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The diffuse gamma ray emission from astrophysical backgrounds in our Galaxy and the signal due to the annihilation or decay of Dark Matter (DM) in the Galactic Halo are expected to have a substantially different morphology and spectral…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Gabrijela Zaharijas , Alessandro Cuoco , Zhaoyu Yang , Jan Conrad

The Sun emits copious amounts of photons and neutrinos in an approximately spatially isotropic distribution. Diffuse $\gamma$-rays and ultra-high energy (UHE) neutrinos from extragalactic sources may subsequently interact and annihilate…

High Energy Astrophysical Phenomena · Physics 2024-07-22 Shyam Balaji

Previously we proposed a novel method to inspect the isotropy of the properties of gamma-ray bursts (GRBs) such as their duration, fluences and peak fluxes at various energy bands and different time scales, complementary to existing studies…

High Energy Astrophysical Phenomena · Physics 2019-05-07 Jakub Řípa , Arman Shafieloo

A novel application of machine-learning (ML) based image processing algorithms is proposed to analyze an all-sky map (ASM) obtained using the Fermi Gamma-ray Space Telescope. An attempt was made to simulate a one-year ASM from a…

High Energy Astrophysical Phenomena · Physics 2021-06-02 Shogo Sato , Jun Kataoka , Soichiro Ito , Jun'ichi Kotoku , Masato Taki , Asuka Oyama , Takaya Toyoda , Yuki Nakamura , Marino Yamamoto

A new method for modelling spherically symmetric inhomogeneities is applied to the formation of clusters in an expanding Universe. We impose simple initial velocity and density perturbations of finite extent and we investigate the…

Astrophysics · Physics 2009-10-31 Y. Dabrowski , M. P. Hobson , A. N. Lasenby , C. J. L. Doran

We analyze fermionic response of strongly correlated holographic matter in presence of inhomogeneous periodically modulated potential mimicking the crystal lattice. The modulation is sourced by a scalar operator that explicitly breaks the…

High Energy Physics - Theory · Physics 2020-01-29 Askar Iliasov , Andrey A. Bagrov , Mikhail I. Katsnelson , Alexander Krikun

We consider the anisotropy properties of a background radiation in the fractal cosmological model. The space of this model includes self-similar domains. The metric tensors of any two domains are connected by the discrete scaling…

General Physics · Physics 2012-07-20 I. K. Rozgacheva , A. A. Agapov

We consider a perfectly homogeneous, isotropic and spatially flat universe which undergoes a sudden phase transition producing topological defects. We assume that these defects form a coherent network which scales like the background…

Astrophysics · Physics 2007-05-23 Jean-Philippe Uzan , Nathalie Deruelle , Alain Riazuelo

A coherent definition of the reflection and transmission factors at a plane interface separating two uniaxial crystals is proposed, from the photons impulsion-energy 4-vectors conservation. This definition, different from the classical…

Optics · Physics 2010-04-05 Vital LeDez , Hamou Sadat

Fitting spectral distributions of total fluxes or image intensities are two standard methods for estimating the masses of starless cores and protostellar envelopes. These mass estimates, which are the main source and basis of our knowledge…

Instrumentation and Methods for Astrophysics · Physics 2016-09-28 Alexander Men'shchikov

Modifications on the predictions about the matter power spectrum based on the hypothesis of a tiny contribution from a degenerate Fermi gas (DFG) test-fluid to some dominant cosmological scenario are investigated. Reporting about the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 E. L. D. Perico , Alex E. Bernardini

All-sky explorations by Fermi-LAT have revolutionized our view of the gamma-ray sky. While its ongoing all-sky survey counts thousands of sources, essential issues related to the nature of unassociated sources call for sensitive all-sky…

High Energy Astrophysical Phenomena · Physics 2016-06-22 Eugenio Bottacini , Marco Ajello

Raman spectroscopy has attracted interest as a non-invasive optical technique to study the composition and structure of a wide range of materials at the microscopic level. The intrinsic fluorescence background can be orders of magnitude…

Materials Science · Physics 2015-10-28 P. J. Cadusch , M. M. Hlaing , S. A. Wade , S. L. McArthur , P. R. Stoddart

The Density Based Spatial Clustering of Applications with Noise (DBSCAN) is a topometric algorithm used to cluster spatial data that are affected by background noise. For the first time, we propose the use of this method for the detection…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 A. Tramacere , C. Vecchio

We calculate intensity and angular power spectrum of the cosmological background of synchrotron emission from cold dark matter annihilations into electron positron pairs. We compare this background with intensity and anisotropy of…

Astrophysics · Physics 2011-07-13 Le Zhang , Guenter Sigl

Under the assumption that the concordance Lambda cold dark matter (CDM) model is the correct model, we test the cosmic microwave background (CMB) anisotropy data for systematic effects by examining the band pass temperature residuals with…

Astrophysics · Physics 2007-05-23 Louise M. Griffiths , Charles H. Lineweaver

We propose an unsupervised real-time dense depth completion from a sparse depth map guided by a single image. Our method generates a smooth depth map while preserving discontinuity between different objects. Our key idea is a Binary…

Computer Vision and Pattern Recognition · Computer Science 2020-07-17 Yasuhiro Yao , Menandro Roxas , Ryoichi Ishikawa , Shingo Ando , Jun Shimamura , Takeshi Oishi

Recently a symmetry-based method to test for statistical isotropy of the cosmic microwave background was developed. We apply the method to template-cleaned 3-year and 5-year WMAP-$DA$ maps. We examine a wide range of angular multipoles from…

Astrophysics · Physics 2010-11-02 Pramoda Kumar Samal , Rajib Saha , Pankaj Jain , John P. Ralston

A probabilistic two-component mixture model allows one to separate the diffuse background from the celestial sources within a one-step algorithm without data censoring. The background is modeled with a thin-plate spline combined with the…

Instrumentation and Methods for Astrophysics · Physics 2012-02-03 F. Guglielmetti , H. Boehringer , R. Fischer , P. Rosati , P. Tozzi

The theoretical basis for the prediction of anisotropies in the cosmic microwave background is very well developed. Very low amplitude density and temperature perturbations produce small gravitational effects, leading to an anisotropy that…

Astrophysics · Physics 2007-05-23 E. L. Wright