Light curve's recovery with Rubin-LSST: II. UnVEiling the darknesS of The gAlactic buLgE (VESTALE) with RR Lyrae

TL;DR

This study demonstrates that early Rubin-LSST observations can effectively recover RR Lyrae light curves in the Galactic bulge, enabling detailed analysis of the bulge's old stellar population and its formation history.

Contribution

It introduces simulations showing the potential of Rubin-LSST to study RR Lyrae stars in the Galactic bulge, accounting for reddening and crowding effects, supporting strategic observation planning.

Findings

Rubin-LSST can recover RR Lyrae light curves at the Galactic center.

Simulations highlight the impact of reddening and crowding on light curve analysis.

The study supports including the Bulge in LSST's main survey for galactic archaeology.

Abstract

This work is part of VESTALE, a project initiated within the Rubin-LSST Cadence Strategy Optimization Process . Its goal is to explore the potential of Rubin-LSST observations aimed at the Galaxy's bulge (Bulge) for studying RR Lyrae stars (RRL). Observation and analysis of RR Lyrae stars in the Bulge are crucial for tracing the old population of the central part of our galaxy and reconstructing the history of Bulge formation. Based on observations conducted with CTIO/DECam by Saha et al. 2019 towards the Baade Window, our simulations demonstrate that early Rubin-LSST observations will enable the recovery of RR Lyrae light curves at Galactic center distances with sufficient precision. This will allow us to utilize theoretical relations from Marconi et al. 2022 to determine their distances and/or metallicity, following the REDIME algorithm introduced in Bono et al. 2019. We show how reddening and crowding affect our simulations and highlight the importance of considering these effects when deriving pulsation parameters (luminosity amplitudes, mean magnitudes) based on the light curves especially if the goal is to explore the opposite side of the Bulge through the observation of its RRL. The simulations discussed in this investigation were conducted to support the SCOC's decision to observe this important sky region since it has only recently been decided to include part of the Bulge as a target within the LSST main survey.