Better Characterizing the Time-Varying Microwave Environment on Cerro Toco

Surveys of the cosmic microwave background seek to answer outstanding questions in cosmology and particle physics. This includes investigating the nature of inflation and the properties of neutrinos. Upcoming instruments will create precise maps of the sky in temperature and polarization across a broad range of microwave frequencies.

However, these increasingly sensitive instruments are vulnerable to interference from nearby sources of microwave emission. Developing better tools to monitor the microwave environment now will help in planning for the next generation of such surveys. This will help in maximizing the scientific output of these surveys.

The principal investigator will also incorporate aspects of this work into course-based undergraduate research. These research experiences will reach a broad audience at the University of New Mexico.

This work will develop small-scale instrumentation and analysis tools for better monitoring of the time-varying microwave environment on and above Cerro Toco, at the site of the current POLARBEAR/Simons Array CMB experiment. These tools and datasets will help better understand and possibly increase the achievable sensitivity and survey area for upcoming ultra-wide survey cosmic microwave background polarization measurements that will be made from the same site by Simons Observatory and CMB-S4.

This work includes using low-level data from the current POLARBEAR/Simons Array instruments to characterize the atmosphere in detail, including the occurrence of tropospheric ice clouds that were observed by POLARBEAR-1 to create polarized microwave radiation. This unique dataset would be enhanced and used to understand indicators of conditions going forwards by the development of small-scale instrumentation for monitoring, measuring, and predicting the microclimate and microwave environment on Cerro Toco.

This project is jointly funded by the ATI program of the Division of Astronomical Sciences and by the Established Program to Stimulate Competitive Research (EPSCoR).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.