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The multidimensional database of parameters thereby generated was investigated by principal component analysis, which revealed there is no evident correlation between the different parameters of the prompt emission and X-ray flares. Furthermore, the correlation studies revealed that while there is a trend of positive correlation between the minimum variability timescale of the flare and its duration, and of strong negative correlation with its peak flux, there are no such correlations observed in the prompt emission. Similarly, we find a positive correlation between the quiescent period and the flare duration, and a negative correlation with the flare peak flux, while no such correlations are observed for the prompt emission of the GRBs. Finally, among the X-ray flares, we find two dominant classes, whose variations are driven by the minimum variability timescale, peak flux, and fluence of the flares. 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引用次数: 0
摘要
Neil Gehrels Swift天文台的x射线望远镜进行了广泛的观测,揭示了与衰减余辉发射同时存在的晚时间耀斑。然而,这些耀斑的起源难以捉摸。本文利用2005-2020年快速伽玛射线暴(GRBs)观测的大型数据库,对瞬发伽玛射线发射与x射线耀斑之间的时间和光谱特性进行了系统的统计研究,包括持续时间、静止周期、峰值通量、通量、最小变率时间尺度和光谱幂律指数。通过主成分分析对生成的多维参数数据库进行了研究,结果表明,提示发射的不同参数与x射线耀斑之间没有明显的相关性。此外,相关研究表明,耀斑最小变率时间尺度与耀斑持续时间有正相关趋势,与耀斑峰值通量有很强的负相关趋势,而在瞬发期则没有这种相关性。同样,我们发现静止周期与耀斑持续时间呈正相关,与耀斑峰值通量呈负相关,而对于grb的快速发射则没有观察到这种相关性。最后,在x射线耀斑中,我们发现了两种主要的类型,它们的变化是由最小变异时间尺度、峰值通量和耀斑的影响驱动的。提出了表征瞬发和耀斑发射的这些不同参数的目录。
Statistical Analysis of Long GRBs’ Prompt Emission and X-Ray Flares: Multivariate Clustering and Correlations
Abstract The extensive observations done by the X-ray Telescope on board Neil Gehrels Swift Observatory have revealed the presence of late-time flares concurrent with the decaying afterglow emission. However, the origins of these flares are elusive. In this work, we make use of the large database of Swift observations (2005–2020) of long gamma-ray bursts (GRBs) to conduct a systematic statistical study between the prompt gamma-ray emission and X-ray flares by characterizing their temporal and spectral properties of duration, quiescent period, peak flux, fluence, minimum variability timescale, and spectral power-law index. The multidimensional database of parameters thereby generated was investigated by principal component analysis, which revealed there is no evident correlation between the different parameters of the prompt emission and X-ray flares. Furthermore, the correlation studies revealed that while there is a trend of positive correlation between the minimum variability timescale of the flare and its duration, and of strong negative correlation with its peak flux, there are no such correlations observed in the prompt emission. Similarly, we find a positive correlation between the quiescent period and the flare duration, and a negative correlation with the flare peak flux, while no such correlations are observed for the prompt emission of the GRBs. Finally, among the X-ray flares, we find two dominant classes, whose variations are driven by the minimum variability timescale, peak flux, and fluence of the flares. A catalog of these different parameters characterizing the prompt and flare emissions is presented.
期刊介绍:
The Astrophysical Journal Supplement (ApJS) serves as an open-access journal that publishes significant articles featuring extensive data or calculations in the field of astrophysics. It also facilitates Special Issues, presenting thematically related papers simultaneously in a single volume.