Ade P A R, Ahmed Z, Aikin R W, Alexander K D, Barkats D, Benton S J, Bischoff C A, Bock J J, Bowens-Rubin R, Brevik J A, Buder I, Bullock E, Buza V, Connors J, Crill B P, Duband L, Dvorkin C, Filippini J P, Fliescher S, Grayson J, Halpern M, Harrison S, Hilton G C, Hui H, Irwin K D, Karkare K S, Karpel E, Kaufman J P, Keating B G, Kefeli S, Kernasovskiy S A, Kovac J M, Kuo C L, Leitch E M, Lueker M, Megerian K G, Netterfield C B, Nguyen H T, O'Brient R, Ogburn R W, Orlando A, Pryke C, Richter S, Schwarz R, Sheehy C D, Staniszewski Z K, Steinbach B, Sudiwala R V, Teply G P, Thompson K L, Tolan J E, Tucker C, Turner A D, Vieregg A G, Weber A C, Wiebe D V, Willmert J, Wong C L, Wu W L K, Yoon K W
School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, United Kingdom.
Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
Phys Rev Lett. 2016 Jan 22;116(3):031302. doi: 10.1103/PhysRevLett.116.031302. Epub 2016 Jan 20.
We present results from an analysis of all data taken by the BICEP2 and Keck Array cosmic microwave background (CMB) polarization experiments up to and including the 2014 observing season. This includes the first Keck Array observations at 95 GHz. The maps reach a depth of 50 nK deg in Stokes Q and U in the 150 GHz band and 127 nK deg in the 95 GHz band. We take auto- and cross-spectra between these maps and publicly available maps from WMAP and Planck at frequencies from 23 to 353 GHz. An excess over lensed ΛCDM is detected at modest significance in the 95×150 BB spectrum, and is consistent with the dust contribution expected from our previous work. No significant evidence for synchrotron emission is found in spectra such as 23×95, or for correlation between the dust and synchrotron sky patterns in spectra such as 23×353. We take the likelihood of all the spectra for a multicomponent model including lensed ΛCDM, dust, synchrotron, and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r) using priors on the frequency spectral behaviors of dust and synchrotron emission from previous analyses of WMAP and Planck data in other regions of the sky. This analysis yields an upper limit r_{0.05}<0.09 at 95% confidence, which is robust to variations explored in analysis and priors. Combining these B-mode results with the (more model-dependent) constraints from Planck analysis of CMB temperature plus baryon acoustic oscillations and other data yields a combined limit r_{0.05}<0.07 at 95% confidence. These are the strongest constraints to date on inflationary gravitational waves.
我们展示了对BICEP2和凯克阵列宇宙微波背景（CMB）偏振实验在2014年观测季及之前所采集的所有数据进行分析的结果。这包括在95吉赫兹进行的首次凯克阵列观测。这些地图在150吉赫兹频段的斯托克斯Q和U中达到了50纳开尔文·度的深度，在95吉赫兹频段达到了127纳开尔文·度的深度。我们对这些地图与来自WMAP和普朗克的公开可用地图在23至353吉赫兹频率范围内进行了自谱和互谱分析。在95×150的B - B谱中，在适度显著性水平上检测到了超过透镜化ΛCDM模型的过量信号，这与我们之前工作中预期的尘埃贡献一致。在诸如23×95的谱中未发现同步辐射发射的显著证据，在诸如23×353的谱中也未发现尘埃与同步辐射天空模式之间的相关性证据。我们使用先前对WMAP和普朗克在天空其他区域数据的分析中尘埃和同步辐射发射的频率谱行为先验知识，对包括透镜化ΛCDM、尘埃、同步辐射以及来自暴胀引力波的可能贡献（由张量与标量比r参数化）的多分量模型计算所有谱的似然性。该分析在95%置信水平下得出上限r₀.₀₅ < 0.09，该上限对分析和先验知识中探索的变化具有鲁棒性。将这些B模式结果与普朗克对CMB温度加重子声学振荡及其他数据的分析（更多依赖模型）约束相结合，在95%置信水平下得出组合上限r₀.₀₅ < 0.07。这些是迄今为止对暴胀引力波最强的约束。
