Detection of B-Mode Polarization at Degree Angular Scales by BICEP2
Detection of B-Mode Polarization at Degree Angular Scales by BICEP2
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DOI：
10.1103/physrevlett.112.241101
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发表时间：
2014-06-19
影响因子：
8.6
通讯作者：
Yoon, K. W.
中科院分区：
文献类型：
--
作者：
Ade, P. A. R.;Aikin, R. W.;Yoon, K. W.
我们报告了BICEP2实验的结果，这是一种宇宙微波背景（CMB）偏光仪，专门设计用于搜索B围绕L的B模式功率谱中的通货膨胀引力波的信号，类似于80。配备有512个天线耦合过渡边缘传感器150 GHz钢计的焦平面的折射光系统，每个光学系统温度敏感性近似于300 mu k-cmb root s。从2010年到2012年，从南极从南极观察到了三个季节。在Stokes Q和U中观察到一个低前景的天空区域，其有效面积为380平方摄氏度，深度为87 nk deg。观察，数据减少，地图，模拟和结果。我们发现在30 <l <150的范围内，基础透镜-ACDM预期的B模式过量过量，与无效假设不一致，其显着性> 5 sigma。通过基于详细的校准测量值的折刀测试和模拟，我们表明系统污染比观察到的过量小得多。与WMAP 23 GHz地图的交叉相关性，我们发现银河同步子对观察到的信号的贡献可忽略不计。我们还检查了许多可用的极化灰尘发射模型，并发现在其默认参数值下，它们预测的功率类似于（5-10）x比观察到的过量信号小（与我们的地图没有显着的互相关）。但是，这些模型不受外部公共数据的充分限制，以排除足够明亮的灰尘发射以解释整个多余信号的可能性。与二头肌实验的100 GHz图相关的二头肌相关，确认过量信号具有3个Sigma的意义，并且发现其光谱指数与CMB的频谱指数一致，在1.7 Sigma时不利于灰尘。观察到的B模式功率谱非常适合具有张量与尺度比率r = 0.20（-0.05）（ + 0.07）的镜头-ACDM +张量理论模型，r = 0在7.0 Sigma时不利。考虑到前景的贡献，灰尘将通过即将到来的数据集更好地限制这一价值的数量将其向下移动。
We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around l similar to 80. The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor 150 GHz bolometers each with temperature sensitivity of approximate to 300 mu K-CMB root s. BICEP2 observed from the South Pole for three seasons from 2010 to 2012. A low-foreground region of sky with an effective area of 380 square deg was observed to a depth of 87 nK deg in Stokes Q and U. In this paper we describe the observations, data reduction, maps, simulations, and results. We find an excess of B-mode power over the base lensed-ACDM expectation in the range 30 < l < 150, inconsistent with the null hypothesis at a significance of > 5 sigma. Through jackknife tests and simulations based on detailed calibration measurements we show that systematic contamination is much smaller than the observed excess. Cross correlating against WMAP 23 GHz maps we find that Galactic synchrotron makes a negligible contribution to the observed signal. We also examine a number of available models of polarized dust emission and find that at their default parameter values they predict power similar to(5-10)x smaller than the observed excess signal (with no significant cross-correlation with our maps). However, these models are not sufficiently constrained by external public data to exclude the possibility of dust emission bright enough to explain the entire excess signal. Cross correlating BICEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3 sigma significance and its spectral index is found to be consistent with that of the CMB, disfavoring dust at 1.7 sigma. The observed B-mode power spectrum is well fit by a lensed-ACDM + tensor theoretical model with tensor-to-scalar ratio r = 0.20(-0.05)(+0.07), with r = 0 disfavored at 7.0 sigma. Accounting for the contribution of foreground, dust will shift this value downward by an amount which will be better constrained with upcoming data sets.