Suzaku observations of Jovian diffuse hard X-ray emission
Suzaku observations of Jovian diffuse hard X-ray emission
复制标题
木星漫射硬 X 射线发射的朱雀观测
DOI：
10.1093/pasj/psab053
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发表时间：
2021
影响因子：
2.3
通讯作者：
Branduardi-Raymont Graziella
中科院分区：
文献类型：
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作者：
Numazawa Masaki;Ezoe Yuichiro;Ohashi Takaya;Ishikawa Kumi;Miyoshi Yoshizumi;Shiota Daikou;Uchiyama Yasunobu;Kimura Tomoki;Branduardi-Raymont Graziella
我们报告了对朱雀于2006年、2012年和2014年拍摄的三组木星x射线数据进行系统分析的结果。木星的弥漫性硬x射线发射是由朱雀在2006年发现的，当时太阳活动处于最低点。漫射发射在空间上与木星的内磁层一致，在光谱上符合平坦的幂律函数，表明非热发射。因此，假设木星内磁层中的超相对论（数十MeV）电子将太阳可见光光子逆复成x射线带。我们集中研究了木星漫射硬x射线辐射对太阳活动的依赖性，以验证这一设想。2012年和2014年的太阳活动处于第24太阳周期的最大值附近。通过对三个数据集的成像和光谱分析，我们成功地将漫射发射的贡献从木星的发射（即极光和圆盘发射）中分离出来。漫射发射的1-5 keV亮度是稳定的，没有明显的变化，并不仅仅依赖于太阳活动，太阳活动也几乎不影响木星内磁层的高能电子分布。相比之下，0.2-1和1-5 keV的体发射光度可能取决于太阳活动，并以2-5倍的倍数变化。这些结果有力地支持了超相对论电子的逆康普顿散射。本文根据Divine-Garrett模型估计了木星磁层高能电子的逆康普顿散射x射线的空间和光谱分布，并在x射线观测的内部区域（> 10RJ）内发现了可能的一致性。
We report on results of systematic analyses of the entire three X-ray data sets of Jupiter taken by Suzaku in 2006, 2012, and 2014. Jovian diffuse hard X-ray emission was discovered by Suzaku in 2006 when the solar activity went toward its minimum. The diffuse emission was spatially consistent with the Jovian inner magnetosphere and was spectrally fitted with a flat power-law function suggesting non-thermal emission. Thus, a scenario in which ultra-relativistic (tens of MeV) electrons in the Jovian inner magnetosphere inverse-Comptonize solar visible photons into X-ray bands has been hypothetically proposed. We focused on the dependence of the Jovian diffuse hard X-ray emission on the solar activity to verify this scenario. The solar activity in 2012 and 2014 was around the maximum of the 24th solar cycle. By combining the imaging and spectral analyses for the three data sets, we successfully separated the contribution of the diffuse emission from the emission of Jupiter’s body (i.e., the aurora and disk emission). The 1–5 keV luminosity of the diffuse emission has been stable and did not vary significantly, and did not simply depend on the solar activity, which is also known to affect the high-energy electron distribution in the Jovian inner magnetosphere scarcely. The luminosity of the body emission both in 0.2–1 and 1–5 keV, in contrast, probably depended on the solar activity and varied by a factor of 2–5. These results strongly supported the inverse-Compton scattering scenario by the ultra-relativistic electrons. In this paper, we estimate spatial and spectral distributions of the inverse-Compton scattering X-rays by Jovian magnetospheric high-energy electrons with reference to the Divine–Garrett model and found a possible agreement in an inner region (≲10RJ) for the X-ray observations.