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Determining the redshift distribution $n(z)$ of galaxy samples is essential for several cosmological probes including weak lensing. For imaging surveys, this is usually done using photometric redshifts estimated on an object-by-object…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-31 Jörg Herbel , Tomasz Kacprzak , Adam Amara , Alexandre Refregier , Claudio Bruderer , Andrina Nicola

We explore the enhanced self-calibration of photometric galaxy redshift distributions, $n(z)$, through the combination of up to six two-point functions. Our $\rm 3\times2pt$ configuration is comprised of photometric shear, spectroscopic…

We present a field-based approach to the analysis of cosmic shear data to infer jointly cosmological parameters and the dark matter distribution. This forward modelling approach samples the cosmological parameters and the initial matter…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-17 Natalia Porqueres , Alan Heavens , Daniel Mortlock , Guilhem Lavaux

The parameters of a linear compartment model are usually estimated from experimental input-output data. A problem arises when infinitely many parameter values can yield the same result; such a model is called unidentifiable. In this case,…

Combinatorics · Mathematics 2016-03-08 Jasmijn A. Baaijens , Jan Draisma

Motivated by the current constraints on the epoch of reionisation from recent cosmic microwave background observations, ionising background measurements of star-forming galaxies, and low redshifts line-of-sight probes, we propose a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-10 Marian Douspis , Nabila Aghanim , Stéphane Ilić , Mathieu Langer

We consider distributed estimation of the inverse covariance matrix, also called the concentration or precision matrix, in Gaussian graphical models. Traditional centralized estimation often requires global inference of the covariance…

Machine Learning · Statistics 2015-06-15 Zhaoshi Meng , Dennis Wei , Ami Wiesel , Alfred O. Hero

We perform a general optimization of the parameters in the Multilevel Monte Carlo (MLMC) discretization hierarchy based on uniform discretization methods with general approximation orders and computational costs. We optimize hierarchies…

Numerical Analysis · Mathematics 2015-06-09 Abdul Lateef Haji Ali , Fabio Nobile , Erik von Schwerin , Raul Tempone

We investigate how the constraints on cosmological and astrophysical parameters ($\Omega_{\rm m}$, $\sigma_{8}$, $A_{\rm SN1}$, $A_{\rm SN2}$) vary when exploiting information from multiple fields in cosmology. We make use of a…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-05 Sambatra Andrianomena , Sultan Hassan

We present predictions for cosmological parameter constraints from combined measurements of second- and third-order statistics of cosmic shear. We define the generalized third-order aperture mass statistics <M_ap^3> and show that it…

Astrophysics · Physics 2008-11-26 Martin Kilbinger , Peter Schneider

We advocate for a new paradigm of cosmological likelihood-based inference, leveraging recent developments in machine learning and its underlying technology, to accelerate Bayesian inference in high-dimensional settings. Specifically, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-06 Davide Piras , Alicja Polanska , Alessio Spurio Mancini , Matthew A. Price , Jason D. McEwen

Pruning methods have recently grown in popularity as an effective way to reduce the size and computational complexity of deep neural networks. Large numbers of parameters can be removed from trained models with little discernible loss in…

Machine Learning · Computer Science 2024-01-18 Tim Whitaker , Darrell Whitley

Photometric large scale structure (LSS) surveys probe the largest volumes in the Universe, but are inevitably limited by systematic uncertainties. Imperfect photometric calibration leads to biases in our measurements of the density fields…

Analytical expressions for covariances of weak lensing statistics related to the aperture mass $\Map$ are derived for realistic survey geometries such as SNAP for a range of smoothing angles and redshift bins. We incorporate the…

Astrophysics · Physics 2009-11-10 Dipak Munshi , Patrick Valageas

An observational program focused on the high redshift ($2<z<6$) Universe has the opportunity to dramatically improve over upcoming LSS and CMB surveys on measurements of both the standard cosmological model and its extensions. Using a…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-04 Noah Sailer , Emanuele Castorina , Simone Ferraro , Martin White

Accurate photometric redshifts are a lynchpin for many future experiments to pin down the cosmological model and for studies of galaxy evolution. In this study, a novel sparse regression framework for photometric redshift estimation is…

Instrumentation and Methods for Astrophysics · Physics 2025-06-03 Ibrahim A. Almosallam , Sam N. Lindsay , Matt J. Jarvis , Stephen J. Roberts

Photometric galaxy surveys constitute a powerful cosmological probe but rely on the accurate characterization of their redshift distributions using only broadband imaging, and can be very sensitive to incomplete or biased priors used for…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-30 Alex Alarcon , Carles Sánchez , Gary M. Bernstein , Enrique Gaztañaga

For known gravitational lens systems the redshift distribution of the lenses is compared with theoretical expectations for $10^{4}$~Friedmann-Lema\^\i tre~cosmological models, which more than cover the range of possible cases. The…

Astrophysics · Physics 2011-05-23 Phillip Helbig , Rainer Kayser

Cosmological parameter estimation from forthcoming experiments promise to reach much greater precision than current constraints. As statistical errors shrink, the required control over systematic errors increases. Therefore, models or…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 José Luis Bernal , Nicola Bellomo , Alvise Raccanelli , Licia Verde

Cosmological observations usually map our present-day past light cone. However, it is also possible to compare different past light cones. This is the concept behind the redshift drift, a model-independent probe of fundamental cosmology. In…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-12 C. S. Alves , A. C. O. Leite , C. J. A. P. Martins , J. G. B. Matos , T. A. Silva