Analysis of Temperature-to-Polarization Leakage in BICEP3 and Keck CMB Data from 2016 to 2018

• Published in: Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X
• Main Authors: Germaine, T.St., Ade, P.A.R., Ahmed, Z., Amiri, M., Barkats, D., Basu Thakur, R., Bischoff, C.A., Bock, J.J., Boenish, H., Bullock, E., Buza, V., IV, J.R. Cheshire, Connors, J.A., Cornelison, J., Crumrine, M., Cukierman, A., Denison, E., Dierickx, M., Duband, L., Eiben, M., Fatigoni, S., Filippini, J.P., Fliescher, S., Goeckner-Wald, N., Goldfinger, D.C., Grayson, J.A., Grimes, P., Hall, G., Halpern, M., Harrison, S.A., Henderson, S., Hildebrandt, S.R., Hilton, G.C., Hubmayr, J., Hui, H., Irwin, K.D., Kang, J., Karkare, K.S., Karpel, E., Kefeli, S., Kernasovskiy, S.A., Kovac, J.M., Kuo, C.L., LAU, K., Leitch, E.M., Megerian, K.G., Minutolo, L., Moncelsi, L., Nakato, Y., Namikawa, T.
• Other Authors: Institut Laue-Langevin (ILL), ILL, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), BICEP/Keck
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2020
• Subjects: Cosmic Microwave Background; Gravitational Waves; Inflation; BICEP; Keck Array; Polarization; cosmic background radiation: polarization; B-mode: primordial; gravitational radiation; B-mode; cosmic background radiation: temperature; numerical calculations; [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]; [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]; South Pole; South pole
• Online Access: https://hal.archives-ouvertes.fr/hal-03107940; https://doi.org/10.1117/12.2562729

International audience The Bicep/Keck Array experiment is a series of small-aperture refracting telescopes observing degree-scale Cosmic Microwave Background polarization from the South Pole in search of a primordial B-mode signature. As a pair differencing experiment, an important systematic that must be controlled is the differential beam response between the co-located, orthogonally polarized detectors. We use high-fidelity, in-situ measurements of the beam response to estimate the temperature-to-polarization (T → P) leakage in our latest data including observations from 2016 through 2018. This includes three years of Bicep3 observing at 95 GHz, and multifrequency data from Keck Array. Here we present band-averaged far-field beam maps, differential beam mismatch, and residual beam power (after filtering out the leading difference modes via deprojection) for these receivers. We show preliminary results of "beam map simulations," which use these beam maps to observe a simulated temperature (no Q/U) sky to estimate T → P leakage in our real data.