A Spectral Analysis of Fermi-LLE GRBs. (arXiv:1912.10587v1 [astro-ph.HE])

A Spectral Analysis of Fermi-LLE GRBs. (arXiv:1912.10587v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Duan_M/0/1/0/all/0/1">Ming-Ya Duan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_X/0/1/0/all/0/1">Xiang-Gao Wang</a>

The prompt emission of gamma-ray bursts remains mysterious since the
mechanism is difficult to understand even though there are much more
observations with the development of detection technology. But most of the
gamma-ray bursts spectra show the Band shape, which consists of the low energy
spectral index $alpha$, the high energy spectral index $beta$, the peak
energy $E_{p}$ and the normalization of the spectrum. We present a systematic
analysis of the spectral properties of 36 GRBs, which were detected by the
Gamma-ray Burst Monitor (GBM), simultaneously, were also observed by the Large
Area Telescope (LAT) and the LAT Low Energy (LLE) detector on the $Fermi$
satellite. We performed the detailed time-resolved spectral analysis for all of
the bursts in our sample. We found that the time-resolved spectrum at peak flux
can be well fitted by the empirical Band function for each burst in our sample.
Moreover, the evolution patterns of $alpha$ and $E_{p}$ have been carried for
statistical analysis, and the parameter correlations have been obtained such as
$E_{p}-F$, $alpha-F$, and $E_{p}- alpha$, all of them are presented by
performing the detailed time-resolved spectral analysis. We also demonstrated
that the two strong positive correlations $alpha-F$ and $E_{p}-alpha$ for
some bursts originate from a non-physical selection effects through simulation.

The prompt emission of gamma-ray bursts remains mysterious since the
mechanism is difficult to understand even though there are much more
observations with the development of detection technology. But most of the
gamma-ray bursts spectra show the Band shape, which consists of the low energy
spectral index $alpha$, the high energy spectral index $beta$, the peak
energy $E_{p}$ and the normalization of the spectrum. We present a systematic
analysis of the spectral properties of 36 GRBs, which were detected by the
Gamma-ray Burst Monitor (GBM), simultaneously, were also observed by the Large
Area Telescope (LAT) and the LAT Low Energy (LLE) detector on the $Fermi$
satellite. We performed the detailed time-resolved spectral analysis for all of
the bursts in our sample. We found that the time-resolved spectrum at peak flux
can be well fitted by the empirical Band function for each burst in our sample.
Moreover, the evolution patterns of $alpha$ and $E_{p}$ have been carried for
statistical analysis, and the parameter correlations have been obtained such as
$E_{p}-F$, $alpha-F$, and $E_{p}- alpha$, all of them are presented by
performing the detailed time-resolved spectral analysis. We also demonstrated
that the two strong positive correlations $alpha-F$ and $E_{p}-alpha$ for
some bursts originate from a non-physical selection effects through simulation.

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