Suzaku X-ray observation of the GK Persei dwarf nova outburst in 2015
Suzaku X-ray observation of the GK Persei dwarf nova outburst in 2015
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2015年GK英仙座矮新星爆发的朱雀X射线观测
DOI：
10.1093/mnras/stw734
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Manabu Ishida
中科院分区：
文献类型：
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作者：
Takayuki Yuasa;Takayuki Hayashi;Manabu Ishida
2015年3月至4月，中间极区的GK Per爆发了一次矮新星爆发。Suzaku X射线望远镜在为期四天的预定定点观测中偶然捕捉到了爆发的开始。在本文中，我们提出的时间和频谱分析结果的爆发，连同那些从档案数据的静态在2009年和2014年获得的。我们的时间分析证实了先前报道的在白色矮星（WD）的爆发中X射线计数率的自旋调制PWD = 351.4 ± 0.5 s。在硬X射线波段（16-60 keV）也能探测到这种调制，对吸收的光谱建模表明，这种调制被一种视线柱密度大于1023 cm −2的密集吸收所遮蔽。一个复杂的时间演化的自旋调制配置文件中看到的自旋最小相位从相位0.25在第一个半观测到0.65在第二个，和脉冲形状显着改变历元。在Fe K α带的光谱拟合揭示了荧光线等效宽度的增加，从0.80 eV（静止）到0.140 eV（爆发）。类He和类H Fe K α的等效宽度在两种状态下都是恒定的。在2-60 keV波段进行宽带光谱拟合，得到亚太阳Fe丰度为100.1 Z/cm，等离子体最高温度kTmax为50-60 keV。基于在6-7倍增大的吸积速率下温度变化很小的情况，讨论了爆发早期的吸积几何。
The intermediate polar GK Per exhibited a dwarf nova outburst in 2015 March–April.SuzakuX-ray telescope serendipitously captured the onset of the outburst during its pre-scheduled pointing observation spanning four days. In this paper, we present temporal and spectral analysis results of this outburst, together with those from archival data of quiescent obtained in 2009 and 2014. Our temporal analysis confirmed previously reported spin modulation of X-ray count rates in outburst with a white dwarf (WD) spin period ofPWD= 351.4 ± 0.5 s. The modulation is also detected in the hard X-ray band (16–60 keV), and spectral modelling of the absorption suggests obscuration by a dense absorption with a line-of-sight column density ofNH> 1023cm−2. A complex time evolution of spin modulation profiles is seen; the spin minimum phase shifts from phase ∼0.25 in the first half of the observation to ∼0.65 in the second one, and the pulse shape significantly changes epoch by epoch. Spectral fitting in the Fe K α band revealed an increase of the fluorescent line equivalent width, from ∼80 eV (quiescent) to ∼140 eV (outburst). The equivalent widths of He-like and H-like Fe K α are consistent with being constant at ∼40 eV in the two states. Broad-band spectral fitting in the 2–60 keV band resulted in a sub-solar Fe abundance of ∼0.1 Z⊙and the maximum plasma temperaturekTmax∼ 50–60 keV when the isobaric cooling-flow model was applied. Based on the very small temperature change against a 6–7 times increased accretion rate, the accretion geometry in early outburst is discussed.