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Accurate prediction of rarefied gas flows is important for space vehicle design, particularly in rarefied regimes where the Navier-Stokes equations are no more valid. While the direct simulation Monte Carlo (DSMC) method acts as a numerical…

Fluid Dynamics · Physics 2025-07-01 Joonbeom Kim , Eunji Jun

Recent studies have shown that the cross-correlation coefficient between galaxies and dark matter is very close to unity on scales outside a few virial radii of galaxy halos, independent of the details of how galaxies populate dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Rachel Mandelbaum , Anze Slosar , Tobias Baldauf , Uros Seljak , Christopher M. Hirata , Reiko Nakajima , Reinabelle Reyes , Robert E. Smith

Calibrating the redshift distributions of photometric galaxy samples is essential in weak lensing studies. The self-calibration method combines angular auto- and cross-correlations between galaxies in multiple photometric redshift…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-07 Haojie Xu , Pengjie Zhang , Hui Peng , Yu Yu , Le Zhang , Ji Yao , Jian Qin , Zeyang Sun , Min He , Xiaohu Yang

We investigate the existence and meaning of a preferred length in the large-scale distribution of 60-micron IRAS sources applying three tests to the 2-dimensional distribution on the celestial sphere, involving respectively the rms…

Astrophysics · Physics 2011-05-23 R. Fabbri , V. Natale

We present a new method to estimate three-point correlations in Cosmic Microwave Background maps. Our Fast Fourier Transform based implementation estimates three-point functions using all possible configurations (triangles) at a controlled…

Astrophysics · Physics 2009-11-13 Gang Chen , Istvan Szapudi

Markov Chain Monte Carlo (MCMC) sampler is widely used for cosmological parameter estimation from CMB and other data. However, due to the intrinsic serial nature of the MCMC sampler, convergence is often very slow. Here we present a fast…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-12 Santanu Das , Tarun Souradeep

Accurate modelling of redshift-space distortions (RSD) is challenging in the non-linear regime for two-point statistics e.g. the two-point correlation function (2PCF). We take a different perspective to split the galaxy density field…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-14 Enrique Paillas , Yan-Chuan Cai , Nelson Padilla , Ariel Sánchez

Measuring the two-point correlation function of the galaxies in the Universe gives access to the underlying dark matter distribution, which is related to cosmological parameters and to the physics of the primordial Universe. The estimation…

A polarimetric synthetic aperture radar (PolSAR) system, which uses multiple images acquired with different polarizations in both transmission and reception, has the potential to improve the description and interpretation of the observed…

Signal Processing · Electrical Eng. & Systems 2025-07-08 Dehbia Hanis , Luca Pallotta , Augusto Aubry , Aichouche Belhadj-Aissa , Antonio De Maio

We analyze the recent Multi-index Stochastic Collocation (MISC) method for computing statistics of the solution of a partial differential equation (PDEs) with random data, where the random coefficient is parametrized by means of a countable…

Numerical Analysis · Mathematics 2016-07-22 Abdul-Lateef Haji-Ali , Fabio Nobile , Lorenzo Tamellini , Raul Tempone

The measurement of Doppler velocity shifts in spectra is a ubiquitous theme in astronomy, usually handled by computing the cross-correlation of the signals, and finding the location of its maximum. This paper addresses the problem of the…

Astrophysics · Physics 2008-11-26 Carlos Allende Prieto

We constrain the spectral index of polarized synchrotron emission, $\beta_s$, by correlating the recently released 2.3 GHz S-Band Polarization All Sky Survey (S-PASS) data with the 23 GHz 9-year Wilkinson Microwave Anisotropy Probe (WMAP)…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-12 U. Fuskeland , K. J. Andersen , R. Aurlien , R. Banerji , M. Brilenkov , H. K. Eriksen , M. Galloway , E. Gjerløw , S. K. Næss , T. L. Svalheim , I. K. Wehus

We present a simulation-based cosmological analysis using a combination of Gaussian and non-Gaussian statistics of the weak lensing mass (convergence) maps from the first three years (Y3) of the Dark Energy Survey (DES). We implement: 1)…

The interpretation of cosmological observables requires the use of increasingly sophisticated theoretical models. Since these models are becoming computationally very expensive and display non-trivial uncertainties, the use of standard…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Marcos Pellejero-Ibañez , Raul E. Angulo , Giovanni Aricó , Matteo Zennaro , Sergio Contreras , Jens Stücker

In this letter, we propose a novel technique for obtaining scattering components from Polarimetric Synthetic Aperture Radar (PolSAR) data using the geodesic distance on the unit sphere. This geodesic distance is obtained between an…

Computer Vision and Pattern Recognition · Computer Science 2025-05-27 Debanshu Ratha , Avik Bhattacharya , Alejandro C. Frery

In the past few years, several independent collaborations have presented cosmological constraints from tomographic cosmic shear analyses. These analyses differ in many aspects: the datasets, the shear and photometric redshift estimation…

Focusing on the well motivated aperture mass statistics $\Map$, we study the possibility of constraining cosmological parameters using future space based SNAP class weak lensing missions. Using completely analytical results we construct the…

Astrophysics · Physics 2007-05-23 Dipak Munshi , Patrick Valageas

Convergence maps of the integrated matter distribution are a key science result from weak gravitational lensing surveys. To date, recovering convergence maps has been performed using a planar approximation of the celestial sphere. However,…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-16 Christopher G. R. Wallis , Matthew A. Price , Jason D. McEwen , Thomas D. Kitching , Boris Leistedt , Antoine Plouviez

Although extensive research exists in spatial modeling, few studies have addressed finite mixture model-based clustering methods for spatial data. Finite mixture models, especially Gaussian mixture models, particularly suffer from high…

A number of well-motivated extensions of the LCDM concordance cosmological model postulate the existence of a population of sources embedded in the cosmic microwave background (CMB). One such example is the signature of cosmic bubble…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-29 J. D. McEwen , S. M. Feeney , M. C. Johnson , H. V. Peiris