论文标题
首先看一下与阿尔玛的亚毫米太阳
A first look at the submillimeter Sun with ALMA
论文作者
论文摘要
我们介绍了第7个（0.86 mm; 347 GHz）中的Atacama大毫米/亚毫米阵列（ALMA）获得的第一个全盘太阳图像。尽管空间分辨率低（21英寸），但仍获得了几个有趣的结果。在我们的观察过程中，太阳实际上没有活跃的区域。磁盘上的安静太阳结构与大气成像组件（AIA）图像（AIA）图像（AIA）相似，在1600 A和304 A上，后者在Alma的分辨率上与先前的Alma分辨率相似，如先前未针对Band 6（1.26 MM）（3 MM）（1.2 MM）（MM）（3 MM）（MM）。 h $α$等效分辨率的图像。 $ t_b（\logμ_{100}）$，其中$μ_{100} $是降低到100 GHz的余弦。 6。更重要的是，$ t_b（\logμ_{100}）$曲线以$μ__{100} $的大值平坦，相应的$ t_e（\logτ_{100}）$在大$ $τ_{100} $上也可能是我们接近温度最小的。
We present the first full-disk solar images obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 7 (0.86 mm; 347 GHz). In spite of the low spatial resolution (21"), several interesting results were obtained. During our observation, the sun was practically devoid of active regions. Quiet Sun structures on the disk are similar to those in Atmospheric Imaging Assembly (AIA) images at 1600 A and 304 A, after the latter are smoothed to the ALMA resolution, as noted previously for Band 6 (1.26 mm) and Band 3 (3 mm) images; they are also similar to negative H$α$ images of equivalent resolution. Polar coronal holes, which are clearly seen in the 304 A band and small H$α$ filaments, are not detectable at 0.86 mm. We computed the center-to-limb variation (CLV) of the brightness temperature, $T_b$, in Band 7, as well as in Bands 6 and 3, which were obtained during the same campaign, and we combined them to a unique curve of $T_b(\logμ_{100})$, where $μ_{100}$ is the cosine of the heliocentric angle reduced to 100 GHz. Assuming that the absolute calibration of the Band 3 commissioning observations is accurate, we deduced a brightness temperature at the center of the disk of 6085 K for Band 7, instead of the value of 5500 K, extrapolated from the recommended values for Bands 3 and 6. More importantly, the $T_b(\logμ_{100})$ curve flattens at large values of $μ_{100}$, and so does the corresponding $T_e(\logτ_{100})$ at large $τ_{100}$. This is probably an indication that we are approaching the temperature minimum.
