A First Comparison of Millimeter Continuum and Mg ii Ultraviolet Line Emission from the Solar Chromosphere
A First Comparison of Millimeter Continuum and Mg ii Ultraviolet Line Emission from the Solar Chromosphere
复制标题
DOI：
10.3847/2041-8213/aa844c
复制
发表时间：
2017-06
期刊：
影响因子：
--
通讯作者：
T. Bastian;G. Chintzoglou;B. De Pontieu;M. Shimojo;D. Schmit;J. Leenaarts;M. Loukitcheva
中科院分区：
文献类型：
--
作者：
T. Bastian;G. Chintzoglou;B. De Pontieu;M. Shimojo;D. Schmit;J. Leenaarts;M. Loukitcheva
我们目前的联合观测太阳的阿塔卡马大型毫米/亚毫米阵列（阿尔马）和接口区域成像光谱仪（IRIS）。毫米/亚毫米-λ连续谱发射和紫外线发射都来自太阳色球层，都有可能作为太阳大气这一神秘区域物理条件的强大和补充诊断。2015年12月18日，作为阿尔马科学验证工作的一部分，对太阳活动区进行了观测。太阳的连续辐射图是由阿尔马在1.25毫米（239千兆赫）波长处获得的。利用IRIS在2803.5 ° C获得了Mg ii h双峰线的同期图。虽然观察到1.25 mm亮度温度TB和Mg ii h线辐射温度Trad之间的明显相关性，但斜率<1，这可能是由于这些诊断对色球层的不同部分敏感以及Mg ii h线源函数包括散射分量的事实。平均TB（1.25 mm）和平均Trad（Mg ii）之间存在显著差异（35%）。分区的地图到"太阳黑子"，"安静的地区"，和"plage地区"，我们发现IRIS镁ii h线Trad和阿尔马TB区域依赖之间的关系。我们认为，这可能是区域依赖性的IRIS和阿尔马诊断和/或增加的程度之间的耦合的UV源功能和本地气体温度在更热，更密集的气体在plage地区的形成高度的结果。
We present joint observations of the Sun by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). Both millimeter/submillimeter-λ continuum emission and ultraviolet (UV) line emission originate from the solar chromosphere and both have the potential to serve as powerful and complementary diagnostics of physical conditions in this enigmatic region of the solar atmosphere. The observations were made of a solar active region on 2015 December 18 as part of the ALMA science verification effort. A map of the Sun’s continuum emission was obtained by ALMA at a wavelength of 1.25 mm (239 GHz). A contemporaneous map was obtained by IRIS in the Mg ii h doublet line at 2803.5 Å. While a clear correlation between the 1.25 mm brightness temperature TB and the Mg ii h line radiation temperature Trad is observed, the slope is <1, perhaps as a result of the fact that these diagnostics are sensitive to different parts of the chromosphere and that the Mg ii h line source function includes a scattering component. There is a significant difference (35%) between the mean TB (1.25 mm) and mean Trad (Mg ii). Partitioning the maps into “sunspot,” “quiet areas,” and “plage regions” we find the relation between the IRIS Mg ii h line Trad and the ALMA TB region-dependent. We suggest this may be the result of regional dependences of the formation heights of the IRIS and ALMA diagnostics and/or the increased degree of coupling between the UV source function and the local gas temperature in the hotter, denser gas in plage regions.