J/ApJ/898/14 GRB spectral properties from Fermi and Swift (Mao+, 2020)
Spectral diversities of gamma-ray bursts in high-energy bands: hints from
turbulent cascade.
Mao J., Li L., Wang J.
<Astrophys. J., 898, 14 (2020)>
=2020ApJ...898...14M 2020ApJ...898...14M
ADC_Keywords: GRB
Keywords: Gamma-ray bursts ; Magnetic fields ; Magnetohydrodynamics
Abstract:
We statistically examine the gamma-ray burst (GRB) photon indices
obtained by the Fermi-GBM and Fermi-LAT observations and compare the
LAT GRB photon indices to the GBM GRB photon indices. We apply the
jitter radiation to explain the GRB spectral diversities in the
high-energy bands. In our model, the jitter radiative spectral index
is determined by the spectral index of the turbulence. We classify
GRBs into three classes depending on the shape of the GRB high-energy
spectrum when we compare the GBM and LAT detections: the GRB spectrum
is concave (GRBs turn out to be softer and are labeled as S-GRBs), the
GRB spectrum is convex (GRBs turn out to be harder and are labeled as
H-GRBs), and the GRBs have no strong spectral changes (labeled as
N-GRBs). A universal Kolmogorov index 7/3 in the turbulent cascade is
consistent with the photon index of the N-GRBs. The S-GRB spectra can
be explained by the turbulent cascade due to the kinetic magnetic
reconnection with the spectral index range of the turbulence from 8/3
to 3.0. The H-GRB spectra originate from the inverse turbulent cascade
with the spectral index range of the turbulence from 2.0 to 3.5 that
occurred during the large lengthscale magnetic reconnection. Thus, the
GRB radiative spectra are diversified because the turbulent cascade
modifies the turbulent energy spectrum. More observational samples are
expected in the future to further identify our suggestions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 138 GRB spectral properties detected by Fermi-LAT,
Fermi-GBM, and Swift-BAT
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See also:
B/swift : Swift Master Catalog (HEASARC, 2004-)
J/ApJ/754/121 : GRBs from Fermi/GBM and LAT (The Fermi Team, 2012)
J/ApJ/787/90 : Gamma-ray bursts minimum timescales (Golkhou+, 2014)
J/ApJ/781/37 : Multi-band photometry of GRB 130427A (Perley+, 2014)
J/ApJS/211/13 : The second Fermi/GBM GRB catalog (4yr) (von Kienlin+, 2014)
J/ApJ/811/93 : Fermi/GBM GRB minimum timescales (Golkhou+, 2015)
J/ApJS/223/28 : The third Fermi/GBM GRB catalog (6yr) (Bhat+, 2016)
J/ApJ/829/7 : 3rd Swift/BAT GRB catalog (past ∼11yrs) (BAT3) (Lien+, 2016)
J/A+A/588/A135 : Fermi/GBM GRB time-resolved spectral catalog (Yu+, 2016)
J/ApJ/893/46 : 4rth Fermi-GBM GRB catalog: 10 years (von Kienlin+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB GRB Name
9- 12 A4 --- Class Classification (1)
14- 14 A1 --- Short Short GRB? *=yes
16- 20 F5.2 --- LAT1 [-4/-1] LAT photon index obtained from the
LAT observing time interval
22- 25 F4.2 --- e_LAT1 [0.04/2] Uncertainty in LAT1
27- 31 F5.2 --- LAT2 [-5.1/-1.5]? LAT photon index obtained from the
GBM observing time interval
33- 36 F4.2 --- e_LAT2 [0.05/2]? Uncertainty in LAT2
38- 42 F5.2 --- Beta [-4.7/-1.58]? Band function, high-energy photon
index
44- 48 F5.2 --- e_Beta [0.01/81.5]? Uncertainty in Beta
50- 54 F5.2 --- alpha [-1.58/0.08]? Band function, low-energy photon
index
56- 60 F5.2 --- e_alpha [0.0/34.7]? Uncertainty in alpha
62- 66 F5.2 10+2eV Epeak [0.19/42.5]? Peak energy
68- 72 F5.2 10+2eV e_Epeak [0.01/75.9]? Uncertainty in Epeak
74- 78 F5.2 --- PL [-2.02/-0.96]? BAT photon index, power-law
fitting
80- 83 F4.2 --- e_PL [0.02/0.58]? Uncertainty in PL
85- 89 F5.2 --- CPL [-1.8/-0.66]? BAT photon index, cutoff
power-law fitting
91- 94 F4.2 --- e_CPL [0.03/0.72]? Uncertainty in CPL
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Note (1): GRB classes with the capital letters of N, S, and H indicate
N-GRBs (GRBs have no strong spectral changes), S-GRBs (GRB spectrum is
concave and GRBs turn to be softer), and H-GRBs (GRB spectrum is convex
and GRBs turn to be harder), respectively. The numbers "1" and "2"
behind the letters indicate that the classification is based on the LAT
photon indices obtained from the LAT and GBM observing time intervals,
respectively.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Nov-2021