English
Related papers

Related papers: Tomography of the Galactic free electron density w…

200 papers

SKA is a new technology radio-telescope array, about two orders of magnitude more sensitive and rapid in sky surveys than present instruments. It will probe the dark age of the universe, just afer recombination, and during the epoch of…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Francoise Combes

We present the largest Wiener reconstruction of the cosmic density field made to date. The reconstruction is based on the Sloan Digital Sky Survey data release 6 covering the northern Galactic cap. We use a novel supersampling algorithm to…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-28 Francisco S. Kitaura , Jens Jasche , Cheng Li , Torsten A. Ensslin , R. Benton Metcalf , Benjamin D. Wandelt , Gerard Lemson , Simon D. M. White

We present a new Monte Carlo algorithm that produces results of high accuracy with reduced simulational effort. Independent random walks are performed (concurrently or serially) in different, restricted ranges of energy, and the resultant…

Statistical Mechanics · Physics 2009-10-31 Fugao Wang , D. P. Landau

Data analysis in high-dimensional spaces aims at obtaining a synthetic description of a data set, revealing its main structure and its salient features. We here introduce an approach providing this description in the form of a topography of…

Machine Learning · Statistics 2021-03-02 Maria d'Errico , Elena Facco , Alessandro Laio , Alex Rodriguez

We lay the foundations for a new fast method to reconstruct the electron density in x-ray scanning applications using measurements in the dark field. This approach is applied to a type of machine configuration with fixed energy sensitive…

Numerical Analysis · Mathematics 2015-05-08 James Webber

The non-Euclidean geometry of spacetime induces an anisotropy in the apparent correlation function of high-redshift quasars. This effect can constrain the cosmological constant \Lambda independent of any assumptions about evolution of…

Astrophysics · Physics 2009-10-30 Piotr A. Popowski , David H. Weinberg , Barbara S. Ryden , Patrick S. Osmer

Density level sets can be estimated using plug-in methods, excess mass algorithms or a hybrid of the two previous methodologies. The plug-in algorithms are based on replacing the unknown density by some nonparametric estimator, usually the…

Statistics Theory · Mathematics 2016-11-26 A. Rodríguez-Casal , P. Saavedra-Nieves

Most of the baryons in the Universe are thought to be contained within filaments of galaxies, but as yet, no single study has published the observed properties of a large sample of known filaments to determine typical physical…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Amelia Fraser-McKelvie , Kevin A. Pimbblet , Jasmina S. Lazendic

Photometric surveys have provided incredible amounts of astronomical information in the form of images. However, astronomical images often contain artifacts that can critically hinder scientific analysis by misrepresenting intensities or…

Instrumentation and Methods for Astrophysics · Physics 2020-06-03 Suchetha Cooray , Tsutomu T. Takeuchi , Moe Yoda , Kazuo Sorai

The overwhelming foreground causes severe contamination on the detection of 21-cm signal during the Epoch of Reionization (EoR). Among various foreground components, the Galactic free-free emission is less studied, so that its impact on the…

Astrophysics of Galaxies · Physics 2020-07-07 Xiaoli Lian , Haiguang Xu , Dongchao Zheng , Zhenghao Zhu , Dan Hu

We develop a novel statistical strong lensing approach to probe the cosmological parameters by exploiting multiple redshift image systems behind galaxies or galaxy clusters. The method relies on free-form mass inversion of strong lenses and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 M. Lubini , M. Sereno , J. Coles , Ph. Jetzer , P. Saha

In the next decade, radio telescopes like the Square Kilometer Array (SKA) will explore the Universe at high redshift, and particularly during the Epoch of Reionisation (EoR). The first structures emerged during this epoch, and their…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Emilie Thélie , Dominique Aubert , Nicolas Gillet , Julien Hiegel , Pierre Ocvirk

We present the results of a 6.1 square degree survey for clusters of galaxies via their Sunyaev- Zel'dovich (SZ) effect at 31 GHz. From late 2005 to mid 2007 the Sunyaev-Zel'dovich Array (SZA) observed four fields of roughly 1.5 square…

(abridged) We perform a reconstruction of the cosmological large scale flows in the nearby Universe using two complementary observational sets. The first, the SFI++ sample of Tully-Fisher (TF) measurements of galaxies, provides a direct…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Marc Davis , Adi Nusser , Karen Masters , Christopher Springob , John P. Huchra , Gerard Lemson

Measuring the density profile of dark matter in the Solar neighborhood has important implications for both dark matter theory and experiment. In this work, we apply autoregressive flows to stars from a realistic simulation of a Milky…

Astrophysics of Galaxies · Physics 2023-03-29 Matthew R Buckley , Sung Hak Lim , Eric Putney , David Shih

We allow for nonlinear effects in the likelihood analysis of galaxy peculiar velocities, and obtain ~35%-lower values for the cosmological density parameter Om and the amplitude of mass-density fluctuations. The power spectrum in the linear…

Astrophysics · Physics 2009-11-06 L. Silberman , A. Dekel , A. Eldar , I. Zehavi

The COSMOS field has been the subject of a wide range of observations, with a number of studies focusing on reconstructing the 3D dark matter density field. Typically, these studies have focused on one given method or tracer. In this paper,…

The Square Kilometre Array (SKA) will operate in frequency ranges often used by military radar and other communications technology. It has been shown that if Extraterrestrial Intelligences (ETIs) communicate using similar technology, then…

Earth and Planetary Astrophysics · Physics 2015-05-19 D. H. Forgan , R. C. Nichol

We present a new non-parametric Jeans code, GravSphere, that recovers the density $\rho(r)$ and velocity anisotropy $\beta(r)$ of spherical stellar systems, assuming only that they are in a steady-state. Using a large suite of mock data, we…

Astrophysics of Galaxies · Physics 2017-09-06 J. I. Read , P. Steger

Binary (and trinary) radio pulsars are natural laboratories in space for understanding gravity in the strong field regime, with many unique and precise tests carried out so far, including the most precise tests of the strong equivalence…