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Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology

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A special issue of Galaxies (ISSN 2075-4434).

Deadline for manuscript submissions: 15 January 2025 | Viewed by 9808

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Special Issue Editors

Dr. Maria Giovanna Dainotti

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Guest Editor

Division of Science, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka 181-0015, Japan
Interests: gamma ray bursts; cosmology; machine learning

Prof. Dr. Nissim Fraija

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Guest Editor

Instituto de Astronomía, Universidad Nacional Autónoma de México, Circuito Exterior, C.U., A. Postal 70-264, Mexico City 04510, Mexico
Interests: gamma-ray burst theoretical modeling; gamma-ray burst; quasar cosmology; active galatic nuclei

Special Issue Information

Dear Colleagues,

GRBs are the most panchromatic and explosive phenomena in the Universe. After 50 years, still many theoretical models are challenged when they are compared to the variety of observational properties. We seek to better understand how theoretical models can be predictive of the observations, of the observational correlations and how we can possibly use GRBs as cosmological standard candles together with other probes. The investigation of these topics in the era of multimessenger astronomy aims to further enhance our understanding of these spectacular and still mysterious events.

Dr. Maria Giovanna Dainotti
Prof. Dr. Nissim Fraija
Guest Editors

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Published Papers (6 papers)

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Research

10 pages, 1402 KiB

Open AccessArticle

Calibration of Luminosity Correlations of Gamma-Ray Bursts Using Quasars

by Sarveshkumar Purohit and Shantanu Desai

Galaxies 2024, 12(6), 69; https://doi.org/10.3390/galaxies12060069 - 25 Oct 2024

Viewed by 496

Abstract

In order to test the efficacy of gamma-ray bursts (GRBs) as cosmological probes, we characterize the scatter in the correlations between six pairs of GRB observables. However, some of these observables depend on the luminosity distance, for which one needs to assume an underlying cosmological model. In order to circumvent this circularity problem, we use X-ray and UV fluxes of quasars as distance anchors to calculate the luminosity distance in a model-independent manner, which, in turn, is used to calculate the GRB-related quantities. We find that all six pairs of regression relations show high intrinsic scatter for both low- and high-redshift samples. This implies that these GRB observables cannot be used as model-independent high-precision cosmological probes. Full article

(This article belongs to the Special Issue Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology)

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17 pages, 712 KiB

Open AccessArticle

The Density and Ionization Profiles of Optically Dark and High-Redshift GRBs Probed by X-ray Absorption

by Eka Puspita Arumaningtyas, Hasan Al Rasyid, Maria Giovanna Dainotti and Daisuke Yonetoku

Galaxies 2024, 12(5), 51; https://doi.org/10.3390/galaxies12050051 - 28 Aug 2024

Viewed by 570

Abstract

The X-ray column density (

N_{HX}

The X-ray column density (

N_{HX}

) of gamma-ray bursts (GRBs) can probe the local environment of their progenitors over a wide redshift range. Previous work has suggested an increasing trend as a function of redshift. The relevance of this current analysis relies on investigating the selection bias method, such as the effect of the X-ray spectrum in high-redshift GRBs, which complicates the measurement of small

N_{HX}

; this has yet to be fully evaluated or discussed elsewhere. In this work, we evaluated these effects through simulations to define appropriate observational limits in the

N_{HX}

versus redshift plane. We then applied a one-sided nonparametric method developed by Efron and Petrosian. Within the framework of this method, we investigated the redshift dependence of

N_{HX}

and the local distribution function. Our results show that the evolution of

N_{HX}

with redshift firmly exists with a significance of more than four sigma and follows a power law of

{(1 + z)}^{1.39 (+ 0.22, - 0.27)}

. Based on these analyses and previous studies, the GRB progenitor mass varies but is more massive in the high-redshift environment and has a higher gas column density. This suggests that part of the luminosity evolution of GRBs, which has been widely reported, may be due to the evolution of the progenitor’s mass. Using the same method, we demonstrate that optically dark GRBs show a consistent evolution:

{(1 + z)}^{1.15 (+ 0.67, - 0.83)}

. By applying the Kolmogorov–Smirnov (KS) test, it is shown that optically dark GRBs have statistically identical flux and photon index distributions compared to normal GRBs, but the

N_{HX}

is systematically larger. This result suggests that the darkness of some GRB populations is not due to an intrinsic mechanism, but rather because a higher density surrounds them. Full article

(This article belongs to the Special Issue Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology)

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13 pages, 1478 KiB

Open AccessArticle

Enhancing Gamma-Ray Burst Detection: Evaluation of Neural Network Background Estimator and Explainable AI Insights

by Riccardo Crupi, Giuseppe Dilillo, Giovanni Della Casa, Fabrizio Fiore and Andrea Vacchi

Galaxies 2024, 12(2), 12; https://doi.org/10.3390/galaxies12020012 - 14 Mar 2024

Viewed by 1529

Abstract

The detection of Gamma-Ray Bursts (GRBs) using spaceborne X/gamma-ray photon detectors depends on a reliable background count rate estimate. This study focuses on evaluating a data-driven background estimator based on a neural network designed to adapt to various X/gamma-ray space telescopes. Three trials were conducted to assess the effectiveness and limitations of the proposed estimator. Firstly, quantile regression was employed to obtain an estimation with a confidence range prediction. Secondly, we assessed the performance of the neural network, emphasizing that a dataset of four months is sufficient for training. We tested its adaptability across various temporal contexts, identified its limitations and recommended re-training for each specific period. Thirdly, utilizing Explainable Artificial Intelligence (XAI) techniques, we delved into the neural network output, determining distinctions between a network trained during solar maxima and one trained during solar minima. This entails conducting a thorough analysis of the neural network behavior under varying solar conditions. Full article

(This article belongs to the Special Issue Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology)

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16 pages, 1217 KiB

Open AccessArticle

Parameter Inference of a State-of-the-Art Physical Afterglow Model for GRB 190114C

by Enrico Rinaldi, Nissim Fraija and Maria Giovanna Dainotti

Galaxies 2024, 12(1), 5; https://doi.org/10.3390/galaxies12010005 - 7 Feb 2024

Cited by 1 | Viewed by 1581

Abstract

A state-of-the-art semi-analytic gamma-ray burst (GRB) afterglow model with synchrotron self-Compton (SSC) emission has been applied for the first time for parameter inference using real GRB data. We analyzed the famous GRB 190114C as a case study. GRB 190114C, characterized by its long duration and high luminosity, was observed by many ground-based and orbiting telescopes spanning a wide range of electromagnetic wavelengths, from radio to GeV gamma rays. We used two advanced algorithms for inference: a nested sampling algorithm called UltraNest and an MCMC algorithm emcee. Evoking the standard afterglow model, the inference result and the best-fit values lead to an initial bulk Lorentz factor (a rough estimate of

Γ = 526

), which aligns with the values often seen in GRBs identified by the Fermi-LAT instrument. Similarly to the best-fit values of other studies in the literature, the derived values of microphysical parameters, the circumburst density, and the kinetic efficiency are consistent with those found after modeling the multi-wavelength observations in GRB 190114C. We show that the SSC from the forward-shock region can only describe the highest-energy photons above a few GeVs. Full article

(This article belongs to the Special Issue Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology)

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11 pages, 1240 KiB

Open AccessArticle

Holographic Quantum-Foam Blurring Is Consistent with Observations of Gamma-Ray Burst GRB221009A

by Eric Steinbring

Galaxies 2023, 11(6), 115; https://doi.org/10.3390/galaxies11060115 - 17 Nov 2023

Cited by 1 | Viewed by 2032

Abstract

Gamma-ray burst GRB221009A was of unprecedented brightness in the

γ

-rays and X-rays through to the far ultraviolet, allowing for identification within a host galaxy at redshift

z = 0.151

by multiple space and ground-based optical/near-infrared telescopes and enabling a first association—via cosmic-ray [...] Read more.

Gamma-ray burst GRB221009A was of unprecedented brightness in the

γ

-rays and X-rays through to the far ultraviolet, allowing for identification within a host galaxy at redshift

z = 0.151

by multiple space and ground-based optical/near-infrared telescopes and enabling a first association—via cosmic-ray air-shower events—with a photon of 251 TeV. That is in direct tension with a potentially observable phenomenon of quantum gravity (QG), where spacetime “foaminess” accumulates in wavefronts propagating cosmological distances, and at high-enough energy could render distant yet bright pointlike objects invisible, by effectively spreading their photons out over the whole sky. But this effect would not result in photon loss, so it remains distinct from any absorption by extragalactic background light. A simple multiwavelength average of foam-induced blurring is described, analogous to atmospheric seeing from the ground. When scaled within the fields of view for the Fermi and Swift instruments, it fits all

z \leq 5

GRB angular-resolution data of 10 MeV or any lesser peak energy and can still be consistent with the highest-energy localization of GRB221009A: a limiting bound of about 1 degree is in agreement with a holographic QG-favored formulation. Full article

(This article belongs to the Special Issue Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology)

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19 pages, 1666 KiB

Open AccessArticle

The Closure Relations in High-Energy Gamma-ray Bursts Detected by Fermi-LAT

by Maria Dainotti, Delina Levine, Nissim Fraija, Donald Warren, Peter Veres and Shashwat Sourav

Galaxies 2023, 11(1), 25; https://doi.org/10.3390/galaxies11010025 - 2 Feb 2023

Cited by 9 | Viewed by 2396

Abstract

Gamma-ray bursts (GRBs) are brief, intense pulses of high-energy emission associated with extreme astrophysical phenomena, e.g. the death of massive stars or the coalescence of compact objects. They have been observed at high energies by the Fermi Large Area Telescope (LAT), which detects GRBs in the 20 MeV–300 GeV energy range. The Fermi-LAT Second GRB Catalog (2FLGC) presents information on 186 GRBs observed from 2008 to 2018. We consider the GRBs that have been fitted in the 2FLGC with a broken (21 GRBs) or simple power law (65 GRBs), compiling a total sample of 86 GRBs. We analyze the relationship between the spectral and temporal indices using closure relations according to the synchrotron forward-shock model evolving in stratified environments (

n \propto r^{- k}

). We find that the model without energy injection is preferred over the one with energy injection. There is a clear preference for the cooling conditions

ν >

max{

ν_{c}, ν_{m}

} and

ν_{m} < ν < ν_{c}

(where

ν_{c}

and

ν_{m}

are the cooling and characteristic frequencies, namely the frequency at the spectral break). Within these cooling conditions, density profiles

r^{- k}

with values of

k = 1.5

and 2 generally have a higher rate of occurrence when considering relations with and without energy injection. Full article

(This article belongs to the Special Issue Gamma-Ray Bursts in Multiwavelength: Theory, Observational Correlations and GRB Cosmology)

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