Suzaku Observations of the Local and Distant Hot ISM
Suzaku Observations of the Local and Distant Hot ISM
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DOI：
10.1093/pasj/59.sp1.s141
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发表时间：
2006-09
影响因子：
2.3
通讯作者：
Randall K. Smith;M. Bautz;R. Edgar;K. Hamaguchi;J. Hughes;M. Ishida;R. Kelley;C. Kilbourne;K. Kuntz;D. McCammon;E. Miller;K. Mitsuda;K. Mukai;P. Plucinsky;F. Porter;R. Fujimoto;S. Snowden;Y. Takei;Y. Terada;Y. Tsuboi;N. Yamasaki
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文献类型：
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作者：
Randall K. Smith;M. Bautz;R. Edgar;K. Hamaguchi;J. Hughes;M. Ishida;R. Kelley;C. Kilbourne;K. Kuntz;D. McCammon;E. Miller;K. Mitsuda;K. Mukai;P. Plucinsky;F. Porter;R. Fujimoto;S. Snowden;Y. Takei;Y. Terada;Y. Tsuboi;N. Yamasaki
朱雀观测到分子云MBM 12和一个距离不到3光年的空白区域，以分离弥散软X射线背景的本地和远程分量。在接近MBM 12的地方，我们清楚地探测到了一条局部（D 275 pc）O VII发射线，强度为3.5光子cm −2 s −1 sr −1（或线单位LU），O VIII通量< 0.34 LU。这种O VII排放的起源可能是局部热泡（LHB）中的热气，日光层内与来自太阳风（SWCX）的氧离子的电荷交换，或两者兼而有之。如果完全来自LHB，则可以用一个辐射测量值为0.0075cm-6 pc，温度为1.2 ×10 6 K的区域来解释。然而，这种温度和发射测量意味着1/4 keV的发射超出了观测值。在X射线光变曲线或太阳风数据中，没有证据表明地冠SWCX有显著的贡献，尽管行星际SWCX仍然是可能的。在任何情况下，所观察到的O VII通量代表了LHB排放和行星际SWCX在这个方向上的上限。随后立即观察空白视野。在减去云上前景发射后，云外O VII和O VIII的净强度分别为2.34 ±0.33和0.77 ±0.16 LU。如果这个更遥远的O VII和O VIII辐射来自银河系盘外处于碰撞平衡的热等离子体，我们推断它的温度为（2.1 ±0.1）×10 6 K，辐射测量值为（4 ±0.6）×10 −3 cm −6 pc。
Suzaku observed the molecular cloud MBM 12 and a blank field less than 3 ◦ away to separate the local and distant components of the diffuse soft X-ray background. Towards MBM 12, a local (D 275pc) O VII emission line was clearly detected with an intensity of 3.5 photons cm −2 s −1 sr −1 (or line units, LU), and the O VIII flux was < 0.34 LU. The origin of this O VII emission could be hot gas in the Local Hot Bubble (LHB), charge exchange within the heliosphere with oxygen ions from the solar wind (SWCX), or both. If entirely from the LHB, the emission could be explained by a region with emission measure of 0.0075cm −6 pc and a temperature of 1.2 ×10 6 K. However, this temperature and emission measure implies 1/4 keV emission in excess of observations. There is no evidence in the X-ray light curve or solar wind data for a significant contribution from geocoronal SWCX, although interplanetary SWCX is still possible. In any case, the observed O VII flux represents an upper limit to both the LHB emission and interplanetary SWCX in this direction. The blank field was observed immediately afterwards. The net off-cloud O VII and O VIII intensities were (respectively) 2.34 ±0.33 and 0.77 ±0.16 LU, after subtracting the on-cloud foreground emission. If this more distant O VII and O VIII emission is from a thermal plasma in collisional equilibrium beyond the Galactic disk, we infer it has a temperature of (2.1 ±0.1) ×10 6 K with an emission measure of (4 ±0.6) ×10 −3 cm −6 pc.