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author Hervías-Caimapo, Carlos
Wolz, Kevin
La Posta, Adrien
Azzoni, Susanna
Alonso, David
Arnold, Kam
Baccigalupi, Carlo
Biquard, Simon
Brown, Michael L.
Calabrese, Erminia
Chinone, Yuji
Day-Weiss, Samuel
Dunkley, Jo
Dünner, Rolando
Errard, Josquin
Fabbian, Giulio
Ganga, Ken
Giardiello, Serena
Hertig, Emilie
Huffenberger, Kevin M.
Johnson, Bradley R.
Jost, Baptiste
Keskitalo, Reijo
Kisner, Theodore S.
Louis, Thibaut
Morshed, Magdy
Page, Lyman A.
Reichardt, Christian L.
Rosenberg, Erik
Silva-Feaver, Max
Sohn, Wuhyun
Sueno, Yoshinori
Thomas, Dan B.
Sang, Ema Tsang King
Villarrubia-Aguilar, Amalia
Yamada, Kyohei
author_facet Hervías-Caimapo, Carlos
Wolz, Kevin
La Posta, Adrien
Azzoni, Susanna
Alonso, David
Arnold, Kam
Baccigalupi, Carlo
Biquard, Simon
Brown, Michael L.
Calabrese, Erminia
Chinone, Yuji
Day-Weiss, Samuel
Dunkley, Jo
Dünner, Rolando
Errard, Josquin
Fabbian, Giulio
Ganga, Ken
Giardiello, Serena
Hertig, Emilie
Huffenberger, Kevin M.
Johnson, Bradley R.
Jost, Baptiste
Keskitalo, Reijo
Kisner, Theodore S.
Louis, Thibaut
Morshed, Magdy
Page, Lyman A.
Reichardt, Christian L.
Rosenberg, Erik
Silva-Feaver, Max
Sohn, Wuhyun
Sueno, Yoshinori
Thomas, Dan B.
Sang, Ema Tsang King
Villarrubia-Aguilar, Amalia
Yamada, Kyohei
contents We present a transfer function-based method to estimate angular power spectra from filtered maps for cosmic microwave background (CMB) surveys. This is especially relevant for experiments targeting the faint primordial gravitational wave signatures in CMB polarisation at large scales, such as the Simons Observatory (SO) small aperture telescopes. While timestreams can be filtered to mitigate the contamination from low-frequency noise, usual methods that calculate the mode coupling at individual multipoles can be challenging for experiments covering large sky areas or reaching few-arcminute resolution. The method we present here, although approximate, is more practical and faster for larger data volumes. We validate it through the use of simulated observations approximating the first year of SO data, going from half-wave plate-modulated timestreams to maps, and using simulations to estimate the mixing of polarisation modes induced by an example of time-domain filtering. We show its performance through an example null test and with an end-to-end pipeline that performs inference on cosmological parameters, including the tensor-to-scalar ratio $r$. The performance demonstration uses simulated observations at multiple frequency bands. We find that the method can recover unbiased parameters for our simulated noise levels.
format Preprint
id arxiv_https___arxiv_org_abs_2502_00946
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Simons Observatory: Validation of reconstructed power spectra from simulated filtered maps for the Small Aperture Telescope survey
Hervías-Caimapo, Carlos
Wolz, Kevin
La Posta, Adrien
Azzoni, Susanna
Alonso, David
Arnold, Kam
Baccigalupi, Carlo
Biquard, Simon
Brown, Michael L.
Calabrese, Erminia
Chinone, Yuji
Day-Weiss, Samuel
Dunkley, Jo
Dünner, Rolando
Errard, Josquin
Fabbian, Giulio
Ganga, Ken
Giardiello, Serena
Hertig, Emilie
Huffenberger, Kevin M.
Johnson, Bradley R.
Jost, Baptiste
Keskitalo, Reijo
Kisner, Theodore S.
Louis, Thibaut
Morshed, Magdy
Page, Lyman A.
Reichardt, Christian L.
Rosenberg, Erik
Silva-Feaver, Max
Sohn, Wuhyun
Sueno, Yoshinori
Thomas, Dan B.
Sang, Ema Tsang King
Villarrubia-Aguilar, Amalia
Yamada, Kyohei
Cosmology and Nongalactic Astrophysics
We present a transfer function-based method to estimate angular power spectra from filtered maps for cosmic microwave background (CMB) surveys. This is especially relevant for experiments targeting the faint primordial gravitational wave signatures in CMB polarisation at large scales, such as the Simons Observatory (SO) small aperture telescopes. While timestreams can be filtered to mitigate the contamination from low-frequency noise, usual methods that calculate the mode coupling at individual multipoles can be challenging for experiments covering large sky areas or reaching few-arcminute resolution. The method we present here, although approximate, is more practical and faster for larger data volumes. We validate it through the use of simulated observations approximating the first year of SO data, going from half-wave plate-modulated timestreams to maps, and using simulations to estimate the mixing of polarisation modes induced by an example of time-domain filtering. We show its performance through an example null test and with an end-to-end pipeline that performs inference on cosmological parameters, including the tensor-to-scalar ratio $r$. The performance demonstration uses simulated observations at multiple frequency bands. We find that the method can recover unbiased parameters for our simulated noise levels.
title The Simons Observatory: Validation of reconstructed power spectra from simulated filtered maps for the Small Aperture Telescope survey
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2502.00946