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相关论文: Likelihood Analysis of GRB Evolution with Redshift

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We studied the complete randomness of the angular distribution of gamma-ray bursts (GRBs) detected by BATSE. Since GRBs seem to be a mixture of objects of different physical nature we divided the BATSE sample into 5 subsamples (short1,…

天体物理学 · 物理学 2009-11-13 R. Vavrek , L. G. Balázs , A. Mészáros , I. Horváth , Z. Bagoly

The two leading interpretations of achromatic breaks that are observed in the light curves of GRBs afterglow are (i) the manifestation of the edge of a jet, which has a roughly uniform energy profile and a sharp edge and (ii) a line of…

天体物理学 · 物理学 2009-11-07 Rosalba Perna , Re'em Sari , Dale Frail

We introduce a new approach for decoupling trends (drift) and changepoints (shifts) in time series. Our locally adaptive model-based approach for robustly decoupling combines Bayesian trend filtering and machine learning based…

统计方法学 · 统计学 2024-01-09 Haoxuan Wu , Toryn L. J. Schafer , Sean Ryan , David S. Matteson

Photometric galaxy surveys constitute a powerful cosmological probe but rely on the accurate characterization of their redshift distributions using only broadband imaging, and can be very sensitive to incomplete or biased priors used for…

宇宙学与河外天体物理 · 物理学 2020-09-30 Alex Alarcon , Carles Sánchez , Gary M. Bernstein , Enrique Gaztañaga

Capturing aleatoric uncertainty is a critical part of many machine learning systems. In deep learning, a common approach to this end is to train a neural network to estimate the parameters of a heteroscedastic Gaussian distribution by…

机器学习 · 计算机科学 2022-04-04 Maximilian Seitzer , Arash Tavakoli , Dimitrije Antic , Georg Martius

In this work, our focus is on exploring the potential of current GRB measurements to provide reliable constraints on cosmological model parameters at high redshift. This work is divided into two parts. First, we calibrate the Amati relation…

宇宙学与河外天体物理 · 物理学 2023-07-10 Darshan Kumar , Nisha Rani , Deepak Jain , Shobhit Mahajan , Amitabha Mukherjee

We use a new method of analysis to determine parameters of cosmological gamma-ray bursts (GRBs), assuming that their distribution follows the star-formation history of the universe. Spectral evolution is calculated from an external shock…

天体物理学 · 物理学 2015-06-24 M. Boettcher , C. D. Dermer

We use high--quality, multi-band observations of Swift GRB120404A, from gamma-ray to radio frequencies, together with the new hydrodynamics code of van Eerten et al. (2012) to test the standard synchrotron shock model. The evolution of the…

Gamma-Ray Bursts (GRBs), being observed at high redshift (z = 9.4), vital to cosmological studies and investigating Population III stars. To tackle these studies, we need correlations among relevant GRB variables with the requirement of…

高能天体物理现象 · 物理学 2023-08-16 Maria G. Dainotti , Ritwik Sharma , Aditya Narendra , Delina Levine , Enrico Rinaldi , Agnieszka Pollo , Gopal Bhatta

We calculate the unseen-but-true GRB-event rate from a current flux-limited sample of 33 GRBs with individually measured redshifts. We consider a GRB-event rate which is proportional to the star-formation rate, in view of the GRB-SNe…

天体物理学 · 物理学 2009-11-10 Maurice H. P. M. van Putten , Tania Regimbau

Several correlations among Gamma-Ray Bursts (GRBs) quantities, both in the prompt and afterglow emissions, have been established during the last decades, thus enabling the standardization of GRBs as cosmological probes. Since GRBs are…

宇宙学与河外天体物理 · 物理学 2024-10-29 Giada Bargiacchi , Maria Giovanna Dainotti , Salvatore Capozziello

The duration distribution of 947 GRBs observed by $Swift$/BAT, as well as its subsample of 347 events with measured redshift, allowing to examine the durations in both the observer and rest frames, are examined. Using a maximum…

高能天体物理现象 · 物理学 2016-01-29 Mariusz Tarnopolski

Change point analysis has become an important research topic in many fields of applications. Several research work has been carried out to detect changes and its locations in time series data. In this paper, a nonparametric method based on…

统计方法学 · 统计学 2017-11-28 Ramadha D. Piyadi Gamage , Wei Ning

Parameter estimation in diffusion processes from discrete observations up to a first-hitting time is clearly of practical relevance, but does not seem to have been studied so far. In neuroscience, many models for the membrane potential…

概率论 · 数学 2014-03-06 Enrico Bibbona , Susanne Ditlevsen

Clustering methods are an important tool to enumerate and describe the different coherent kinds of Gamma Ray Bursts (GRBs). But their performance can be affected by a number of factors such as the choice of clustering algorithm and inherent…

高能天体物理现象 · 物理学 2017-06-13 Souradeep Chattopadhyay , Ranjan Maitra

Mixture models are a popular tool in model-based clustering. Such a model is often fitted by a procedure that maximizes the likelihood, such as the EM algorithm. At convergence, the maximum likelihood parameter estimates are typically…

统计计算 · 统计学 2019-07-23 Adrian O'Hagan , Thomas Brendan Murphy , Luca Scrucca , Isobel Claire Gormley

While many real-world data streams imply that they change frequently in a nonstationary way, most of deep learning methods optimize neural networks on training data, and this leads to severe performance degradation when dataset shift…

机器学习 · 计算机科学 2021-07-02 Wonju Lee , Seok-Yong Byun , Jooeun Kim , Minje Park , Kirill Chechil

We test the correlation found by Reichart et al. (2001) between time variability and peak luminosity of Gamma-Ray Bursts (GRBs). Recently Guidorzi et al. (2005) found that this still holds for a sample of 32 GRBs with spectroscopic…

天体物理学 · 物理学 2007-08-29 Cristiano Guidorzi

The classification of events involving jets as signal-like or background-like can depend strongly on the jet algorithm used and its parameters. This is partly due to the fact that standard jet algorithms yield a single partition of the…

高能物理 - 唯象学 · 物理学 2015-06-15 Dilani Kahawala , David Krohn , Matthew D. Schwartz

We present the results of our systematic search for extended emission components following initial short gamma-ray burst (GRB) spikes, using Burst and Transient Source Experiment (BATSE) observations. We performed the extended emission…

高能天体物理现象 · 物理学 2013-01-17 Zahide Funda Bostanci , Yuki Kaneko , Ersin Gogus