A MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND B-MODE POLARIZATION POWER SPECTRUM AT SUB-DEGREE SCALES WITH POLARBEAR
A MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND B-MODE POLARIZATION POWER SPECTRUM AT SUB-DEGREE SCALES WITH POLARBEAR
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DOI：
10.1088/0004-637x/794/2/171
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发表时间：
2014-10-20
影响因子：
4.9
通讯作者：
Zahn, O.
中科院分区：
文献类型：
--
作者：
Ade, P. A. R.;Akiba, Y.;Zahn, O.
本文报道了利用智利北极熊实验测量宇宙微波背景辐射B模偏振功率谱的结果。微弱的B模式偏振信号携带着关于宇宙引力结构形成的整个历史的信息，以及可能在非常早期的宇宙中发生的宇宙膨胀。我们的测量涵盖角多极范围500 < l < 2100，并且基于150 GHz下对25度（2）有效天空区域的观测，分辨率为3 '.5。在这些角度尺度上，宇宙中的介入结构对CMB的引力透镜作用预计是B模式偏振的主要来源。包括系统和统计的不确定性，没有B模式偏振功率的引力透镜的假设被拒绝在97.2%的置信度。带功率与标准宇宙学模型一致。将单个透镜振幅参数A（BB）拟合到测量的频带功率，A（BB）= 1.12 +/- 0.61（stat）（-0.12）（+0.04）（sys）+/- 0.07（multi），其中A（BB）= 1是基准wmap-9 λ CDM值。在这个表达式中，“stat”指的是统计不确定性，“sys”指的是与来自仪器和天体物理前景的可能偏差相关的系统不确定性，而“multi”指的是对测量振幅A（BB）具有倍增效应的校准不确定性。
We report a measurement of the B-mode polarization power spectrum in the cosmic microwave background (CMB) using the Polarbear experiment in Chile. The faint B-mode polarization signature carries information about the universe's entire history of gravitational structure formation, and the cosmic inflation that may have occurred in the very early universe. Our measurement covers the angular multipole range 500 < l < 2100 and is based on observations of an effective sky area of 25 deg(2) with 3 '.5 resolution at 150 GHz. On these angular scales, gravitational lensing of the CMB by intervening structure in the universe is expected to be the dominant source of B-mode polarization. Including both systematic and statistical uncertainties, the hypothesis of no B-mode polarization power from gravitational lensing is rejected at 97.2% confidence. The band powers are consistent with the standard cosmological model. Fitting a single lensing amplitude parameter A(BB) to the measured band powers, A(BB) = 1.12 +/- 0.61(stat)(-0.12)(+0.04)(sys) +/- 0.07(multi), where A(BB) = 1 is the fiducial wmap-9 Lambda CDM value. In this expression, "stat" refers to the statistical uncertainty, "sys" to the systematic uncertainty associated with possible biases from the instrument and astrophysical foregrounds, and "multi" to the calibration uncertainties that have a multiplicative effect on the measured amplitude A(BB).