The removal method and generation mechanism of spikes in Insight-HXMT/HE telescope

Wu, Bai-Yang; Zhang, Yifei; Li, Xiaobo; Zhao, H. S.; Ge, Ming-Yu; Liu, Cong‐Zhan; Song, Liming; Qu, J. L.

doi:10.1007/s10686-022-09847-8

Cited by 4 publications

(4 citation statements)

References 12 publications

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“…We decided to start with ∆t = 64 ms and avoided a systematically research with finer resolution because preliminary attempts showed that the number of peak candidates was higher than expected, especially in the HXMT data. The reason behind this behaviour is the presence of sub-ms spikes caused by the electronics counting repeatedly the large signal deposited by energetic cosmic rays (Wu et al 2022). Whenever only (i) is fulfilled, we move to a finer time resolution (i.e., 4 ms and then 1 ms if necessary) and look for the same peak until both (i) and (ii) are satisfied; if (i) and (ii) are never satisfied, an upper limit on the FWHM min is taken from the finest timescale for which (i) is satisfied.…”

Section: Discussionmentioning

confidence: 99%

GRB minimum variability timescale with Insight-HXMT andSwift

Camisasca

Guidorzi

Amati³

et al. 2023

A&A

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Context. There has been significant technological and scientific progress in our ability to detect, monitor and model the physics of gamma-ray bursts (GRBs) over the 50 years since their first discovery. However, the dissipation process thought to be responsible for their defining prompt emission is still unknown. Recent efforts have focused on investigating how the ultrarelativistic jet of the GRB propagates through the progenitor's stellar envelope, for different initial composition shapes, jet structures, magnetisation, and -consequently -possible energy dissipation processes. Study of the temporal variability -in particular the shortest duration of an independent emission episode within a GRB -may provide a unique way to discriminate the imprint of the inner engine activity from geometry and propagation related effects. The advent of new high-energy detectors with exquisite time resolution now makes this possible. Aims. We aim to characterise the minimum variability timescale (MVT) defined as the shortest duration of individual pulses that shape a light curve for a sample of GRBs in the keV-MeV energy range and test correlations with other key observables, such as the peak luminosity, the Lorentz factor, and the jet opening angle. We compare these correlations with predictions from recent numerical simulations for a relativistic structured -possibly wobbling -jet and assess the value of temporal variability studies as probes of prompt-emission dissipation physics. Methods. We used the peak detection algorithm mepsa to identify the shortest pulse within a GRB time history and preliminarily calibrated mepsa to estimate the full width half maximum (FWHM) duration. We then applied this framework to two sets of GRBs:

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Section: Discussionmentioning

confidence: 99%

GRB minimum variability timescale with Insight-HXMT andSwift

Camisasca

Guidorzi

Amati³

et al. 2023

A&A

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“…The HE command hepical is also used to remove the spike events, which are caused by the interactions of high energy cosmic rays with satellite materials and usually occurred simultaneously in a few NaI and CsI detectors (Wu et al 2022). The ME command megrade is used to calculate the event grade and deadtime of each Field Programmable Gate Array (FPGA).…”

Section: Observation and Data Samplesmentioning

confidence: 99%

“…Spikes are short and soft pulses in the HE light curve caused by fake events output by the readout electronics when there is a very large energy deposition in HE detectors. The presence of spikes in the HE data is a well-known instrumental effect and has been studied in detail (Wu et al 2022).…”

Section: Burst Identificationmentioning

confidence: 99%

“…The spikes usually occur on only one or a few adjacent NaI and CsI detectors (see the right panel in Figure 3) with low energy events (i.e. the pulse height less than about channel 35) (Wu et al 2022), while the count increases of all non-blinded NaI detectors should be comparable for a SGR J1935+2154 burst (see the left panel in Figure 3) since the energy responses are similar for all nonblinded NaI detectors for the targeted source in the pointed observations. This is an important criterion to identify spikes.…”

Section: Burst Identificationmentioning

confidence: 99%

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Insight-HXMT dedicated 33-day observation of SGR J1935+2154 I. Burst Catalog

Cai,

Xue,

et al. 2022

Preprint

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Magnetars are neutron stars with extreme magnetic field and sometimes manifest as soft gamma-ray repeaters (SGRs). SGR J1935+2154 is one of the most prolific bursters and the first confirmed source of fast radio burst (i.e. FRB 200428). Encouraged by the discovery of the first X-ray counterpart of FRB, Insight-Hard X-ray Modulation Telescope (Insight-HXMT) implemented a dedicated 33-day long ToO observation of SGR

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Revisit the periodicity of SGR J1935+2154 bursts with updated sample

Xie

Cai

Xiong

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Since FRB 200428 has been found to be associated with an X-ray burst from the Galactic magnetar SGR J1935+2154, it is interesting to explore whether the magnetar bursts also follow the similar active periodic behaviour as some repeating FRBs. Previous studies show that there is possible period about 230 day in SGR J1935+2154 bursts. Here, we collected an updated burst sample from SGR J1935+2154, including all bursts reported by Fermi/GBM and GECAM till 2022 January. We also developed a targeted search pipeline to reveal more bursts from SGR J1935+2154 in the Fermi/GBM data from 2008 August to 2014 December (i.e. before the first burst detected by Swift/BAT). With this burst sample, we re-analyzed the possible periodicity of SGR J1935+2154 bursts using the Period Folding and Lomb-Scargle Periodogram methods. Our results show that the periodicity ∼238 day reported in literature is probably fake and the observation effects may introduce false periods (i.e. 55 day) according to simulation tests. We find that, for the current burst sample, the most probable period is 126.88±2.05 day, which could be interpreted as the precession of the magnetar. However, we note that the whole burst history is very complicated and difficult to be perfectly accommodated with any period reported thus far, therefore more monitoring observations of SGR J1935+2154 are required to test any periodicity hypothesis.

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The removal method and generation mechanism of spikes in Insight-HXMT/HE telescope

Cited by 4 publications

References 12 publications

GRB minimum variability timescale with Insight-HXMT andSwift

GRB minimum variability timescale with Insight-HXMT andSwift

Insight-HXMT dedicated 33-day observation of SGR J1935+2154 I. Burst Catalog

Revisit the periodicity of SGR J1935+2154 bursts with updated sample

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