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We analyze the $^{115}$In $\beta$-decay energy spectrum through the spectral moment method (SMM), previously introduced in the context of $^{113}$Cd $\beta$ decay. The spectral moments $\mu_n$ are defined as averaged $n^{\rm th}$ powers of…

Nuclear Theory · Physics 2024-05-21 Joel Kostensalo , Eligio Lisi , Antonio Marrone , Jouni Suhonen

Modern reconstruction methods for magnetic resonance imaging (MRI) exploit the spatially varying sensitivity profiles of receive-coil arrays as additional source of information. This allows to reduce the number of time-consuming…

Medical Physics · Physics 2017-09-12 Martin Uecker

The division of Gamma-ray bursts (GRBs) into different classes, other than the "short" and "long", has been an active field of research. We investigate whether GRBs can be classified based on a broader set of parameters, including prompt…

High Energy Astrophysical Phenomena · Physics 2023-11-28 Shubham Bhardwaj , Maria G. Dainotti , Sachin Venkatesh , Aditya Narendra , Anish Kalsi , Enrico Rinaldi , Agnieszka Pollo

Gamma-ray bursts (GRBs) are commonly attributed to the demise of massive stars or the merger of binary compact objects. However, their varied emission characteristics strongly imply the existence of multiple GRB classes based on progenitor…

High Energy Astrophysical Phenomena · Physics 2024-07-12 Nishil Mehta , Shabnam Iyyani

We exploit the 14 gamma-ray bursts (GRBs) with known redshifts z and the 7 GRBs for which there are constraints on z to determine the GRB rate R_{GRB}(z), using a method based on Bayesian inference. We find that, despite the qualitative…

Astrophysics · Physics 2009-11-07 Nevin Weinberg , Carlo Graziani , Donald Q. Lamb , Daniel E. Reichart

We consider the problem of how to compute eigenvalues of a self-adjoint operator when a direct application of the Galerkin (finite-section) method is unreliable. The last two decades have seen the development of the so-called quadratic…

Spectral Theory · Mathematics 2015-06-16 James Hinchcliffe , Michael Strauss

Using the modified internal shock wave model we fit the gamma ray burst (GRB) light and spectral curves of 30 GRBs observed with BATSE. From the best fitting we obtain basic parameters of the relativistic shells which are in good agreement…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Sasa Simić , Luka Č. Popović

The inverse eigenvalue problem of a graph $G$ is the problem of characterizing all lists of eigenvalues of real symmetric matrices whose off-diagonal pattern is prescribed by the adjacencies of $G$. The strong spectral property is a…

Combinatorics · Mathematics 2023-06-07 Jephian C. -H. Lin , Polona Oblak , Helena Šmigoc

The spectral shape of the unresolved emission from different classes of gamma-ray emitters can be used to disentangle the contributions from these populations to the extragalactic gamma-ray background (EGRB). We present a calculation of the…

Astrophysics · Physics 2010-11-11 Vasiliki Pavlidou , Tonia M. Venters

The Diffusion Entropy algorithm is a method that allows the study of correlated non stationary time series and allows the discrimination between signal and uncorrelated noise. DE provides a quantitative measure of the complexity by means of…

Astrophysics · Physics 2009-11-10 N. Omodei , J. Bellazzini , S. Montangero

Blind source separation is one of the major analysis tool to extract relevant information from multichannel data. While being central, joint deconvolution and blind source separation (DBSS) methods are scarce. To that purpose, a DBSS…

Signal Processing · Electrical Eng. & Systems 2020-09-09 R. Carloni Gertosio , J. Bobin

In this work, an efficient numerical scheme is presented for seismic blind deconvolution in a multichannel scenario. The proposed method iterate with wo steps: first, wavelet estimation across all channels and second, refinement of the…

Computational Physics · Physics 2020-10-20 Naveed Iqbal , Entao Liu , James H. McClellan , Abdullatif A. Al-Shuhail

In traditional QCD sum rules, the simple hadron spectral density model of ``delta-function-type ground state + theta-function-type continuous spectrum" determines that there is no perfect parameter selection. In recent years, inverse…

High Energy Physics - Phenomenology · Physics 2024-07-16 Zhen-Xing Zhao , Yi-Peng Xing , Run-Hui Li

A quantum mechanical method of calculation of bremsstrahlung spectra in alpha-decay of heavy nuclei with taking into account an angle between directions of the alpha-particle motion and the photon emission is presented. Dependence between…

Nuclear Theory · Physics 2008-07-24 Sergei P. Maydanyuk , Sergei V. Belchikov

The Large Area Telescope (LAT) onboard the Fermi satellite is observing the gamma-ray sky in the high energy region, above 20 MeV. We have developed a method to reconstruct the energy spectra of the gamma-rays detected by the Fermi LAT…

Instrumentation and Methods for Astrophysics · Physics 2019-08-13 F. Loparco , M. N. Mazziotta

X-ray interaction with matter is an energy-dependent process that is contingent on the atomic structure of the constituent material elements. The most advanced models to capture this relationship currently rely on Monte Carlo (MC)…

Machine Learning · Computer Science 2023-07-11 Raziye Kubra Kumrular , Thomas Blumensath

A multivariate analysis of gamma-ray burst (GRB) bulk properties is presented to discriminate between distinct classes of GRBs. Several variables representing burst duration, fluence and spectral hardness are considered. Two multivariate…

Light interreflections occurring in a concave object generate a color gradient which is characteristic of the object's spectral reflectance. In this paper, we use this property in order to estimate the spectral reflectance of matte,…

Computer Vision and Pattern Recognition · Computer Science 2018-07-04 Rada Deeb , Damien Muselet , Mathieu Hebert , Alain Tremeau

The emission processes active in the highly relativistic jets of gamma-ray bursts (GRBs) remain unknown. In this paper we propose a new measure to describe spectra: the width of the $EF_E$ spectrum, a quantity dependent only on finding a…

High Energy Astrophysical Phenomena · Physics 2015-01-20 Magnus Axelsson , Luis Borgonovo

Gamma-ray bursts represent some of the most energetic and complex phenomena in the universe, characterized by highly variable light curves that often contain observational gaps. Reconstructing these light curves is essential for gaining…

High Energy Astrophysical Phenomena · Physics 2026-01-30 Zhunuskanov A. , Sakan A. , Akhmetali A. , Zaidyn M. , Ussipov N