MOIRCS Deep Survey. VI. Near-infrared Spectroscopy of K-Selected Star-forming Galaxies at z^~ 2
MOIRCS Deep Survey. VI. Near-infrared Spectroscopy of K-Selected Star-forming Galaxies at z^~ 2
复制标题
MOIRCS 深度调查。
DOI：
10.1088/0004-637x/718/1/11
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
T. et al.
中科院分区：
文献类型：
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作者：
Yoshikawa;T.;Ichikawa;T. et al.
我们提出了 EIS/Hinode 和 SUMER/SOHO 对极冕洞羽流间和羽流区域日冕线中检测到的传播扰动的观测结果。作为JOP196/HOP045计划的一部分，该观测于2007年11月13日进行。 SUMER 光谱观测提供有关辐射度波动以及已解析（多普勒频移）和未解析（多普勒宽度）视线速度的信息，而 EIS 40 英寸宽槽图像仅检测辐射度波动，但最大限度地提高了两个仪器之间重叠视场的概率。从距离-时间辐射图，我们检测到极地羽间区域存在传播波，周期为 15-20 分钟，传播速度从临边上方 130±14 km s− 1 增加到临边上方 160'' 左右的 330±140 km s− 1 。这些波可以追溯到冕洞盘上部分的明亮区域，传播速度在 25±1.3 至 38±4.5 km s−1 范围内，具有相同的周期性。这些磁盘上的明亮区域可以可视化为冠状漏斗的底部。相邻羽流区域也显示出存在具有相同周期性范围的传播扰动，但传播速度仅在 135±18 至 165±43 km s−1 范围内。两个区域的距离-时间辐射图之间的比较表明，羽流内的波在远离肢体的地方是不可观察到的（可能正在消散），而羽流间区域的情况并非如此。还进行了相关分析，以找出离肢区域几个高度处的振荡之间的时间延迟，发现结果与距离-时间图分析的结果一致。据我们所知，这一结果首次提供了靠近太阳的极地区域（1.2 R/R☉以内）传播扰动加速的光谱证据，这为理解这些波的起源提供了线索。我们认为，羽流区域中的波可能是阿尔夫波或快磁声波，而羽流区域中的波可能是慢磁声波。这可能会得出这样的结论：羽流间是快速太阳风加速的首选通道。
We present EIS/Hinode and SUMER/SOHO observations of propagating disturbances detected in coronal lines in inter-plume and plume regions of a polar coronal hole. The observation was carried out on 2007 November 13 as part of the JOP196/HOP045 program. The SUMER spectroscopic observation gives information about fluctuations in radiance and on both resolved (Doppler shift) and unresolved (Doppler width) line-of-sight velocities, whereas EIS 40''wide slot images detect fluctuations only in radiance but maximize the probability of overlapping field of view between the two instruments. From distance–time radiance maps, we detect the presence of propagating waves in a polar inter-plume region with a period of 15–20 minutes and a propagation speed increasing from 130±14 km s− 1 just above the limb to 330±140 km s− 1 around 160''above the limb. These waves can be traced to originate from a bright region of the on-disk part of the coronal hole where the propagation speed is in the range of 25±1.3 to 38±4.5 km s− 1, with the same periodicity. These on-disk bright regions can be visualized as the base of the coronal funnels. The adjacent plume region also shows the presence of propagating disturbances with the same range of periodicity but with propagation speeds in the range of 135±18 to 165±43 km s− 1 only. A comparison between the distance–time radiance map of the two regions indicates that the waves within the plumes are not observable (may be getting dissipated) far off-limb, whereas this is not the case in the inter-plume region. A correlation analysis was also performed to find out the time delay between the oscillations at several heights in the off-limb region, finding results consistent with those from the analysis of the distance–time maps. To our knowledge, this result provides first spectroscopic evidence of the acceleration of propagating disturbances in the polar region close to the Sun (within 1.2 R/R☉), which provides clues to the understanding of the origin of these waves. We suggest that the waves are likely either Alfvénic or fast magnetoacoustic in the inter-plume region and slow magnetoacoustic in the plume region. This may lead to the conclusion that inter-plumes are a preferred channel for the acceleration of the fast solar wind.