Precipitable Water Vapor, Temperature, and Wind Statistics At Sites Suitable for mm and Submm Wavelength Astronomy in Northern Chile

TL;DR

This study provides statistical data on precipitable water vapor, temperature, and wind at potential astronomical sites in Northern Chile, aiding the planning of future mm/submm radio telescopes like ALMA and AtLAST.

Contribution

It offers comprehensive environmental statistics crucial for selecting optimal sites for mm/submm radio astronomy in Northern Chile.

Findings

PWV levels indicate extremely dry conditions suitable for mm/submm observations.

Temperature and wind data highlight environmental stability and challenges for telescope operation.

Results support site selection for future large-aperture radio telescopes.

Abstract

Atmospheric water vapor is the main limiting factor of atmospheric transparency in the mm and submm wavelength spectral windows. Thus, dry sites are needed for the installation and successful operation of radio astronomy observatories exploiting those spectral windows. Temperature and wind are variables of special consideration when planning the installation and operation of large-aperture radio telescopes, as these parameters affect the mechanical response of radio telescopes exposed to the environmental conditions. Temperature, and in particular temperature gradients, induce thermal deformation of mechanical structures, while high wind speeds and gusts induce pointing jitter affecting the tracking accuracy of astronomical sources during the observations. This work summarizes the statistics of precipitable water vapor (PWV), temperature, and wind monitored at sites by the coastal mountain range, as well as on the west slope of the Andes mountain range in the region of Antofagasta, Chile. This information could prove useful for the planning of extended baselines for the Atacama Large Millimeter and Submillimeter Array (ALMA), and/or new radio telescope projects, such as the Atacama Large Aperture Submm/ mm Telescope (AtLAST) initiative.