Enabling Cepheids and RR Lyrae science with Rubin/LSST

Florida State University, Tallahassee FL

Investigators

Abstract

A key question in astronomy is how the universe formed and changes with time. Recent observations show that stars and galaxies were born and grew quicker than expected. Other data suggest that the universe itself may be expanding faster than cosmological models predict. This program will help study these fundamental questions using the Vera Rubin telescope. The focus of this program is on Cepheids and RR Lyrae pulsating stars, which periodically change their brightness as their radius expands and contracts. The researchers will analyze the properties of these stars to understand the history of the galaxies where they are found. This program will pave the way for further studies of RR Lyrae and Cepheids with the Vera Rubin telescope. The scientific goals of this program are complemented by strong public outreach activities at the Florida State University planetarium. The main goals of this project are to enable Cepheids and RR Lyrae variables to serve as precision indicators of distance and metallicity for the Legacy Survey of Space and Time at the Rubin telescope (Rubin/LSST). The team will achieve this objective by combining new and archival Cepheids and RR Lyrae photometric time-series in key Rubin/LSST passbands with a large library of calibrating stars, derived from spectroscopic [Fe/H] abundances and accurate parallaxes measured by Gaia. With this dataset, they will: calibrate photometric metallicity relations to derive [Fe/H] abundances for hundreds of thousands of pulsating stars detected by Rubin/LSST; calibrate Period-Luminosity-Metallicity (PLZ) and Period-Wesenheit-Metallicity (PWZ) relations for Classical Cepheids and RR Lyrae in Rubin/LSST bands; and test these relations by studying the metallicity distribution of a sample of dwarf galaxies in the footprint of the Dark Energy Survey (DES) Wide-Area Survey. 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.