标题： NuSTAR在时钟爆发源GS 1826-24中发现一次长期类型-I X射线爆发 显示英文标题

标题： NuSTAR discovers a long type-I X-ray burst from the clocked burster GS 1826-24

摘要： 源GS~1826-24是一个中子星低质量X射线双星，因其极其规律的爆发行为而被称为“计时爆发现象”。我们报告了从该源检测到的一个长类型-I X射线爆发。我们对在2022年9月进行的NuSTAR观测中看到的持续时间为$\sim 600$秒的长X射线爆发进行了详细光谱分析。持续辐射很好地由一个吸收的热康普顿化模型（nthcomp）描述，并且在此观测期间源表现出硬光谱状态。观测到的爆发具有$\sim 25$秒的上升时间和$\sim 282$秒的衰减时间。爆发的时间分辨光谱显示出与纯热谱的显著偏离，并用一个变化温度的黑体加上一个演化的持续辐射组分模型来描述。我们在爆发期间观察到持续辐射的显著增强。爆发前持续通量的增强可能是由于庞廷-罗伯特森拖拽或日冕再处理所致。在爆发峰值时，黑体温度和黑体发射半径分别达到$2.10\pm 0.07$keV和$5.5\pm 2.1$km的最大值。 爆发期间的峰值通量（$F_{peak}$）为$\approx 2.4\times 10^{-8}$ ergs cm$^{-2}$ s$^{-1}$，这相当于光度为$\approx 9.7\times 10^{37}$ ergs s$^{-1}$。 显示英文摘要

摘要： The source GS~1826-24 is a neutron star low mass X-ray binary known as the 'clocked burster' because of its extremely regular bursting behavior. We report on the detection of a long type-I X-ray burst from this source. We perform a detailed spectroscopic analysis of the long X-ray burst, lasting for $\sim 600$ s, seen in the NuSTAR observation carried out on 2022 September. The persistent emission is well described by an absorbed thermal Comptonization model (nthcomp), and the source exhibits a hard spectral state during this observation. The observed burst exhibits a rise time of $\sim 25$ s and a decay time of $\sim 282$ s. The time-resolved spectroscopy of the burst shows a significant departure from a pure thermal spectrum and is described with a model consisting of a varying-temperature blackbody plus an evolving persistent emission component. We observe a significant enhancement in the persistent emission during the burst. The enhancement of the pre-burst persistent flux is possibly due to Poynting-Robertson drag or coronal reprocessing. At the peak of the burst, the blackbody temperature and the blackbody emitting radius reached a maximum of $2.10\pm 0.07$ keV and $5.5\pm 2.1$ km, respectively. The peak flux ($F_{peak}$) during the burst is $\approx 2.4\times 10^{-8}$ ergs cm$^{-2}$ s$^{-1}$, which corresponds to a luminosity of $\approx 9.7\times 10^{37}$ ergs s$^{-1}$.