J/ApJ/911/20 Power sp. density analysis of time series. II. (Tarnopolski+, 2021)
A comprehensive power spectral density analysis of astronomical time series.
II. The Swift/BAT long gamma-ray bursts.
Tarnopolski M., Marchenko V.
<Astrophys. J., 911, 20 (2021)>
=2021ApJ...911...20T 2021ApJ...911...20T
ADC_Keywords: GRB; Photometry; Redshifts
Keywords: Gamma-ray bursts ; Astrostatistics ; Astronomy data analysis ;
Light curves
Abstract:
We have investigated the prompt light curves of long gamma-ray bursts
(GRBs) from the Swift/BAT catalog. We aimed to characterize their
power spectral densities (PSDs), search for quasiperiodic oscillations
(QPOs), and conduct novel analyses directly in the time domain. We
analyzed the PSDs using Lomb-Scargle periodograms, and searched for
QPOs using wavelet scalograms. We also attempted to classify the GRBs
using the Hurst exponent, H, and the A-T plane. The PSDs fall into
three categories: power law (PL; P(f)∝1/fβ) with index
β∈(0,2), PL with a non-negligible Poisson noise level (PLC)
with β∈(1,3), and a smoothly broken PL (with Poisson noise
level) yielding high-frequency index β2∈(2,6). The latter
yields break timescales of the order of 1-100s. The PL and PLC models
are broadly consistent with fully developed turbulence, β=5/3.
For an overwhelming majority of GRBs (93%), H>0.5, implying ubiquity
of the long-term memory. We find no convincing substructure in the A-T
plane. Finally, we report on 34 new QPOs, with one or more constant
leading periods, as well as several chirping signals. The presence of
breaks and QPOs suggests the existence of characteristic timescales
that in at least some GRBs might be related to the dynamical
properties of plasma trajectories in the accretion disks powering the
relativistic jets.
Description:
The mask-weighted, background-subtracted light curves (LCs), in a 64ms
binning and covering the total energy range 15-350keV, were downloaded
from the Swift/BAT catalog (Lien+ 2016, J/ApJ/829/7). The portions of
the LCs within respective T100 intervals were extracted. We focus on
long gamma-ray bursts (GRBs) with a sufficient number of points to
conduct a meaningful time series and power spectral density (PSD)
analysis. We therefore utilized LCs with more than 50 points, i.e.,
with T100>3.2s. We excluded confirmed short GRBs with extended
emission. We ended with 1160 GRBs in our sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 147 1354 Time series and power spectral density (PSD)
properties of the gamma-ray bursts (GRBs)
table2.dat 81 34 Identified quasiperiodic oscillations (QPOs)
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See also:
J/ApJS/166/298 : Sp. cat. of bright BATSE gamma-ray bursts (Kaneko+, 2006)
J/MNRAS/431/3608 : BeppoSAX/GRBM and Fermi/GBM long GRBs (Dichiara+, 2013)
J/ApJ/777/132 : A search for progenitors of short GRBs (Dichiara+, 2013)
J/ApJS/211/13 : The second Fermi/GBM GRB catalog (4yr) (von Kienlin+, 2014)
J/A+A/589/A97 : GRBs Ep and Fourier PDS slope correlation (Dichiara+, 2016)
J/A+A/589/A98 : Swift GRBs individual power density sp. (Guidorzi+, 2016)
J/ApJ/829/7 : 3rd Swift/BAT GRB catalog (past ∼11yrs) (BAT3) (Lien+, 2016)
J/ApJ/867/131 : Blazar cand. behind the Magellanic Clouds (Zywucka+, 2018)
J/ApJ/896/20 : Swift BAT gamma-ray burst durations (Jespersen+, 2020)
J/ApJ/896/L20 : Swift BAT gamma-ray burst durations (Jespersen+, 2020)
J/ApJ/893/46 : The fourth Fermi-GBM GRB catalog: 10yrs (von Kienlin+, 2020)
http://swift.gsfc.nasa.gov/results/batgrbcat/ : Swift/BAT GRB online catalog
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/1354] Consecutive number of the GRB in
the sample (reverse chronological order)
6- 8 A3 --- --- [GRB]
9- 15 A7 --- GRB Identifying name of the GRB, according to
the Swift catalog
16 A1 --- --- [-]
17 I1 --- m_GRB ? Multiple index component on GRB140716A
(following the Swift catalog)
19- 25 F7.3 s T90 [0/811]? Duration of the GRB
27- 31 F5.2 --- betaPL [-0.3/2.1]? Exponent beta of the pure PL
fit
33- 36 F4.2 --- e_betaPL [0/0.06]? Uncertainty of the exponent beta
of the pure PL fit
38- 42 F5.2 --- betaPLC [0.4/12.4]? Exponent beta of the PL plus
Poisson noise (PLC) fit
44- 47 F4.2 --- e_betaPLC [0/7.3]? Uncertainty of the exponent beta
of the PL plus Poisson noise (PLC) fit
49- 53 F5.2 --- beta1SBPL [-7.8/1.91]? Low-frequency exponent beta1
of the SBPL fit
55- 58 F4.2 --- e_beta1SBPL [0/2.9]? Uncertainty of the low-frequency
exponent beta1 of the SBPL fit
60- 64 F5.2 --- beta2SBPL [0.98/15.32]? High-frequency exponent
beta2 of the SBPL fit
66- 69 F4.2 --- e_beta2SBPL [0/9.7]? Uncertainty of the high-frequency
exponent beta2 of the SBPL fit
71- 76 F6.2 s Tbreak [0.6/409]? Break time scale of the SBPL fit
78- 83 F6.2 s e_Tbreak [0.01/448]? Uncertainty of the break time
scale of the SBPL fit
85- 89 F5.2 s MVTS [0.17/61.1]? Minimum variability time scale
91- 95 F5.2 s e_MVTS [0/48]? Uncertainty of the minimum
variability time scale
97- 100 F4.2 --- H [0.09/0.95]? Hurst exponent
102- 105 F4.2 --- e_H [0.03/0.8]? Uncertainty of the Hurst
exponent
107- 110 F4.2 --- HPL [0/1]? Hurst exponent inferred from the
index betaPL
112- 115 F4.2 --- e_HPL [0/0.03]? Uncertainty of the Hurst
exponent inferred from the index betaPL
117- 121 F5.3 --- z [0.013/9.4]? Redshift
123- 129 F7.2 keV Epeak [32.7/4728]? Peak energy of the spectral
model
131- 136 F6.2 keV e_Epeak [1/918]? Uncertainty of the peak energy of
the spectral model
138- 142 F5.2 [10-7W] logLiso [49.8/54.2]? Logarithm of the peak
isotropic luminosity, erg/s
144- 147 F4.2 [10-7W] e_logLiso [0.01/0.3]? Uncertainty of the logarithm
of the peak isotropic luminosity
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [6/1335] Number as in Table 1
6- 8 A3 --- --- [GRB]
10- 16 A7 --- GRB GRB name
18- 56 A39 s Per Period(s) (1)
58- 79 A22 --- Comm Comment (2)
81 A1 --- f_Comm Flag on Comm (3)
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Note (1): Approximately constant leading periods are given with corresponding
uncertainties (indicated with the "±" sign). Period ranges of the
chirping signals are indicated with arrows, "->", showing the
direction of period evolution.
Note (2): For the harmonics, the closest integer ratios are provided.
Note (3): Flag as follows:
a = These high-order ratios might as well be spurious, or be obscured
due to uncertainties.
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History:
From electronic version of the journal
References:
Tarnopolski et al. Paper I. 2020ApJS..250....1T 2020ApJS..250....1T
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Oct-2022