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Lattices in three dimensions are oft studied from the ``reciprocal space'' perspective of diffraction. Today, the full lattice of a crystal can often be inferred from direct-space information about three sets of non-parallel lattice planes.…

Materials Science · Physics 2007-05-23 W. Qin , P. Fraundorf

Widefield surveys of the sky probe many clustered scalar fields -- such as galaxy counts, lensing potential, gas pressure, etc. -- that are sensitive to different cosmological and astrophysical processes. Our ability to constrain such…

The standard model of cosmology ($\Lambda$CDM) is facing a serious crisis caused by the inconsistencies in the measurements of some fundamental cosmological parameters (Hubble constant $H_{0}$ and cosmic curvature parameter $\Omega_{k}$ for…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-05 Savita Gahlaut

We present exact analytic formulae for the eclipse of a star described by quadratic or nonlinear limb darkening. In the limit that the planet radius is less than a tenth of the stellar radius, we show that the exact lightcurve can be well…

Astrophysics · Physics 2009-11-07 Kaisey Mandel , Eric Agol

The {\it Linear Point} (LP), defined as the midpoint between the BAO peak and the associated left dip of the two-point correlation function (2PCF), $\xi(s)$, is proposed as a new standard ruler which is insensitive to nonlinear effects. In…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-02 Mengfan He , Cheng Zhao , Huanyuan Shan

Langevin Monte Carlo (LMC) is a popular Bayesian sampling method. For the log-concave distribution function, the method converges exponentially fast, up to a controllable discretization error. However, the method requires the evaluation of…

Machine Learning · Statistics 2025-03-07 Zhiyan Ding , Qin Li

Here we present a number of improvements to weak lensing 3D power spectrum analysis, 3D cosmic shear, that uses the shape and redshift information of every galaxy to constrain cosmological parameters. We show how photometric redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 T. D. Kitching , A. F. Heavens , L. Miller

21cm tomography opens a window to directly study astrophysics and fundamental physics of early epochs in our Universe's history, the Epoch of Reionisation (EoR) and Cosmic Dawn (CD). Summary statistics such as the power spectrum omit…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 S. Neutsch , C. Heneka , M. Brüggen

We explore linear and non-linear dimensionality reduction techniques for statistical inference of parameters in cosmology. Given the importance of compressing the increasingly complex data vectors used in cosmology, we address questions…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-12 Minsu Park , Marco Gatti , Bhuvnesh Jain

Our goal in this paper is to test some popular dark matter models by Ly-alpha forest in QSO spectra. Recent observations of the size and velocity of Ly-alpha forest clouds have indicated that the Ly-alpha absorption is probably not given by…

Astrophysics · Physics 2009-10-28 Hongguang BI , Jian GE , Li-Zhi FANG

A q-query locally testable code (LTC) is an error correcting code that can be tested by a randomized algorithm that reads at most q symbols from the given word. An important question is whether there exist LTCs that have the ccc-property:…

Computational Complexity · Computer Science 2010-12-14 Irit Dinur , Tali Kaufman

This work presents a new method to compute time and wavelength dependent center-to-limb brightness distributions for Classical Cepheids. Our model atmospheres are based on second-order accurate 1-D hydrodynamic calculations, performed in…

Astrophysics · Physics 2009-11-07 M. Marengo , D. D. Sasselov , M. Karovska , C. Papaliolios , J. T. Armstrong

In this paper we study the sensitivity of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project to the determination of cosmological parameters, employing the Monte Carlo Markov Chains (MCMC) method. For comparison,…

Astrophysics · Physics 2010-05-12 Hong Li , Jun-Qing Xia , Zuhui Fan , Xinmin Zhang

We extend 21CMMC, a Monte Carlo Markov Chain sampler of 3D reionisation simulations, to perform parameter estimation directly on 3D light-cones of the cosmic 21cm signal. This brings theoretical analysis closer to the tomographic 21-cm…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Bradley Greig , Andrei Mesinger

In these Lectures I review possible constraints on particle physics models, obtained by means of combining the results of collider measurements with astrophysical data. I emphasize the theoretical-model dependence of these results. I…

High Energy Physics - Phenomenology · Physics 2017-08-23 Nikolaos E. Mavromatos

Comparing clustering of differently biased tracers of the dark matter distribution offers the opportunity to reduce the cosmic variance error in the measurement of certain cosmological parameters. We develop a formalism that includes bias…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-08 H. Gil-Marín , C. Wagner , L. Verde , R. Jimenez , A. F. Heavens

Obtaining accurately calibrated redshift distributions of photometric samples is one of the great challenges in photometric surveys like LSST, Euclid, HSC, KiDS, and DES. We present an inference methodology that combines the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-09 M. M. Rau , C. B. Morrison , S. J. Schmidt , S. Wilson , R. Mandelbaum , Y. Y. Mao

A simple transit model is described along with tests of this model against published results for 4 exoplanet systems (Kepler-1, 2, 8, and 77). Data from the Kepler mission are used. The Markov Chain Monte Carlo (MCMC) method is applied to…

Earth and Planetary Astrophysics · Physics 2017-06-28 Yi Ji , Timothy Banks , Edwin Budding , Michael Rhodes

We revisit dark matter (DM) capture in celestial objects, including the impact of multiple scattering, and obtain updated constraints on the DM-proton cross section using observations of white dwarfs. Considering a general form for the…

High Energy Physics - Phenomenology · Physics 2024-06-13 Basudeb Dasgupta , Aritra Gupta , Anupam Ray

Model stellar atmospheres are fundamental tools for understanding stellar observations from interferometry, microlensing, eclipsing binaries and planetary transits. However, the calculations also include assumptions, such as the geometry of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Hilding R. Neilson , John B. Lester