Inhomogeneities in the light curves of gamma-ray bursts afterglow

Mazaeva, E.; Pozanenko, A.; Minaev, P. Yu.

doi:10.1142/s0218271818440121

Cited by 10 publications

(3 citation statements)

References 23 publications

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“…The sampling depends on the goal of investigation, and in case of GRB typical variability scale is about 0.1 s in the phase of prompt emission and seems to be independent of time since GRB trigger at the prompt phase (Mitrofanov et al 1998). The scale of variability increases linearly with time at the afterglow phase (e.g., (Mazaeva et al 2018)), so typical time sampling after tens minutes could be minute and it corroborates the necessity of exposure duration of about one minute to have a sufficient sampling.…”

Section: Discussionmentioning

confidence: 99%

IKI GRB-FuN: observations of GRBs with small-aperture telescopes

Volnova

Pozanenko

Mazaeva

et al. 2021

An. Acad. Bras. Ciênc.

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Gamma-ray bursts (GRBs) are the most energetic and mysterious events in the Universe, which are observed in all ranges of electromagnetic spectrum. Most valuable results about physics of GRB are obtained by optical observations. GRBs are initially detected in gamma-rays with poor localization accuracy, and an optical counterpart should be found. The faster the counterpart is found, the more it can give to physics. This first phase, as a rule, corresponds to an early afterglow. The next phases of the observations are multicolor photometry, polarimetry, spectroscopy, and few days later the search for a supernova or kilonova associated with the GRB, and finally, observations of the host galaxy. To manage the problem of fast optical observations, telescopes with a small aperture are suitable. They can have a large field of view, which is necessary to cover initial localizations of GRBs. The sensitivity of the telescope+detector may be sufficient to record statistically significant light curve with fine time resolution. We describe one of the networks of telescopes with a small aperture IKI-GRB FuN, and present the results of early optical observation of GRB sources, and discuss the design requirements of the optical observations for effective GRB research in the next decade.

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Section: Discussionmentioning

confidence: 99%

IKI GRB-FuN: observations of GRBs with small-aperture telescopes

Volnova

Pozanenko

Mazaeva

et al. 2021

An. Acad. Bras. Ciênc.

Self Cite

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“…This constraint on θ j corresponds to a beaming-corrected isotropic energy in the γ-ray band of E γ = E γ,iso (1 − cos θ j ) = 6.0 1.8 −0.5 × 10 51 erg (Chattopadhyay et al 2019). The study of the inhomogeneities in the optical light curves of GRB afterglows of Mazaeva et al (2018) shows that the early ( 0.5 d) optical afterglow of GRB 160131A is characterised by a broken power law with small-scale deviations (wiggles), followed a steep decay, suggestive of a jet break at t j = 1.2 ± 0.3 d.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Radio data challenge the broadband modelling of GRB 160131A afterglow

Marongiu

Guidorzi

Stratta

et al. 2022

A&A

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Context. Gamma-ray burst (GRB) afterglows originate from the interaction between the relativistic ejecta and the surrounding medium. Consequently, their properties depend on several aspects: radiation mechanisms, relativistic shock micro-physics, circumburst environment, and the structure and geometry of the relativistic jet. While the standard afterglow model accounts for the overall spectral and temporal evolution for a number of GRBs, its validity limits emerge when the data set is particularly rich and constraining, especially in the radio band. Aims. We aimed to model the afterglow of the long GRB 160131A (redshift z = 0.972), for which we collected a rich, broadband, and accurate data set, spanning from 6 × 108 Hz to 7 × 1017 Hz in frequency, and from 330 s to 160 days post-burst in time. Methods. We modelled the spectral and temporal evolution of this GRB afterglow through two approaches: (1) the adoption of empirical functions to model an optical/X-ray data set, later assessing their compatibility with the radio domain; and (2) the inclusion of the entire multi-frequency data set simultaneously through the Python package named SAGA (Software for AfterGlow Analysis), to obtain an exhaustive and self-consistent description of the micro-physics, geometry, and dynamics of the afterglow. Results. From deep broadband analysis (from radio to X-ray frequencies) of the afterglow light curves, GRB 160131A outflow shows evidence of jetted emission. Moreover, we observe dust extinction in the optical spectra, and energy injection in the optical/X-ray data. Finally, radio spectra are characterised by several peaks that could be due to either interstellar scintillation (ISS) effects or a multi-component structure. Conclusions. The inclusion of radio data in the broadband set of GRB 160131A makes a self-consistent modelling barely attainable within the standard model of GRB afterglows.

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“…This constrain on θ j corresponds to a beaming-corrected isotropic energy in the γ-ray band of E γ = E γ,iso (1 − cos θ j ) = 6.0 1.8 −0.5 × 10 51 erg, (Chattopadhyay et al 2019). The study of the inhomogeneities in the optical light curves of GRB afterglows of Mazaeva et al (2018) shows that the early ( 0.5 d) optical afterglow of GRB 160131A is characterised by a broken power-law with small scale deviations (wiggles), followed a steep decay, suggestive of a jet break at t j = 1.2 ± 0.3 d.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Radio data challenge the broadband modelling of GRB160131A afterglow

Marongiu,

Guidorzi,

Stratta

et al. 2021

Preprint

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Context. Gamma-ray burst (GRB) afterglows originate from the interaction between the relativistic ejecta and the surrounding medium. Consequently, their properties depend on several aspects: radiation mechanisms, relativistic shock micro-physics, circumburst environment, and the structure and geometry of the relativistic jet. While the standard afterglow model accounts for the overall spectral and temporal evolution for a number of GRBs, its validity limits emerge when the data set is particularly rich and constraining, especially in the radio band. Aims. We aimed to model the afterglow of the long GRB 160131A (redshift z = 0.972), for which we collected a rich, broadband, and accurate data set, spanning from 6 × 10 8 Hz to 7 × 10 17 Hz in frequency, and from 330 s to 160 days post burst in time. Methods. We modelled the spectral and temporal evolution of this GRB afterglow through two approaches: (1) the adoption of empirical functions to model optical/X-rays data set, later assessing their compatibility with the radio domain; (2) the inclusion of the entire multi-frequency data set simultaneously through the Python package named sAGa (Software for AfterGlow Analysis), to come up with an exhaustive and self-consistent description of the micro-physics, geometry, and dynamics of the afterglow. Results. From deep broadband analysis (from radio to X-ray frequencies) of the afterglow light curves, GRB 160131A outflow shows evidence of jetted emission. Moreover, we observe dust extinction in the optical spectra, and energy injection in the optical/X-ray data. Finally, radio spectra are characterised by several peaks, that could be due to either interstellar scintillation (ISS) effects or a multi-component structure. Conclusions. The inclusion of radio data in the broadband set of GRB 160131A makes a self-consistent modelling hardly attainable within the standard model of GRB afterglows.

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Inhomogeneities in the light curves of gamma-ray bursts afterglow

Cited by 10 publications

References 23 publications

IKI GRB-FuN: observations of GRBs with small-aperture telescopes

IKI GRB-FuN: observations of GRBs with small-aperture telescopes

Radio data challenge the broadband modelling of GRB 160131A afterglow

Radio data challenge the broadband modelling of GRB160131A afterglow

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