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Deconvolving COMPTEL gamma-ray data into images presents a major methodological challenge. We developed a new algorithm called Multiresolution Regularized Expectation Maximization (MREM), which explicitly accounts for spatial correlations…

In the context of dynamic emission tomography, the conventional processing pipeline consists of independent image reconstruction of single time frames, followed by the application of a suitable kinetic model to time activity curves (TACs)…

Applications · Statistics 2018-08-28 Michele Scipioni , Stefano Pedemonte , Maria Filomena Santarelli , Luigi Landini

Recovering physical properties of objects in motion is a core task across scientific and industrial applications. When the relative motion between the object and the sensing apparatus provides sufficient angular coverage, Computerized…

Numerical Analysis · Mathematics 2026-05-19 Daniel Burrows , Can Evren Yarman , Ozan Öktem

Recent observations of gamma-ray bursts (GRBs) have provided growing evidence for collimated outflows and emission, and strengthened the connection between GRBs and supernovae. If massive stars are the progenitors of GRBs, the hard photon…

Astrophysics · Physics 2009-10-31 Piero Madau , Roger D. Blandford , Martin J. Rees

A key diagnostic in warm-dense matter (WDM) experiments is X-ray Thomson scattering (XRTS), but its interpretation is often limited by complex instrument effects and the high computationally expensive combinations of microscopic models with…

We present a new algorithm, FRiM (FRactal Iterative Method), aiming at the reconstruction of the optical wavefront from measurements provided by a wavefront sensor. As our application is adaptive optics on extremely large telescopes, our…

Mathematical Physics · Physics 2015-05-18 Eric Thiebaut , Michel Tallon

Inter-crystal scattering (ICS) in Positron Emission Tomography (PET) is commonly regarded as a degradation effect that might compromise the image spatial resolution. In parallel, the inclusion of ICS events has also been recognized as a…

Medical Physics · Physics 2026-05-12 Jorge Roser , Hong Phuc Vo , Rebecca Kantorek , Steven Seeger , Magdalena Rafecas

Gamma-ray bursts (GRBs) are among the most luminous transients in the Universe and constitute prime targets for multimessenger studies, particularly in connection with gravitational-wave events. The detection of very-high-energy (TeV)…

High Energy Astrophysical Phenomena · Physics 2026-05-26 Nissim Fraija , Jorge Alexis Montes , Sara Fraija-Castellanos , María Magdalena González

We describe the MERger-event Gamma-Ray (MERGR) Telescope intended for deployment by ~2021. MERGR will cover from 20 keV to 2 MeV with a wide field of view (6 sr) using nineteen gamma-ray detectors arranged on a section of a sphere. The…

Instrumentation and Methods for Astrophysics · Physics 2017-11-13 L. J. Mitchell , J. E. Grove , B. F. Phlips , C. C. Cheung , M. Kerr , R. S. Woolf , M. S. Briggs , J. S. Perkins

Gamma-ray bursts (GRBs) are among the most energetic transient phenomena in the universe and serve as powerful probes for high-energy astrophysical processes. In particular, faint GRBs originating from a distant universe may provide unique…

Computer Vision and Pattern Recognition · Computer Science 2026-02-20 Shogo Sato , Kazuo Tanaka , Shojun Ogasawara , Kazuki Yamamoto , Kazuhiko Murasaki , Ryuichi Tanida , Jun Kataoka

This contribution outlines the implementation of the matrix element method (MEM) in the search for $\text{t}\bar{\text{t}}$H, H $\rightarrow \text{b}\bar{\text{b}}$ events. In particular, the evaluation of the transfer functions, which…

High Energy Physics - Experiment · Physics 2018-12-21 Maren Meinhard

Compton scattering of photons off high-energy electrons is a fundamental quantum mechanical process widely utilized to produce a $\gamma$-ray beam for scientific research. Instead of injecting laser light into a storage ring as a…

A considerable fraction of incident high-energy photons from astrophysical transients such as Gamma-Ray Bursts (GRBs) is Compton scattered by the Earth's atmosphere. These photons, sometimes referred to as the "reflection component",…

High Energy Astrophysical Phenomena · Physics 2021-05-21 Sourav Palit , Akash Anumarlapudi , Varun Bhalerao

Modern cosmological analyses constrain physical parameters using Markov Chain Monte Carlo (MCMC) or similar sampling techniques. Oftentimes, these techniques are computationally expensive to run and require up to thousands of CPU hours to…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-25 Thomas McClintock , Eduardo Rozo

The detection of photons with energies greater than a few tenths of an MeV, interacting via Compton scattering and/or pair production, faces a number of difficulties. The reconstruction of single-scatter Compton events can only determine…

Instrumentation and Methods for Astrophysics · Physics 2023-04-05 Denis Bernard , Stanley D. Hunter , Toru Tanimori

Extreme weather events epitomize high cost: to society through their physical impacts, and to computer servers that simulate them to assess risk and advance physical understanding. It costs hundreds of simulation years to sample a few…

Atmospheric and Oceanic Physics · Physics 2026-04-14 Justin Finkel , Paul A. O'Gorman

This paper presents a computation method of generalized scattering matrix (GSM) based on integral equations and the method of moments (MoM), specifically designed for antennas excited through waveguide ports. By leveraging two distinct…

Signal Processing · Electrical Eng. & Systems 2025-07-18 Chenbo Shi , Jin Pan , Xin Gu , Shichen Liang , Le Zuo

The recent discovery of gravitational waves from GW170817, associated with a short Gamma-Ray Burst (GRB) at a distance of $40$Mpc, has demonstrated that short GRBs can occur locally and at a reasonable rate. Furthermore, gravitational waves…

High Energy Astrophysical Phenomena · Physics 2018-05-08 Paz Beniamini , Dimitrios Giannios , George Younes , Alexander J. van der Horst , Chryssa Kouveliotou

Large water Cherenkov detectors have shaped our current knowledge of neutrino physics and nucleon decay, and will continue to do so in the foreseeable future. These highly capable detectors allow for directional and topological, as well as…

High Energy Physics - Experiment · Physics 2022-02-04 Mo Jia , Karan Kumar , Liam S. Mackey , Alexander Putra , Cristovao Vilela , Michael J. Wilking , Junjie Xia , Chiaki Yanagisawa , Karan Yang

The principal paradigm for the prompt emission of gamma-ray bursts invokes diffusive acceleration at shocks internal to the dynamic ultrarelativistic outflow. This paper explores expectations for burst emission spectra arising from shock…

Astrophysics · Physics 2009-11-10 Matthew G. Baring , Matthew L. Braby