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In many situations, sample data is obtained from a noisy or imperfect source. In order to address such corruptions, this paper introduces the concept of a sampling corrector. Such algorithms use structure that the distribution is purported…

Data Structures and Algorithms · Computer Science 2018-04-03 Clément Canonne , Themis Gouleakis , Ronitt Rubinfeld

We investigate the prospects for using the weak lensing bispectrum alongside the power spectrum to control systematic uncertainties in a Euclid-like survey. Three systematic effects are considered: the intrinsic alignment of galaxies,…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-02 Susan Pyne , Benjamin Joachimi

Reliable extraction of cosmological information from clustering measurements of galaxy surveys requires estimation of the error covariance matrices of observables. The accuracy of covariance matrices is limited by our ability to generate…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-29 Mohammadjavad Vakili , Francisco-Shu Kitaura , Yu Feng , Gustavo Yepes , Cheng Zhao , Chia-Hsun Chuang , ChangHoon Hahn

While substantial progress has been made in studying the pre-reconstruction galaxy bispectrum, investigations of the post-reconstruction bispectrum are still in nascent stages. In this paper, we present a bispectrum model that incorporates…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-28 Naonori Sugiyama

[Abridged] Non-uniform sampling and gaps in sky coverage are common in galaxy redshift surveys, but these effects can degrade galaxy counts-in-cells and density estimates. We carry out a comparison of methods that aim to fill the gaps to…

A large fraction of the information collected by cosmological surveys is simply discarded to avoid lengthscales which are difficult to model theoretically. We introduce a new technique which enables the extraction of useful information from…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-08 Fergus Simpson , J. Berian James , Alan F. Heavens , Catherine Heymans

Redshifts used in current cosmological supernova samples are measured using two primary techniques, one based on well-measured host galaxy spectral lines and the other based on supernova-dominated spectra. Here, we construct an updated…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-20 Charles L. Steinhardt , Albert Sneppen , Bidisha Sen

Line intensity mapping (LIM) is a rapidly emerging technique for constraining cosmology and galaxy formation using multi-frequency, low angular resolution maps. Many LIM applications crucially rely on cross-correlations of two line…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-29 Emmanuel Schaan , Martin White

The cross-correlation between 21-cm intensity mapping experiments and photometric surveys of galaxies (or any other cosmological tracer with a broad radial kernel) is severely degraded by the loss of long-wavelength radial modes due to…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-19 Caroline Guandalin , Isabella P. Carucci , David Alonso , Kavilan Moodley

We present a Neural Network based emulator for the galaxy redshift-space power spectrum that enables several orders of magnitude acceleration in the galaxy clustering parameter inference, while preserving 3$\sigma$ accuracy better than…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-03 Svyatoslav Trusov , Pauline Zarrouk , Shaun Cole

The first direct measurements of the HI intensity mapping power spectrum were recently made using the MeerKAT telescope. These measurements are on nonlinear scales, at redshifts 0.32 and 0.44. We develop a formalism for modelling…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-17 Hamsa Padmanabhan , Roy Maartens , Obinna Umeh , Stefano Camera

We present the DARTH FADER algorithm, a new wavelet-based method for estimating redshifts of galaxy spectra in spectral surveys that is particularly adept in the very low SNR regime. We use a standard cross-correlation method to estimate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 D. P. Machado , A. Leonard , J. -L. Starck , F. B. Abdalla , S. Jouvel

A new and promising avenue was recently developed for analyzing large-scale structure data with a model-independent approach, in which the linear power spectrum shape is parametrized with a large number of freely varying wavebands rather…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-24 Luca Amendola , Marco Marinucci , Massimo Pietroni , Miguel Quartin

We describe a simple but efficient method for deriving a consistent set of monopole and dipole corrections for multi-frequency sky map data sets, allowing robust parametric component separation with the same data set. The computational core…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-01 I. K. Wehus , U. Fuskeland , H. K. Eriksen , A. J. Banday , C. Dickinson , T Ghosh , K. M. Gorski , C. R. Lawrence , J. P. Leahy , D. Maino , P. Reich , W. Reich

We trained denoiser autoencoding neural networks on medium resolution simulated optical spectra of late-type stars to demonstrate that the reconstruction of the original flux is possible at a typical relative error of a fraction of a…

Instrumentation and Methods for Astrophysics · Physics 2024-09-19 Balázs Pál , László Dobos

Visbal & Loeb (2010) have shown that it is possible to measure the clustering of galaxies by cross correlating the cumulative emission from two different spectral lines which originate at the same redshift. Through this cross correlation,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Eli Visbal , Hy Trac , Abraham Loeb

We present a new method to estimate redshift distributions and galaxy-dark matter bias parameters using correlation functions in a fully data driven and self-consistent manner. Unlike other machine learning, template, or correlation…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-09 Ben Hoyle , Markus Michael Rau

Using an example of the Abell 2634 galaxy cluster we discuss the effect of contamination of kinematic data by interlopers and its impact on mass modelling. The cluster data reveal rich substructure along the line of sight. We demonstrate…

Astrophysics · Physics 2007-12-18 Radoslaw Wojtak , Ewa L. Lokas

We compare the model power spectrum, computed based on perturbation theory (PT) with the power spectrum of luminous red galaxies (LRG) measured from the SDSSDR7 catalog, assuming a flat, CDM-dominated cosmology. The model includes the…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-21 Shun Saito , Masahiro Takada , Atsushi Taruya

The marked power spectrum - a two-point correlation function of a transformed density field - has emerged as a promising tool for extracting cosmological information from the large-scale structure of the Universe. In this work, we present…

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