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Fast Radio Bursts (hereafter FRBs) can be used in cosmology by studying the Dispersion Measure (hereafter DM) as a function of redshift. The large scale structure of matter distribution is regarded as a major error budget for such…

宇宙学与河外天体物理 · 物理学 2022-07-27 Chenghao Zhu , Jiajun Zhang

With WMAP putting the phenomenological standard model of cosmology on a strong footing, one can look forward to mining the cosmic microwave background (CMB) for fundamental physics with higher sensitivity and on smaller scales. Future CMB…

天体物理学 · 物理学 2015-06-24 Manoj Kaplinghat

In this paper we obtain constraints on the cosmological density parameters, \Omega_m and \Omega_b, by comparing the preliminary measurement of the QSO power spectrum from the two degree field QSO redshift survey with results from an…

天体物理学 · 物理学 2009-11-07 Kazuhiro Yamamoto

In this study, we use late-time probes, such as well-localized fast radio bursts (FRBs), baryon acoustic oscillations (BAO), supernovae (SNe), and cosmic chronometers (CC) to constrain cosmological parameters through a model-independent…

Creating accurate and low-noise covariance matrices represents a formidable challenge in modern-day cosmology. We present a formalism to compress arbitrary observables into a small number of bins by projection into a model-specific subspace…

宇宙学与河外天体物理 · 物理学 2021-02-10 Oliver H. E. Philcox , Mikhail M. Ivanov , Matias Zaldarriaga , Marko Simonovic , Marcel Schmittfull

The covariance matrix $\boldsymbol{\Sigma}$ of non-linear clustering statistics that are measured in current and upcoming surveys is of fundamental interest for comparing cosmological theory and data and a crucial ingredient for the…

宇宙学与河外天体物理 · 物理学 2022-04-13 Nicolas Chartier , Benjamin D. Wandelt

We consider a flat cosmological model with a free massless scalar field and the cosmological constant $\Lambda$ in the framework of loop quantum cosmology. The scalar field plays the role of an intrinsic time. We apply the reduced phase…

广义相对论与量子宇宙学 · 物理学 2014-11-20 Jakub Mielczarek , Wlodzimierz Piechocki

Our group has developed a technique that makes use of the observed non-linear relation between the ultraviolet and the X-ray luminosity in quasars to provide an independent measurement of their distances, thus turning quasars into…

宇宙学与河外天体物理 · 物理学 2020-03-05 Elisabeta Lusso

Recent observational progress has led to the establishment of the standard $\Lambda$CDM model for cosmology. This development is based on different cosmological probes that are usually combined through their likelihoods at the latest stage…

宇宙学与河外天体物理 · 物理学 2016-11-23 Andrina Nicola , Alexandre Refregier , Adam Amara

The power spectrum of mass density fluctuations is evaluated from the Mark III and the SFI catalogs of peculiar velocities by a maximum likelihood analysis, using parametric models for the power spectrum and for the errors. The applications…

天体物理学 · 物理学 2007-05-23 Idit Zehavi , Avishai Dekel

In this paper, a parametrization describing the kinematical state of the universe via cosmographic approach is considered, where the minimum input is the assumption of the cosmological principle, i.e. the Friedmann-Robertson-Walker metric.…

宇宙学与河外天体物理 · 物理学 2015-05-19 Lixin Xu , Yuting Wang

These notes are very much work-in-progress and simply intended to showcase, in various degrees of details (and rigour), some of the cosmology calculations that class_sz can do. We describe the class_sz code in C, Python and Jax. Based on…

Context. Explaining the accelerated expansion of the Universe is one of the fundamental challenges in physics today. Cosmography provides information about the evolution of the universe derived from measured distances, assuming only that…

宇宙学与河外天体物理 · 物理学 2016-10-05 Marek Demianski , Ester Piedipalumbo , Disha Sawant , Lorenzo Amati

The possibility of determining cosmological parameters on the basis of a wide set of observational data including the Abell-ACO cluster power spectrum and mass function, peculiar velocities of galaxies, the distribution of Ly-$\alpha$…

天体物理学 · 物理学 2007-05-23 B. Novosyadlyj , R. Durrer , S. Gottloeber , V. N. Lukash , S. Apunevych

In this paper we propose a kernel based COBRA which is a direct approximation of the original COBRA. We propose a novel tuning procedure for original COBRA parameters based on this kernel approximation. We show that our proposed algorithm…

机器学习 · 计算机科学 2022-10-20 Mriganka Basu RoyChowdhury , Arabin K Dey

We present a new method that simultaneously solves for cosmology and galaxy bias on non-linear scales. The method uses the halo model to analytically describe the (non-linear) matter distribution, and the conditional luminosity function…

宇宙学与河外天体物理 · 物理学 2015-06-05 Frank van den Bosch , Surhud More , Marcello Cacciato , Houjun Mo , Xiaohu Yang

We investigate the question of how tightly we can constrain the cosmological parameters by using the ``cosmic inversion'' method in which we directly reconstruct the power spectrum of primordial curvature perturbations, $P(k)$, from the…

天体物理学 · 物理学 2009-10-09 Noriyuki Kogo , Misao Sasaki , Jun'ichi Yokoyama

We build a field level emulator for cosmic structure formation that is accurate in the nonlinear regime. Our emulator consists of two convolutional neural networks trained to output the nonlinear displacements and velocities of N-body…

宇宙学与河外天体物理 · 物理学 2023-08-02 Drew Jamieson , Yin Li , Renan Alves de Oliveira , Francisco Villaescusa-Navarro , Shirley Ho , David N. Spergel

We constrain the parameters describing the kinematical state of the universe using a cosmographic approach, which is fundamental in that it requires a very minimal set of assumptions (namely to specify a metric) and does not rely on the…

宇宙学与河外天体物理 · 物理学 2014-11-20 Vincenzo Vitagliano , Jun-Qing Xia , Stefano Liberati , Matteo Viel

We introduce a noise-aware extension to the parametric maximum-likelihood framework for component separation by modeling correlated $1/f^\alpha$ noise as a harmonic-space power law. This approach addresses a key limitation of existing…

宇宙学与河外天体物理 · 物理学 2025-11-07 Goureesankar Sathyanathan , Josquin Errard , Soumen Basak