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We explore fitting gamma-ray burst spectra with three physically-motivated models, and thus revisit the viability of synchrotron radiation as the primary source of GRB prompt emission. We pick a sample of 100 bright GRBs observed by the…

High Energy Astrophysical Phenomena · Physics 2023-11-23 Suraj Poolakkil , Robert Preece , Peter Veres

Focal ratio degradation (FRD) is a major contributor to throughput and light loss in a fibre spectroscopic telescope system. We combine the guided mode theory in geometric optics and a well-known model, power distribution model (PDM), to…

Instrumentation and Methods for Astrophysics · Physics 2019-12-25 Yunxiang Yan , Gang Wang , Weimin Sun , A-Li Luo , Zhenyu Ma , Jian Li , Shuqing Wang

Observations of GRB afterglows ranging from radio to X-ray frequencies generate large data sets. Careful analysis of these broad-band data can give us insight into the nature of the GRB progenitor population by yielding such information…

Astrophysics · Physics 2009-11-07 E. Berger , R. Sari , D. A. Frail , S. R. Kulkarni

Fermi Gamma-ray Space Telescope has detected a diverse range of gamma-ray transients since its launch in 2008. Over the years, Fermi has accumulated an extensive public archive of transient events. Traditional classification methods for…

High Energy Astrophysical Phenomena · Physics 2026-03-31 Arpan Aryam John , Krushna Govind Shete , Shabnam Iyyani , Saptarshi Bej

This paper studies the application of the DDPG algorithm in trajectory-tracking tasks and proposes a trajectorytracking control method combined with Frenet coordinate system. By converting the vehicle's position and velocity information…

Robotics · Computer Science 2024-11-22 Tongzhou Jiang , Lipeng Liu , Junyue Jiang , Tianyao Zheng , Yuhui Jin , Kunpeng Xu

Gamma-ray bursts (GRBs) can be classified with their linearly dependent parameters alongside the standard $T_{90}$ distribution. The Generalized linear mixture model(GLM) identifies the number of linear dependencies in a two-parameter…

High Energy Astrophysical Phenomena · Physics 2023-05-10 Sourav Dutta , Sunanda , Reetanjali Moharana , Manish Kumar

A non-intrusive model order reduction (MOR) method that combines features of the dynamic mode decomposition (DMD) and the radial basis function (RBF) network is proposed to predict the dynamics of parametric nonlinear systems. In many…

Infrared small target detection (ISTD) under complex backgrounds is a difficult problem, for the differences between targets and backgrounds are not easy to distinguish. Background reconstruction is one of the methods to deal with this…

Computer Vision and Pattern Recognition · Computer Science 2024-06-11 Jingchao Peng , Haitao Zhao , Kaijie Zhao , Zhongze Wang , Lujian Yao

We describe an efficient and exact method that enables global Bayesian analysis of cosmic microwave background (CMB) data. The method reveals the joint posterior density (or likelihood for flat priors) of the power spectrum $C_\ell$ and the…

Astrophysics · Physics 2009-11-10 Benjamin D. Wandelt , David L. Larson , Arun Lakshminarayanan

This theoretical work investigates different models to predict the redshift of Fast Radio Bursts (FRBs) from their observed dispersion measure (DM) and other reported properties. We performed an extensive revision of the FRBs with confirmed…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-13 Luz Ángela García , Eduard Piratova-Moreno , Felipe González-Alarcón , Jhonier Rangel

Gamma-ray bursts (GRBs) are ultra-relativistic collimated outflows, which emit synchrotron radiation throughout the entire electromagnetic spectrum when they interact with their environment. This afterglow emission enables us to probe the…

High Energy Astrophysical Phenomena · Physics 2022-02-09 M. D. Aksulu , R. A. M. J. Wijers , H. J. van Eerten , A. J. van der Horst

Aims: The effect of frequency-dependent AGN core positions (``core-shifts'') on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods: The basic equations relating to VLBI astrometry are…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 R. W. Porcas

This manuscript presents a multilevel analysis of gamma-ray bursts (GRBs). We focus on the plateau phase, which is often observed in the light curves (LCs) of GRBs. We discuss its observational properties and then thoroughly examine…

High Energy Astrophysical Phenomena · Physics 2025-04-09 Aleksander Ł. Lenart , Maria G. Dainotti , Nikita Khatiya , Dhruv Bal , Dieter H. Hartmann , Nissim Fraija , Bing Zhang

Although it has been widely discussed in video surveillance, background subtraction is still an open problem in the context of complex scenarios, e.g., dynamic backgrounds, illumination variations, and indistinct foreground objects. To…

Computer Vision and Pattern Recognition · Computer Science 2015-02-03 Liang Lin , Yuanlu Xu , Xiaodan Liang , Jianhuang Lai

Searching for fleeting radio transients like fast radio bursts (FRBs) with wide-field radio telescopes has become a common challenge in data-intensive science. Conventional algorithms normally cost enormous time to seek candidates by…

Instrumentation and Methods for Astrophysics · Physics 2025-12-23 Yao Chen , Rui Luo , Chen Wang , Yong-Kun Zhang , Shiqian Zhao , Chengbing Lyu , ZePeng Zheng , Hai Lei , DeJiang Zhou , Chenhui Niu , JinLin Han , George Hobbs , Di Li , Chengwei Liang , Siyi Tan , Ting Tian

HERMES (High Energy Rapid Modular Ensemble of Satellites) pathfinder is an in-orbit demonstration consisting of a constellation of six 3U nano-satellites hosting simple but innovative detectors for the monitoring of cosmic high-energy…

High Energy Astrophysical Phenomena · Physics 2023-09-06 Riccardo Crupi , Giuseppe Dilillo , Kester Ward , Elisabetta Bissaldi , Fabrizio Fiore , Andrea Vacchi

In this paper we examine gamma-ray and optical data of GRB 091024, a gamma-ray burst (GRB) with an extremely long duration of T90~1020 s, as observed with the Fermi Gamma-Ray Burst Monitor (GBM). We present spectral analysis of all three…

Cosmological models and their corresponding parameters are widely debated because of the current discrepancy between the results of the Hubble constant, $H_{0}$, obtained by SNe Ia, and the Planck data from the Cosmic Microwave Background…

High Energy Astrophysical Phenomena · Physics 2022-10-12 M. G. Dainotti , A. Ł. Lenart , A. Chraya , G. Sarracino , S. Nagataki , N. Fraija , S. Capozziello , M. Bogdan

An important concern in the application of gamma-ray bursts (GRBs) to cosmology is that the calibration of GRB luminosity/energy relations depends on the cosmological model, due to the lack of a sufficient low-redshift GRB sample. In this…

Astrophysics · Physics 2009-11-13 Nan Liang , Wei Ke Xiao , Yuan Liu , Shuang Nan Zhang

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