J/ApJS/279/14 X-ray burst pulse obs. from GBM, GECAM & HXMT (Yang+, 2025)
Insights into the X-ray burst pulse morphology from SGR J1935+2154.
Yang J.-J., Xiao S., Wang Y., Xiong S.-L., Lin L., Jiang Z.-H.,
Liao T.-L., Li X.-B., Li C.-K., Yi S.-X., Zhang Z., Zhang S.-N.
<Astrophys. J. Suppl. Ser., 279, 14 (2025)>
=2025ApJS..279...14Y 2025ApJS..279...14Y
ADC_Keywords: Stars, neutron; X-ray sources; Gamma rays
Keywords: Magnetars
Abstract:
SGR J1935+2154 is an extremely active magnetar and the source of the
first fast radio burst in the Milky Way, characterized as a magnetar
X-ray burst, but whether the temporal features of this magnetar are
specific or not is not well known. Based on data from the Fermi
Gamma-ray Burst Monitor (GBM), Gravitational Wave High-energy
Electromagnetic Counterpart All-Sky Monitor (GECAM), and Hard X-ray
Modulation Telescope (HXMT), we investigate the temporal properties of
pulses and bursts, covering parameters such as the minimum variability
timescale (MVT), duration, rise/decay/waiting times, skewness,
peakedness, pulse width, and number of pulses. Except for the number
of pulses, all parameters follow the log-Gaussian distribution. In the
GBM and GECAM data, MVT and duration exhibit a negative correlation,
while the number of pulses and duration (or MVT) exhibit a positive
(or negative) correlation. Universal power-law relationships exist
among parameters, for example, rise time is positively correlated with
decay time, while decay/rise time (or width) and peakedness show a
negative correlation. We did not find a significant difference
compared with another magnetar, SGR J0501+4516. Finally, the
parameters observed by GBM and GECAM show no significant differences,
but some parameters observed by HXMT differ from both, suggesting that
they may originate from a different physical mechanism.
Description:
The Hard X-ray Modulation Telescope (HXMT), also known as
"Insight-HXMT", was launched in 2017 June. Its main payloads include
the High Energy X-ray Telescope (HE, energy range 20-250keV, time
resolution 2us), the Medium Energy X-ray Telescope (energy range
8-35keV, time resolution 6us) and the Low Energy X-ray Telescope
(energy range 1-10keV, time resolution 1ms). For this work, we select
the HE data with the highest temporal resolution.
The Gravitational Wave High-energy Electromagnetic Counterpart All-Sky
Monitor (GECAM) consists of four microsatellites specifically designed
to detect X-ray and gamma-ray radiation. GECAM-A/B was launched in
2020 December and operates on the same orbit; subsequently, GECAM-C
(also known as HEBS) was launched in 2022 October and GECAM-D (also
known as GTM) was launched in 2024 March.
The Fermi Gamma-ray Burst Monitor (GBM) is equipped with
14 scintillator detectors, including 12 sodium iodide (NaI) detectors
and two bismuth germanate (BGO) detectors, arranged in clusters around
the spacecraft. The NaI detectors cover an energy range from ∼8keV to
1MeV, while the BGO detectors cover ∼200keV to 30MeV.
We collected data from Fermi-GBM, GECAM, and Insight-HXMT from
2014-July to 2022-January. Fermi-GBM observed 580 bursts; GECAM, since
its launch in 2020 December, observed 103 bursts; and Insight-HXMT
observed 75 bursts during its dedicated pointing observation from
2020-April-28 to May-24. After removing the saturated bursts and
"timing glitches", we finally collected burst data from SGR J1935+2154
for HXMT, GECAM, and GBM, totaling 54, 103, and 554 bursts,
respectively. Since magnetar X-ray bursts (MXBs) are generally below
∼100keV, we focus on analyzing data within the energy range of 8-100keV.
Objects:
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RA (ICRS) DE Designation(s)
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19 34 55.67 +21 53 48.1 SGR J1935+2154 = NAME Sgr 1935+2154
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 165 1594 The fitting parameters of the magnetar X-ray burst
(MXB) pulses observed by different satellites
from SGR J1935+2154
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See also:
J/ApJ/744/141 : Shapes of GRB light curves (Bhat+, 2012)
J/ApJ/787/90 : Gamma-ray bursts minimum timescales (Golkhou+, 2014)
J/ApJ/901/L7 : NIR obs. of SGR 1935+215 with PGIR (De+, 2020)
J/ApJ/902/L43 : Fermi/GBM 2019 and 2020 bursts of SGR J1935+2154 (Lin+, 2020)
J/ApJ/904/L21 : NICER SGR1935+2154 burst & persistent emission (Younes+, 2020)
J/A+A/671/A112 : GRB minimum variability timescale (Camisasca+, 2023)
J/ApJ/953/67 : X-ray burst associated to FRB200428 (Ge+, 2023)
J/ApJS/271/19 : FGK dwarfs from LAMOST DR7 and Gaia DR3 and Kepler (Ye+, 2024)
J/ApJS/277/5 : GECAM obs. of SGR J1935+2154. I. Burst catalog (Xie+, 2025)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Sat Observatory code (1)
7- 16 A10 "Y/M/D" Obs.date UTC observation date
17 A1 --- --- [T]
18- 19 I2 h Obs.h UTC observation time, hour
20 A1 --- --- [:]
21- 22 I2 min Obs.m UTC observation time, minute
23 A1 --- --- [:]
24- 29 F6.3 s Obs.s UTC observation time, second
31- 32 I2 --- Seq [1/28] Pulse number
34- 40 F7.4 s RTime [0.0003/13.9] Rise time
42- 48 F7.4 s E_RTime [0.0004/29.5] Upper Uncertainty in RTime
50- 55 F6.4 s e_RTime [0.0002/8.5] Lower uncertainty in RTime
57- 64 F8.5 s DTime [0/12] Decay time
66- 73 F8.5 s E_DTime [0/33.3] Upper Uncertainty in DTime
75- 81 F7.5 s e_DTime [0/8.3] Lower uncertainty in DTime
83- 89 F7.4 s PTime [-0.5/0.98] Peak time
91- 96 F6.4 s E_PTime [0.0001/0.1] Upper Uncertainty in PTime
98-103 F6.4 s e_PTime [0.0001/0.07] Lower uncertainty in PTime
105-110 F6.3 --- Skew [0.002/49] Skewness
112-117 F6.3 --- E_Skew [0.004/34] Upper Uncertainty in Skew
119-124 F6.3 --- e_Skew [0.001/38] Lower uncertainty in Skew
126-129 F4.2 --- Peak [0.07/6.2] Peakedness
131-134 F4.2 --- E_Peak [0.04/5.5] Upper Uncertainty in Peak
136-139 F4.2 --- e_Peak [0.04/3.8] Lower uncertainty in Peak
141-144 F4.2 s Dur [0.01/1.4] Duration
146-151 F6.4 s MVT [0/0.3] Minimum Variability Timescale
153-158 F6.4 s E_MVT [0.0002/0.2] Upper Uncertainty in MVT
160-165 F6.4 s e_MVT [0/0.1] Lower uncertainty in MVT
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Note (1): Observatory code as follows:
GBM = Fermi-Gamma-ray Burst Monitor (1312 occurrences)
GECAM = Gravitational Wave High-energy Electromagnetic
Counterpart All-Sky Monitor (194 occurrences)
HXMT = Insight-Hard X-ray Modulation Telescope (88 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Feb-2026