scholarly journals A new approach to modelling gamma-ray burst afterglows: using Gaussian processes to account for the systematics

2020 ◽  
Vol 497 (4) ◽  
pp. 4672-4683
Author(s):  
M D Aksulu ◽  
R A M J Wijers ◽  
H J van Eerten ◽  
A J van der Horst
Keyword(s):  
Gaussian Processes ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
New Approach ◽  
Radiative Processes ◽  
Microphysical Parameters ◽  
Propagation Effects ◽  
Recent Developments ◽  
Source Of Information ◽  
Over Time

ABSTRACT The afterglow emission from gamma-ray bursts (GRBs) is a valuable source of information to understand the physics of these energetic explosions. The fireball model has become the standard to describe the evolution of the afterglow emission over time and frequency. Because of recent developments in the theory of afterglows and numerical simulations of relativistic outflows, we are able to model the afterglow emission with realistic dynamics and radiative processes. Although the models agree with observations remarkably well, the afterglow emission still contains additional physics, instrumental systematics, and propagation effects that make the modelling of these events challenging. In this work, we present a new approach to modelling GRB afterglows, using Gaussian processes (GPs) to take into account systematics in the afterglow data. We show that, using this new approach, it is possible to obtain more reliable estimates of the explosion and microphysical parameters of GRBs. We present fit results for five long GRBs and find a preliminary correlation between the isotropic energetics and opening angles of GRBs, which confirms the idea of a common energy reservoir for the kinetic energy of long GRBs.

Erratum: A New Approach to Statistics of Cosmological Gamma‐Ray Bursts

2000 ◽  
Vol 536 (1) ◽  
pp. 513-513
Author(s):  
M. Bottcher ◽  
C. D. Dermer
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
New Approach

ALLEGRO: A new approach to gamma-ray bursts

1996 ◽  
Author(s):  
S. M. Matz ◽  
D. A. Grabelsky ◽  
W. R. Purcell ◽  
M. P. Ulmer ◽  
G. N. Pendleton ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
New Approach

scholarly journals WAVES ON NONCOMMUTATIVE SPACE–TIME AND GAMMA-RAY BURSTS

2000 ◽  
Vol 15 (27) ◽  
pp. 4301-4323 ◽  
Author(s):  
GIOVANNI AMELINO-CAMELIA ◽  
SHAHN MAJID
Keyword(s):  
Fourier Transform ◽  
Gamma Ray ◽  
Space Time ◽  
Gamma Ray Bursts ◽  
Noncommutative Space ◽  
Experimental Investigations ◽  
Cpt Violation ◽  
New Approach ◽  
Minkowski Space Time ◽  
Group Fourier Transform

Quantum group Fourier transform methods are applied to the study of processes on noncommutative Minkowski space–time [xi, t]=ιλxi. A natural wave equation is derived and the associated phenomena of in vacuo dispersion are discussed. Assuming the deformation scale λ is of the order of the Planck length one finds that the dispersion effects are large enough to be tested in experimental investigations of astrophysical phenomena such as gamma-ray bursts. We also outline a new approach to the construction of field theories on the noncommutative space–time, with the noncommutativity equivalent under Fourier transform to non-Abelianness of the "addition law" for momentum in Feynman diagrams. We argue that CPT violation effects of the type testable using the sensitive neutral-kaon system are to be expected in such a theory.

scholarly journals Recent developments in supernova research with VLBI

2013 ◽  
Vol 9 (S296) ◽  
pp. 53-57 ◽  
Author(s):  
Norbert Bartel ◽  
Michael F. Bietenholz
Keyword(s):  
Very Long Baseline Interferometry ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Expansion Velocity ◽  
Radial Density ◽  
Density Profiles ◽  
Long Baseline ◽  
Vlbi Observations ◽  
Recent Developments ◽  
Circumstellar Medium

AbstractVery long baseline interferometry (VLBI) observations during the last 30 years have resolved many supernovae and provided detailed measurements of the expansion velocity and deceleration. Such measurements are useful for estimating the radial density profiles of both the ejecta and the circumstellar medium left over from the progenitor. VLBI measurements are also the most direct way of confirming the relativistic expansion velocities thought to occur in supernovae associated with gamma-ray bursts. Well-resolved images of a few supernovae have been obtained, and the interaction of the ejecta as it expands into the circumstellar medium could be monitored in detail. We discuss recent results, for SN 1979C, SN 1986J, and SN 1993J, and note that updated movies of the latter two of the supernovae from soon after the explosion to the present are available from the first author's personal website.

scholarly journals A New Approach to Statistics of Cosmological Gamma‐Ray Bursts

2000 ◽  
Vol 529 (2) ◽  
pp. 635-643 ◽  
Author(s):  
M. Bottcher ◽  
C. D. Dermer
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
New Approach

scholarly journals GRAVITATIONAL LENSING OF COSMOLOGICAL NEUTRINO SOURCES

2011 ◽  
Vol 03 ◽  
pp. 475-481
Author(s):  
GUSTAVO E. ROMERO ◽  
FLORENCIA L. VIEYRO
Keyword(s):  
Black Holes ◽  
Gravitational Lensing ◽  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
First Stars ◽  
The Earth ◽  
Source Of Information ◽  
The Universe ◽  
Expected Signal

Long gamma-ray bursts are likely the result of the collapse of very massive stars into black holes. These events are expected to produce high-energy neutrinos through photomeson production. Such neutrinos can escape from the source and travel up to the Earth. In the case of Population III progenitors for gamma-ray bursts, the neutrinos can be the only source of information of the first stars formed in the universe. The expected signal is rather weak, but we propose that gravitational lensing by nearby supermassive black holes can offer a natural tool to enhance and give a chance to detect neutrinos from the re-ionization era of the universe with current instrumentation.

scholarly journals Plasmas in Gamma-Ray Bursts: Particle Acceleration, Magnetic Fields, Radiative Processes and Environments

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 33
Author(s):  
Asaf Pe’er
Keyword(s):  
Particle Acceleration ◽  
Magnetic Fields ◽  
Light Curve ◽  
Gamma Ray ◽  
Broad Band ◽  
Gamma Ray Bursts ◽  
Magnetic Field Generation ◽  
Radiative Processes ◽  
Physical Problems ◽  
The One

Being the most extreme explosions in the universe, gamma-ray bursts (GRBs) provide a unique laboratory to study various plasma physics phenomena. The complex light curve and broad-band, non-thermal spectra indicate a very complicated system on the one hand, but, on the other hand, provide a wealth of information to study it. In this chapter, I focus on recent progress in some of the key unsolved physical problems. These include: (1) particle acceleration and magnetic field generation in shock waves; (2) possible role of strong magnetic fields in accelerating the plasmas, and accelerating particles via the magnetic reconnection process; (3) various radiative processes that shape the observed light curve and spectra, both during the prompt and the afterglow phases, and finally (4) GRB environments and their possible observational signature.

scholarly journals Introduction: recent developments in the study of gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1111-1118 ◽  
Author(s):  
Alan Wells ◽  
Ralph A.M.J Wijers ◽  
Martin J Rees
Keyword(s):  
Galaxy Formation ◽  
Massive Star ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Host Galaxies ◽  
First Stars ◽  
Local Environments ◽  
Recent Developments ◽  
Wave Emission ◽  
Very High

Gamma-ray bursts (GRBs) are immensely powerful explosions, originating at cosmological distances, whose outbursts persist for durations ranging from milliseconds to tens of seconds or more. In these brief moments, the explosions radiate more energy than the Sun will release in its entire 10 Gyr lifetime. Current theories attribute these phenomena to the final collapse of a massive star, or the coalescence of a binary system induced by gravity wave emission. New results from Swift and related programmes offer fresh understanding of the physics of GRBs, and of the local environments and host galaxies of burst progenitors. Bursts found at very high red shifts are new tools for exploring the intergalactic medium, the first stars and the earliest stages of galaxy formation. This Royal Society Discussion Meeting has brought together leading figures in the field, together with young researchers and students, to discuss and review the latest results from NASA's Swift Gamma-ray Burst Observatory and elsewhere, and to examine their impact on current understanding of the observed phenomena.

scholarly journals Photospheric emission in gamma-ray bursts

2017 ◽  
Vol 26 (10) ◽  
pp. 1730018 ◽  
Author(s):  
Asaf Pe’er ◽  
Felix Ryde
Keyword(s):  
Gamma Ray ◽  
Large Fraction ◽  
Indirect Evidence ◽  
Short Review ◽  
Gamma Ray Bursts ◽  
Thermal Component ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Recent Developments ◽  
Thermal Part

A major breakthrough in our understanding of gamma-ray bursts (GRB) prompt emission physics occurred in the last few years, with the realization that a thermal component accompanies the over-all nonthermal prompt spectra. This thermal part is important by itself, as it provides direct probe of the physics in the innermost outflow regions. It further has an indirect importance, as a source of seed photons for inverse-Compton scattering, thereby it contributes to the nonthermal part as well. In this short review, we highlight some key recent developments. Observationally, although so far it was clearly identified only in a minority of bursts, there is indirect evidence that a thermal component exists in a very large fraction of GRBs, possibly close to 100%. Theoretically, the existence of a thermal component has a large number of implications as a probe of underlying GRB physics. Some surprising implications include its use as a probe of the jet dynamics, geometry and magnetization.

Sign in / Sign up

Export Citation Format

Share Document