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We propose a method to probe higher-order correlators of the primordial density field through the inhomogeneity of local non-Gaussian parameters, such as f_NL, measured within smaller patches of the sky. Correlators between n-point…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-28 Christian T. Byrnes , Sami Nurmi , Gianmassimo Tasinato , David Wands

The filtering of a Markov diffusion process on a manifold from counting process observations leads to `large' changes in the conditional distribution upon an observed event, corresponding to a multiplication of the density by the intensity…

Optimization and Control · Mathematics 2019-11-01 Simone Carlo Surace , Anna Kutschireiter , Jean-Pascal Pfister

Analyses of the galaxy N-Point Correlation Functions (NPCFs) have a large number of degrees of freedom, meaning one cannot directly estimate an invertible covariance matrix purely from mock catalogs, as has been the standard approach for…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Jessica Chellino , Alessandro Greco , Simon May , Zachary Slepian

Accurate astrometry and photometry of saturated and coronagraphic point spread functions (PSFs) are fundamental to both ground- and space-based high contrast imaging projects. For ground-based adaptive optics imaging, differential…

Astrophysics · Physics 2008-11-26 C. Marois , D. Lafreniere , B. Macintosh , R. Doyon

We derive analytic covariance matrices for the $N$-Point Correlation Functions (NPCFs) of galaxies in the Gaussian limit. Our results are given for arbitrary $N$ and projected onto the isotropic basis functions of Cahn & Slepian (2020),…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-31 Jiamin Hou , Robert N. Cahn , Oliver H. E. Philcox , Zachary Slepian

Employing Fermi-LAT gamma ray observations, several independent groups have found excess extended gamma ray emission at the Galactic center (GC). Both, annihilating dark matter (DM) or a population of $\sim 10^3$ unresolved millisecond…

High Energy Astrophysical Phenomena · Physics 2013-12-12 Chris Gordon , Oscar Macias

The total anisotropy of a diffuse background composed of two or more sources, such as the Fermi-LAT--measured gamma-ray background, is set by the anisotropy of each source population and the contribution of each population to the total…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-14 Brandon S. Hensley , Vasiliki Pavlidou , Jennifer M. Siegal-Gaskins

Gaussian cosmic microwave background skies are fully specified by the power spectrum. The conventional method of characterizing non-Gaussian skies is to evaluate higher order moments, the n-point functions and their Fourier transforms. We…

Astrophysics · Physics 2011-05-10 Pedro G. Ferreira , Joao Magueijo

The nature of the GeV gamma-ray Galactic center excess (GCE) in the data of Fermi-Large Area Telescope (LAT) is still to be unveiled. We present a new analysis of the inner Galaxy Fermi-LAT data at energies above 10 GeV, based on an…

High Energy Astrophysical Phenomena · Physics 2024-05-27 Silvia Manconi , Francesca Calore , Fiorenza Donato

Source apportionment analysis, which aims to quantify the attribution of observed concentrations of multiple air pollutants to specific sources, can be formulated as a non-negative matrix factorization (NMF) problem. However, NMF is…

Statistics Theory · Mathematics 2025-10-08 Bora Jin , Abhirup Datta

Despite the growing number of gamma-ray sources detected by Fermi-LAT, about one third of the sources in each survey remains of uncertain type. We present a new deep neural network approach for the classification of unidentified or…

High Energy Astrophysical Phenomena · Physics 2021-09-28 Thorben Finke , Michael Krämer , Silvia Manconi

This paper considers filters (the Mexican hat wavelet, the matched and the scale-adaptive filters) that optimize the detection/separation of point sources on a background. We make a one-dimensional treatment, we assume that the sources have…

Astrophysics · Physics 2009-11-07 R. B. Barreiro , J. L. Sanz , D. Herranz , E. Martinez-Gonzalez

The aim of this work is to improve models for the gamma-ray discrete or small-scale structure related to H2 interstellar gas. Reliably identifying this contribution is important to disentangle gamma-ray point sources from interstellar gas,…

High Energy Astrophysical Phenomena · Physics 2023-07-12 Christopher M. Karwin , Alex Broughton , Simona Murgia , Alexander Shmakov , Mohammadamin Tavakoli , Pierre Baldi

Nonlinear cosmological fields like galaxy density and lensing convergence can be approximately related to Gaussian fields via analytic point transforms. The lognormal transform (LN) has been widely used and is a simple example of a function…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-08 Kunhao Zhong , Gary Bernstein , Supranta S. Boruah , Bhuvnesh Jain , Sanjit Kobla

The small angular scale fluctuations of the (on large scale) isotropic gamma-ray background (IGRB) carry information about the presence of unresolved source classes. A guaranteed contribution to the IGRB is expected from the unresolved…

High Energy Astrophysical Phenomena · Physics 2019-08-15 A. Cuoco , T. Linden , M. N. Mazziotta , J. M. Siegal-Gaskins , Vincenzo Vitale , E. Komatsu

The Fermi-LAT collaboration has studied the gamma-ray emission from a stacked population of dwarf spheroidal galaxies and used this information to set constraints on the dark matter annihilation cross section. Interestingly, their analysis…

High Energy Astrophysical Phenomena · Physics 2015-03-11 Eric Carlson , Dan Hooper , Tim Linden

Searching for as yet undetected gamma-ray sources is a major target of the Fermi LAT Collaboration. We present an algorithm capable of identifying such type of sources by non-parametrically clustering the directions of arrival of the…

Instrumentation and Methods for Astrophysics · Physics 2023-01-30 Anna Montin , Alessandra R. Brazzale , Giovanna Menardi

We perform a detailed study of the sensitivity to the anisotropies related to Dark Matter (DM) annihilation in the Isotropic Gamma-Ray Background (IGRB) as measured by the Fermi Large Area Telescope (Fermi-LAT). For the first time, we take…

High Energy Astrophysical Phenomena · Physics 2011-09-07 A. Cuoco , A. Sellerholm , J. Conrad , S. Hannestad

We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand…

Astrophysics · Physics 2011-02-11 W. H. de Vries , S. S. Olivier , S. J. Asztalos , L. J. Rosenberg , K. L. Baker

The fluctuations produced during cosmic inflation may exhibit non-Gaussian characteristics that are imprinted in the large-scale structure of the Universe. This non-Gaussian imprint is an ultra-large scale signal that can be detected using…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-11 Mponeng Kopana , Sheean Jolicoeur , Roy Maartens