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Discovery of the linear energy dependence of the spectral lag of X-ray bursts from SGR J1935+2154.
- Source :
- Monthly Notices of the Royal Astronomical Society; Jun2023, Vol. 521 Issue 4, p5308-5333, 26p
- Publication Year :
- 2023
-
Abstract
- Spectral lag of the low-energy photons with respect to the high-energy ones is a common astrophysical phenomenon (such as gamma-ray bursts and the Crab Pulsar) and may serve as a key probe to the underlying radiation mechanism. However, spectral lag in keV range of the magnetar bursts has not been systematically studied yet. In this work, we perform a detailed spectral lag analysis with the Li et al.'s Cross-Correlation Function (Li-CCF) method for SGR J1935+2154 bursts observed by Insight - Hard X-ray Modulation Telescope (HXMT), Gravitational Wave High-energy Electromagnetic Counterpart All-sky Monitor (GECAM), and Fermi /Gamma-ray Burst Monitor (GBM) from 2014 July to 2022 January. We discover that the spectral lags of about 61 per cent (non-zero significance >1σ) bursts from SGR J1935+2154 are linearly dependent on the photon energy (E) with t <subscript>lag</subscript>(E) = α(E /keV) + C , which may be explained by a linear change of the temperature of the blackbody-emitting plasma with time. The distribution of the slope (α) approximately follows a Gaussian function with mean and standard deviation of 0.02 ms keV<superscript>−1</superscript> (i.e. high-energy photons arrive earlier) and 0.02 ms keV<superscript>−1</superscript>, respectively. We also find that the distribution can be well fitted with three Gaussians with mean values of ∼−10.009, 0.013, and 0.039 ms keV<superscript>−1</superscript>, which may correspond to different origins of the bursts. These spectral lag features may have important implications on the magnetar bursts. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00358711
- Volume :
- 521
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Monthly Notices of the Royal Astronomical Society
- Publication Type :
- Academic Journal
- Accession number :
- 163318358
- Full Text :
- https://doi.org/10.1093/mnras/stad885