The Simons Observatory: impact of bandpass, polarization angle and calibration uncertainties on small-scale power spectrum analysis

Fuente: arXiv
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Main Authors: Giardiello, S., Gerbino, M., Pagano, L., Alonso, D., Beringue, B., Bolliet, B., Calabrese, E., Coppi, G., Errard, J., Fabbian, G., Harrison, I., Hill, J. C., Jense, H. T., Keating, B., La Posta, A., Lattanzi, M., Lonappan, A. I., Puglisi, G., Reichardt, C. L., Simon, S. M.
Format: Preprint
Published: 2024
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author Giardiello, S.
Gerbino, M.
Pagano, L.
Alonso, D.
Beringue, B.
Bolliet, B.
Calabrese, E.
Coppi, G.
Errard, J.
Fabbian, G.
Harrison, I.
Hill, J. C.
Jense, H. T.
Keating, B.
La Posta, A.
Lattanzi, M.
Lonappan, A. I.
Puglisi, G.
Reichardt, C. L.
Simon, S. M.
author_facet Giardiello, S.
Gerbino, M.
Pagano, L.
Alonso, D.
Beringue, B.
Bolliet, B.
Calabrese, E.
Coppi, G.
Errard, J.
Fabbian, G.
Harrison, I.
Hill, J. C.
Jense, H. T.
Keating, B.
La Posta, A.
Lattanzi, M.
Lonappan, A. I.
Puglisi, G.
Reichardt, C. L.
Simon, S. M.
contents We study the effects due to mismatches in passbands, polarization angles, and temperature and polarization calibrations in the context of the upcoming cosmic microwave background experiment Simons Observatory (SO). Using the SO multi-frequency likelihood, we estimate the bias and the degradation of constraining power in cosmological and astrophysical foreground parameters assuming different levels of knowledge of the instrumental effects. We find that incorrect but reasonable assumptions about the values of all the systematics examined here can have significant effects on cosmological analyses, hence requiring marginalization approaches at the likelihood level. When doing so, we find that the most relevant effect is due to bandpass shifts. When marginalizing over them, the posteriors of parameters describing astrophysical microwave foregrounds (such as radio point sources or dust) get degraded, while cosmological parameters constraints are not significantly affected. Marginalization over polarization angles with up to 0.25$^\circ$ uncertainty causes an irrelevant bias $\lesssim 0.05 σ$ in all parameters. Marginalization over calibration factors in polarization broadens the constraints on the effective number of relativistic degrees of freedom $N_\mathrm{eff}$ by a factor 1.2, interpreted here as a proxy parameter for non standard model physics targeted by high-resolution CMB measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2403_05242
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Simons Observatory: impact of bandpass, polarization angle and calibration uncertainties on small-scale power spectrum analysis
Giardiello, S.
Gerbino, M.
Pagano, L.
Alonso, D.
Beringue, B.
Bolliet, B.
Calabrese, E.
Coppi, G.
Errard, J.
Fabbian, G.
Harrison, I.
Hill, J. C.
Jense, H. T.
Keating, B.
La Posta, A.
Lattanzi, M.
Lonappan, A. I.
Puglisi, G.
Reichardt, C. L.
Simon, S. M.
Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
We study the effects due to mismatches in passbands, polarization angles, and temperature and polarization calibrations in the context of the upcoming cosmic microwave background experiment Simons Observatory (SO). Using the SO multi-frequency likelihood, we estimate the bias and the degradation of constraining power in cosmological and astrophysical foreground parameters assuming different levels of knowledge of the instrumental effects. We find that incorrect but reasonable assumptions about the values of all the systematics examined here can have significant effects on cosmological analyses, hence requiring marginalization approaches at the likelihood level. When doing so, we find that the most relevant effect is due to bandpass shifts. When marginalizing over them, the posteriors of parameters describing astrophysical microwave foregrounds (such as radio point sources or dust) get degraded, while cosmological parameters constraints are not significantly affected. Marginalization over polarization angles with up to 0.25$^\circ$ uncertainty causes an irrelevant bias $\lesssim 0.05 σ$ in all parameters. Marginalization over calibration factors in polarization broadens the constraints on the effective number of relativistic degrees of freedom $N_\mathrm{eff}$ by a factor 1.2, interpreted here as a proxy parameter for non standard model physics targeted by high-resolution CMB measurements.
title The Simons Observatory: impact of bandpass, polarization angle and calibration uncertainties on small-scale power spectrum analysis
topic Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2403.05242