Title:	The Simons Observatory: Galactic Science Goals and Forecasts
Authors:	Hensley, Brandon S. Fanfani, Valentina Krachmalnicoff, Nicoletta Fabbian, Giulio Poletti, Davide Puglisi, Giuseppe Coppi, Gabriele Nibauer, Jacob Gerasimov, Roman Galitzki, Nicholas Choi, Steve K. Ashton, Peter C. Baccigalupi, Carlo Baxter, Eric Burkhart, Blakesley Calabrese, Erminia Chluba, Jens Errard, Josquin Frolov, Andrei V. Hervías-Caimapo, Carlos Huffenberger, Kevin M. Johnson, Bradley R. Jost, Baptiste Keating, Brian McCarrick, Heather Nati, Federico Sathyanarayana Rao, Mayuri Engelen, Alexander van Walker, Samantha Wolz, Kevin Xu, Zhilei Zhu, Ningfeng Zonca, Andrea Clark, Susan E.
Keywords:	Interstellar medium Interstellar magnetic fields Interstellar molecules Interstellar dust Polarimetry Interstellar synchrotron emission Oort cloud objects Cosmic microwave background radiation Magnetohydrodynamics Starlight polarization
Issue Date:	26-Apr-2022
Publisher:	The American Astronomical Society
Citation:	The Astrophysical Journal, 2022, Vol.929, p166
Abstract:	Observing in six frequency bands from 27 to 280 GHz over a large sky area, the Simons Observatory (SO) is poised to address many questions in Galactic astrophysics in addition to its principal cosmological goals. In this work, we provide quantitative forecasts on astrophysical parameters of interest for a range of Galactic science cases. We find that SO can: constrain the frequency spectrum of polarized dust emission at a level of Δβd ≲ 0.01 and thus test models of dust composition that predict that βd in polarization differs from that measured in total intensity; measure the correlation coefficient between polarized dust and synchrotron emission with a factor of two greater precision than current constraints; exclude the nonexistence of exo-Oort clouds at roughly 2.9σ if the true fraction is similar to the detection rate of giant planets; map more than 850 molecular clouds with at least 50 independent polarization measurements at 1 pc resolution; detect or place upper limits on the polarization fractions of CO(2–1) emission and anomalous microwave emission at the 0.1% level in select regions; and measure the correlation coefficient between optical starlight polarization and microwave polarized dust emission in 1° patches for all lines of sight with NH ≳ 2 × 1020 cm−2. The goals and forecasts outlined here provide a roadmap for other microwave polarization experiments to expand their scientific scope via Milky Way astrophysics.
Description:	Open Access
URI:	http://hdl.handle.net/2289/7948
ISSN:	0004-637X 1538-4357(Online)
Alternative Location:	https://ui.adsabs.harvard.edu/abs/2022ApJ...929..166H/abstract https://arxiv.org/abs/2111.02425 https://doi.org/10.3847/1538-4357/ac5e36
Copyright:	2022 The Author(s)
Appears in Collections:	Research Papers (A&A)

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