review investigate main methods in literature that predict one-loop bispectrum: standard perturbation theory, effective field resummed Lagrangian...
Future Baryon Acoustic Oscillation surveys aim at observing galaxy clustering over a wide range of redshift and populations great precision, reaching tenths percent, in order to detect any deviation dark energy from the lambda cold matter (|$\rm {\Lambda CDM}$|) model. We utilize set paired quasi-N-body FastPM simulations that were designed mitigate sample variance effect on BAO feature evaluated systematics as precisely ∼0.01 per cent. report anisotropic scale shifts before after density...
Modeling the large-scale structure of universe on nonlinear scales has potential to substantially increase science return upcoming surveys by increasing number modes available for model comparisons. One way achieve this is perturbatively. Unfortunately, involves high-dimensional loop integrals that are cumbersome evaluate. Trying simplify this, we show how two-loop (next-to-next-to-leading order) corrections density power spectrum can be reduced low-dimensional, radial integrals. Many those...