标题： Suzaku观测到IGR J17391-3021发出的弱耀斑，代表了这种SFXT的常见低活动状态 显示英文标题

标题： Suzaku observes weak flares from IGR J17391-3021 representing a common low-activity state in this SFXT

摘要： 我们对使用 Suzaku 收集的对超大质量快速 X 射线瞬变源 IGR J17391-3021 (=XTE J1739-302) 的 37 千秒观测进行了分析。 该源从宁静状态演变为低活动水平，最终出现三个持续约 3 千秒的弱耀斑，其中峰值光度仅为预耀斑光度的 5 倍。 观测到的最低光度为 1.3x10^33 erg/s（d/2.7 kpc）^2，在 0.5--10 keV 范围内。 弱耀斑伴随着显著的光谱参数变化，包括柱密度（nH = (4.1+-0.5)x10^22 /cm^2），约为宁静期间测量的吸收值的 2--9 倍。 吸积遮挡的恒星风物质团可以解释这些小耀斑以及 nH 的增加。 将此次观测置于最近的 Swift 监测活动背景下，我们发现弱耀斑事件，或至少是高于宁静水平但远低于中等亮度或高光度爆发的增强活动时期，占所有 0.5--10 keV 能量范围观测的 60+-5% 以上，这使得这是 IGR J17391-3021 发射行为中最常见的状态。 显示英文摘要

摘要： We present an analysis of a 37-ks observation of the supergiant fast X-ray transient (SFXT) IGR J17391-3021 (=XTE J1739-302) gathered with Suzaku. The source evolved from quiescence to a low-activity level culminating in three weak flares lasting ~3 ks each in which the peak luminosity is only a factor of 5 times that of the pre-flare luminosity. The minimum observed luminosity was 1.3x10^33 erg/s (d/2.7 kpc)^2 in the 0.5--10 keV range. The weak flares are accompanied by significant changes in the spectral parameters including a column density (nH = (4.1+-0.5)x10^22 /cm^2) that is ~2--9 times the absorption measured during quiescence. Accretion of obscuring clumps of stellar wind material can explain both the small flares and the increase in nH. Placing this observation in the context of the recent Swift monitoring campaign, we find that weak-flaring episodes, or at least epochs of enhanced activity just above the quiescent level but well below the moderately bright or high-luminosity outbursts, represent more than 60+-5% of all observations in the 0.5--10keV energy range making this the most common state in the emission behavior of IGR J17391-3021