Single-Pulse Gamma-Ray Bursts have Prevalent Hard-to-Soft Spectral Evolution

Fuente: arXiv
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Autores principales: Busby, Ian, Lazzati, Davide
Formato: Preprint
Publicado: 2024
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author Busby, Ian
Lazzati, Davide
author_facet Busby, Ian
Lazzati, Davide
contents We analyze the spectral evolution of 62 bright Fermi gamma-ray bursts with large enough signal to noise to allow for time resolved spectral analysis. We develop a new algorithm to test for single-pulse morphology that is insensitive to the specific shape of pulses. Instead, it only checks whether or not there are multiple, isolated, statistical significant peaks in the light curve. In addition, we carry out a citizen science test to assess light curve morphology and spectral evolution. We find that, no matter the adopted assessment method, bursts characterized by single-peaked prompt emission light curves have a greater tendency to also have a consistently decaying peak energy, or hard-to-soft spectral evolution. This contrasts the behavior of multi-peaked bursts, for which the tendency is to have a peak frequency that is not monotonically decreasing. We discuss this finding in the theoretical framework of internal/external shocks, and find it to be consistent with at least some single pulse bursts being associated with particularly high-density environments.
format Preprint
id arxiv_https___arxiv_org_abs_2407_12926
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Single-Pulse Gamma-Ray Bursts have Prevalent Hard-to-Soft Spectral Evolution
Busby, Ian
Lazzati, Davide
High Energy Astrophysical Phenomena
We analyze the spectral evolution of 62 bright Fermi gamma-ray bursts with large enough signal to noise to allow for time resolved spectral analysis. We develop a new algorithm to test for single-pulse morphology that is insensitive to the specific shape of pulses. Instead, it only checks whether or not there are multiple, isolated, statistical significant peaks in the light curve. In addition, we carry out a citizen science test to assess light curve morphology and spectral evolution. We find that, no matter the adopted assessment method, bursts characterized by single-peaked prompt emission light curves have a greater tendency to also have a consistently decaying peak energy, or hard-to-soft spectral evolution. This contrasts the behavior of multi-peaked bursts, for which the tendency is to have a peak frequency that is not monotonically decreasing. We discuss this finding in the theoretical framework of internal/external shocks, and find it to be consistent with at least some single pulse bursts being associated with particularly high-density environments.
title Single-Pulse Gamma-Ray Bursts have Prevalent Hard-to-Soft Spectral Evolution
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2407.12926