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We present here the analysis of X-rays point sources detected in several observations available in the XMM-Newton public archive. We focused, in particular, on energies below 1 keV, which are of particular relevance to the understanding of…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-13 Anjali Gupta , Massimiliano Galeazzi

We develop a novel method to separate the components of a diffuse emission process based on an association with the energy spectra. Most of the existing methods use some information about the spatial distribution of components, e.g.,…

Instrumentation and Methods for Astrophysics · Physics 2012-02-07 Dmitry Malyshev

We study the cross-correlation between maps of the unresolved $\gamma$-ray background constructed from the 12-year data release of the Fermi Large-Area Telescope, and the overdensity of galaxies in the redshift range $z\lesssim0.4$ as…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-29 Anya Paopiamsap , David Alonso , Deaglan J. Bartlett , Maciej Bilicki

It has been argued that the power spectrum of the anisotropies in the Cosmic Microwave Background (CMB) may be effectively degenerate, namely that the observable spectrum does not determine a unique set of cosmological parameters. We…

Astrophysics · Physics 2015-06-24 R. Benton Metcalf , Joseph Silk

About one third of Fermi Large Area Telescope (LAT) sources are unassociated. We perform multi-class classification of Fermi-LAT sources using machine learning with the goal of probabilistic classification of the unassociated sources. A…

High Energy Astrophysical Phenomena · Physics 2025-03-07 Dmitry V. Malyshev

We present a rigorous description of the general problem of aperture photometry in high energy astrophysics photon-count images, in which the statistical noise model is Poisson, not Gaussian. We compute the full posterior probability…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 F. A. Primini , V. L. Kashyap

We study the Fermi liquid properties of the cold atomic dipolar Fermi gases with the explicit dipolar anisotropy using perturbative approaches. Due to the explicit dipolar anisotropy, Fermi surfaces exhibit distortions of the…

Quantum Gases · Physics 2010-02-22 Ching-Kit Chan , Congjun Wu , Wei-cheng Lee , S. Das Sarma

We study the relation between the measured anisotropies in the extragalactic diffuse gamma-ray background (DGRB) and the DGRB spectral intensity, and their potential origin from the unresolved blazar population. Using a physical-evolution…

High Energy Astrophysical Phenomena · Physics 2015-06-05 J. Patrick Harding , Kevork N. Abazajian

The motion of an observer in the rest frame of the cosmic 21-cm background induces an anisotropy in the observed background, even when the background is isotropic. The induced anisotropy includes a dipole and a quadrupole, in the order…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-19 Selim C. Hotinli , Kyungjin Ahn

We examine the constraints on the luminosity-dependent density evolution model for the evolution of blazars given the observed spectrum of the diffuse gamma-ray background (DGRB), blazar source-count distribution, and the blazar spectral…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Kevork N. Abazajian , Steve Blanchet , J. Patrick Harding

We propose an energy-stable parametric finite element method (ES-PFEM) to discretize the motion of a closed curve under surface diffusion with an anisotropic surface energy $\gamma(\theta)$ -- anisotropic surface diffusion -- in two…

Numerical Analysis · Mathematics 2021-10-26 Yifei Li , Weizhu Bao

Coherency misfit stresses and their related anisotropies are known to influence the equilibrium shapes of precipitates. Additionally, mechanical properties of the alloys are also dependent on the shapes of the precipitates. Therefore, in…

Materials Science · Physics 2018-08-29 Bhalchandra Bhadak , R. Sankarasubramanian , Abhik Choudhury

Over the past 16 years, the Fermi Large Area Telescope (LAT) has significantly advanced our view of the GeV gamma-ray sky, yet several key questions remain - such as the composition of the isotropic gamma-ray background, the origin of the…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Christopher Eckner , Noemi Anau Montel , Florian List , Francesca Calore , Christoph Weniger

Using the Cosmic Background Imager, a 13-element interferometer array operating in the 26-36 GHz frequency band, we have observed 40 sq deg of sky in three pairs of fields, each ~ 145 x 165 arcmin, using overlapping pointings (mosaicing).…

The Large Area Telescope (LAT) on board the \emph{Fermi} Gamma-ray Space Telescope has been continuously providing good quality survey data of the entire sky in the high energy range from 30 MeV to 500 GeV and above since August 2008. A…

High Energy Astrophysical Phenomena · Physics 2025-10-13 A. Pathania , K. K. Singh , S. K. Singh , A. Tolamatti , B. B. Singh , K. K. Yadav

We propose a new formalism to handle asymmetric beams in the data analysis of cosmic microwave background anisotropy experiments. For any beam shape, the formalism finds the optimal circularly symmetric equivalent and is thus easily…

In this paper, we estimate the cross-correlation power spectra between the Planck 2018 cosmic microwave background (CMB) temperature anisotropy map and the unresolved $\gamma$-ray background (UGRB) from the 9-years Fermi-Large Area…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-11 Xiu-Hui Tan , Ji-Ping Dai , Jun-Qing Xia

Can uncorrelated surrounding sound sources be used to generate extended diffuse sound fields? By definition, targets are a constant sound pressure level, a vanishing average sound intensity, uncorrelated sound waves arriving isotropically…

Audio and Speech Processing · Electrical Eng. & Systems 2024-02-22 Franz Zotter , Stefan Riedel , Lukas Gölles , Matthias Frank

A maximum-likelihood method is presented for estimating the power spectrum of anisotropies in the cosmic microwave background (CMB) from interferometer observations. The method calculates flat band-power estimates in separate bins in…

Astrophysics · Physics 2009-11-07 M. P. Hobson , Klaus Maisinger

The coherent image distortions induced by weak gravitational lensing can be used to measure the power spectrum of density inhomogeneities in the universe. We present our on-going effort to detect this effect with the FIRST radio survey,…

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