THE ATACAMA COSMOLOGY TELESCOPE: BEAM MEASUREMENTS AND THE MICROWAVE BRIGHTNESS TEMPERATURES OF URANUS AND SATURN
THE ATACAMA COSMOLOGY TELESCOPE: BEAM MEASUREMENTS AND THE MICROWAVE BRIGHTNESS TEMPERATURES OF URANUS AND SATURN
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阿塔卡马宇宙学望远镜：天王星和土星的光束测量和微波亮度温度
DOI：
10.1088/0067-0049/209/1/17
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Edward J. Wollack
中科院分区：
文献类型：
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作者：
M. Hasselfield;K. Moodley;J. Bond;Sudeep Das;M. Devlin;J. Dunkley;R. Dunner;J. Fowler;P. Gallardo;M. Gralla;A. Hajian;M. Halpern;A. Hincks;T. Marriage;D. Marsden;M. Niemack;M. Nolta;L. Page;B. Partridge;B. Schmitt;N. Sehgal;J. Sievers;S. Staggs;D. Swetz;E. Switzer;Edward J. Wollack
我们描述了阿塔卡马宇宙学望远镜 (ACT) 的光束轮廓和窗口函数的测量，该望远镜于 2007 年至 2010 年期间使用千像素测辐射热计阵列，中心频率为 148、218 和 277 GHz。土星图用于测量每个阵列和每个观测季节的光束形状。以保留光束不确定性的空间相关性的方式将径向轮廓变换到傅立叶空间，以导出与角功率谱分析相关的窗函数。对所得的波束变换进行了多项校正，包括根据最终宇宙微波背景 (CMB) 测量图测量的经验校正，以考虑轻微的指向变化和对准误差的影响。在每个观测季节定期进行的天王星观测用于测量大气不透明度的影响并监测整个季节望远镜焦点的偏差。使用基于 WMAP 的 ACT 地图校准到 CMB 黑体，我们在 149 和 219 GHz 的有效频率下获得了天王星和土星盘亮度温度的精确测量。对于天王星，我们获得的热力学亮度温度为 106.7 ± 2.2 K 和 100.1 ± 3.1 K。对于土星，我们使用简单模型对光环不透明度和发射的影响进行建模，并获得结果（无遮挡）盘温度 137.3 ± 3.2 K 和 137.3 ± 4.7 K。
We describe the measurement of the beam profiles and window functions for the Atacama Cosmology Telescope (ACT), which operated from 2007 to 2010 with kilopixel bolometer arrays centered at 148, 218, and 277 GHz. Maps of Saturn are used to measure the beam shape in each array and for each season of observations. Radial profiles are transformed to Fourier space in a way that preserves the spatial correlations in the beam uncertainty to derive window functions relevant for angular power spectrum analysis. Several corrections are applied to the resulting beam transforms, including an empirical correction measured from the final cosmic microwave background (CMB) survey maps to account for the effects of mild pointing variation and alignment errors. Observations of Uranus made regularly throughout each observing season are used to measure the effects of atmospheric opacity and to monitor deviations in telescope focus over the season. Using the WMAP-based calibration of the ACT maps to the CMB blackbody, we obtain precise measurements of the brightness temperatures of the Uranus and Saturn disks at effective frequencies of 149 and 219 GHz. For Uranus we obtain thermodynamic brightness temperatures 106.7 ± 2.2 K and 100.1 ± 3.1 K. For Saturn, we model the effects of the ring opacity and emission using a simple model and obtain resulting (unobscured) disk temperatures of 137.3 ± 3.2 K and 137.3 ± 4.7 K.