Title: Optimal strategy for polarization modulation in the LSPE-SWIPE experiment

Abstract

Context. Cosmic microwave background (CMB) B-mode experiments are required to control systematic effects with an unprecedented level of accuracy. Polarization modulation by a half wave plate (HWP) is a powerful technique able to mitigate a large number of the instrumental systematics. Aims. Our goal is to optimize the polarization modulation strategy of the upcoming LSPE-SWIPE balloon-borne experiment, devoted to the accurate measurement of CMB polarization at large angular scales. Methods. We departed from the nominal LSPE-SWIPE modulation strategy (HWP stepped every 60 s with a telescope scanning at around 12 deg/s) and performed a thorough investigation of a wide range of possible HWP schemes (either in stepped or continuously spinning mode and at different azimuth telescope scan-speeds) in the frequency, map and angular power spectrum domain. In addition, we probed the effect of high-pass and band-pass filters of the data stream and explored the HWP response in the minimal case of one detector for one operation day (critical for the single-detector calibration process). We finally tested the modulation performance against typical HWP-induced systematics. Results. Our analysis shows that some stepped HWP schemes, either slowly rotating or combined with slow telescope modulations, represent poor choices. Moreover, our results point out thatmore » the nominal configuration may not be the most convenient choice. While a large class of spinning designs provides comparable results in terms of pixel angle coverage, map-making residuals and BB power spectrum standard deviations with respect to the nominal strategy, we find that some specific configurations (e.g., a rapidly spinning HWP with a slow gondola modulation) allow a more efficient polarization recovery in more general real-case situations. Conclusions. Although our simulations are specific to the LSPE-SWIPE mission, the general outcomes of our analysis can be easily generalized to other CMB polarization experiments.« less

Authors:

Buzzelli, A.  ^[1];

• Search DOE PAGES for author "Buzzelli, A."
• Search DOE PAGES for ORCID "0000-0003-0832-415X"

de Bernardis, P. ^[1]; Masi, S.  ^[1];

• Search DOE PAGES for author "Masi, S."
• Search DOE PAGES for ORCID "0000-0001-5105-1439"

Vittorio, N. ^[1]; de Gasperis, G.  ^[1]

• Search DOE PAGES for author "de Gasperis, G."
• Search DOE PAGES for ORCID "0000-0003-2899-2171"

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+ Show Author Affiliations

1. Univ. di Roma (Italy). Dept. of Physics; National Inst. of Nuclear Physics (INFN), Rome (Italy)

Publication Date:

Fri Jan 05 00:00:00 EST 2018

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1495424

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Astronomy and Astrophysics

Additional Journal Information:

Journal Volume: 609; Journal Issue: Jan. 2018; Journal ID: ISSN 0004-6361

Publisher:

EDP Sciences

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS