BICEP2 Collaboration, P. A. R. Ade, R. W. Aikin, D. Barkats, S. J. Benton, C. A. Bischoff, J. J. Bock, J. A. Brevik, I. Buder, E. Bullock, C. D. Dowell, L. Duba… 展开作者
BICEP2 Collaboration, P. A. R. Ade, R. W. Aikin, D. Barkats, S. J. Benton, C. A. Bischoff, J. J. Bock, J. A. Brevik, I. Buder, E. Bullock, C. D. Dowell, L. Duband, J. P. Filippini, S. Fliescher, S. R. Golwala, M. Halpern, M. Hasselfield, S. R. Hildebrandt, G. C. Hilton, K. D. Irwin, K. S. Karkare, J. P. Kaufman, B. G. Keating, S. A. Kernasovskiy, J. M. Kovac, C. L. Kuo, E. M. Leitch, M. Lueker, C. B. Netterfield, H. T. Nguyen, R. O'Brient, R. W. Ogburn, A. Orlando, C. Pryke, S. Richter, R. Schwarz, C. D. Sheehy, Z. K. Staniszewski, R. V. Sudiwala, G. P. Teply, J. E. Tolan, A. D. Turner, A. G. Vieregg, C. L. Wong, K. W. Yoon
In a companion paper we have reported a $>5σ$ detection of degree scale $B $-mode polarization at 150 GHz by the BICEP2 experiment. Here we provide a detailed study of potential instrumental systematic contamination to that measurement. We focus extensively on spurious polarization that can potentially arise from beam imperfections. We present a heuristic classification of beam imperfections according to their symmetries and uniformities, and discuss how resulting contamination adds or cancels in maps that combine observations made at multiple orientations of the telescope about its boresight axis. We introduce a technique, which we call "deprojection", for filtering the leading order beam-induced contamination from time ordered data, and show that it removes power from BICEP2's $BB$ spectrum consistent with predictions using high signal-to-noise beam shape measurements. We detail the simulation pipeline that we use to directly simulate instrumental systematics and the calibration data used as input to that pipeline. Finally, we present the constraints on $BB$ contamination from individual sources of potential systematics. We find that systematics contribute $BB$ power that is a factor $\sim10\times$ below BICEP2's 3-year statistical uncertainty, and negligible compared to the observed $BB$ signal. The contribution to the best-fit tensor/scalar ratio is at a level equivalent to $r=(3-6)\times10^{-3}$.
Impact of instrumental systematic errors on fine-structure constant measurements with quasar spectra
我们提出了一种新的“超校准”技术测量高分辨率光谱仪的波长尺度的系统失真。通过将“太阳双星”或小行星的光谱与参考实验室太阳光谱进行比较，可以在整个光学波长范围内，在两个中阶梯光栅级（$\sim$ 50- 100埃）和整个摄谱仪臂（$\sim$ 1000- 3000埃）的尺度上，以$\sim$ 10 m s $^{-1}$的精度跟踪标准钍-氩校准中的失真。使用档案光谱从过去的20年中，我们探讨了超校准的历史VLT-UVES和凯克-HIRES摄谱仪。我们发现，系统误差在他们的波长尺度是无处不在的和大量的，与通常的$\pm$ 200 m s $^{-1}$每1000 μ m之间变化的远程失真。我们应用一个简单的模型，这些扭曲模拟光谱的特点大UVES和HIRES类星体样品，以前表明可能的证据，宇宙学的变化，精细结构常数，$α$。在$α$的虚假偏差产生的模型密切匹配的重要方面的VLT-UVES类星体的结果在所有的红移和部分解释HIRES的结果，虽然不是自洽在所有的红移。也就是说，扭曲的明显普遍性、大小和一般特征能够显著削弱类星体吸收线中$α$变化的证据。
Addressing the Photometric Calibration Challenge: Explicit Determination of the Instrumental Response and Atmospheric Response Functions, and Tying it All Together
Large Interferometer For Exoplanets (LIFE): VII. Practical implementation of a five-telescope kernel-nulling beam combiner with a discussion on instrumental uncertainties and redundancy benefits
Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. III. Absolute Flux Calibration
