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The annihilation of dark matter particles in the halo of galaxies may end up into gamma rays, which travel almost unperturbed till to their detection at Earth. This annihilation signal can exhibit an anisotropic behavior quantified by the…

High Energy Astrophysical Phenomena · Physics 2014-06-19 F. Calore , V. De Romeri , M. Di Mauro , F. Donato , J. Herpich , A. V. Maccio' , L. Maccione

The useful dynamic range of an image in the diffraction limited regime is usually limited by speckles caused by residual phase errors in the optical system forming the image. The technique of speckle decorrelation involves introducing many…

Astrophysics · Physics 2007-05-23 Anand Sivaramakrishnan , James P. Lloyd , Philip E. Hodge , Bruce A. Macintosh

When a plane electromagnetic wave impinges upon a diffraction grating or other periodic structures, reflected and transmitted waves propagate away from the structure in different radiation channels. A diffraction anomaly occurs when the…

Computational Physics · Physics 2022-10-05 Zitao Mai , Ya Yan Lu

A spatially varying blur kernel $h(\mathbf{x},\mathbf{u})$ is specified by an input coordinate $\mathbf{u} \in \mathbb{R}^2$ and an output coordinate $\mathbf{x} \in \mathbb{R}^2$. For computational efficiency, we sometimes write…

Signal Processing · Electrical Eng. & Systems 2024-03-12 Nicholas Chimitt , Xingguang Zhang , Yiheng Chi , Stanley H. Chan

The spectra of black hole binaries in the low/hard state are complex, with evidence for multiple different Comptonisation regions contributing to the hard X-rays in addition to a cool disc component. We show this explicitly for some of the…

High Energy Astrophysical Phenomena · Physics 2018-07-25 M. Axelsson , C. Done

Scattering of electromagnetic waves lies at the heart of most experimental techniques over nearly the entire electromagnetic spectrum, ranging from radio waves to optics and X-rays. Hence, deep insight into the basics of scattering theory…

A review on the spectral and temporal properties of gamma-ray bursts is given. Special attention is paid to the spectral evolution of their continuum emission and its connection to the time evolution of the intensity. Efforts on…

Astrophysics · Physics 2009-09-25 Felix Ryde

Spectrum sensing is of critical importance in any cognitive radio system. When the primary user's signal has uncertain parameters, the likelihood ratio test, which is the theoretically optimal detector, generally has no closed-form…

Signal Processing · Electrical Eng. & Systems 2019-08-07 Ziyu Ye , Qihang Peng , Kelly Levick , Hui Rong , Andrew Gilman , Pamela Cosman , Larry Milstein

Gaussian processes are rich distributions over functions, which provide a Bayesian nonparametric approach to smoothing and interpolation. We introduce simple closed form kernels that can be used with Gaussian processes to discover patterns…

Machine Learning · Statistics 2014-01-03 Andrew Gordon Wilson , Ryan Prescott Adams

Velocity map imaging spectroscopy is a powerful technique for detecting the momentum distribution of photoelectrons resulting from an ionization experiment on atoms or molecules. However, when used with ultraviolet light sources, scattered…

The paper presents real time speckle de-noising based on activity computation algorithm and wavelet transform. Speckles arise in an image when laser light is reflected from an illuminated surface. The process involves detection of speckles…

Computer Vision and Pattern Recognition · Computer Science 2014-05-27 D. Sachin Kumar , P. R. Seshadri , N. Vaishnav , Dr. Saraswathi Janaki

It is believed that the observed diffuse gamma ray emission from the galactic plane is the result of interactions between cosmic rays and the interstellar gas. Such emission can be amplified if cosmic rays penetrate into dense molecular…

Astrophysics · Physics 2008-11-26 Stefano Gabici , Felix Aharonian , Pasquale Blasi

Experimental data in particle and nuclear physics, particle astrophysics, and radiation protection dosimetry are collected using experimental facilities that consist of a complex system of sensors, electronics, and software. Measured…

Data Analysis, Statistics and Probability · Physics 2026-03-04 Nikolay D. Gagunashvili

The acceleration times of the highest-energy particles which emit gamma-rays in young and middle-age SNRs are comparable with SNR age. If the number of particles starting acceleration was varying during early times after the supernova…

High Energy Astrophysical Phenomena · Physics 2017-09-20 O. Petruk , S. Orlando , M. Miceli , F. Bocchino

Scattering obscures information carried by wave by producing a speckle pattern, posing a common challenge across various fields, including microscopy and astronomy. Traditional methods for extracting information from speckles often rely on…

The recent implementation of radiative transfer algorithms in numerous hydrodynamics codes has led to a dramatic improvement in studies of feedback in various astrophysical environments. However, because of methodological limitations and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jordan Mirocha , Stephen Skory , Jack O. Burns , John H. Wise

A new and simple technique has been developed using plastic scintillator detectors for gamma ray and cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In these experiments only a leading edge…

Instrumentation and Detectors · Physics 2015-04-13 Akhilesh P. Nandan , Sharmili Rudra , Himangshu Neog , S. Biswas , S. Mahapatra , B. Mohanty , P. K. Samal

The most important systematical errors in determination of level density and radiative strength functions for deformed nuclei have been estimated from the gamma-ray spectra in nuclear reactions like the stripping or pickup reactions.

In recent years, there has been a proliferation of wide-field sky surveys to search for a variety of transient objects. Using relatively short focal lengths, the optics of these systems produce undersampled stellar images often marred by a…

Astrophysics · Physics 2009-11-13 Fang Yuan , Carl W. Akerlof

Hyperspectral unmixing is an important remote sensing task with applications including material identification and analysis. Characteristic spectral features make many pure materials identifiable from their visible-to-infrared spectra, but…

Computer Vision and Pattern Recognition · Computer Science 2020-07-14 John Janiczek , Parth Thaker , Gautam Dasarathy , Christopher S. Edwards , Philip Christensen , Suren Jayasuriya