High Amplitude \delta-Scutis in the Large Magellanic Cloud

TL;DR

This study reports the discovery of 2323 high-amplitude delta-Scuti candidates in the Large Magellanic Cloud, analyzing their pulsation modes, period-luminosity relations, and identifying a subluminous population.

Contribution

It provides the first large-scale catalog of HADS in the LMC and analyzes their pulsation modes and period-luminosity relations, revealing new insights into their properties.

Findings

Several HADS are multimode pulsators.

FO and F mode PL relations overlap, unlike other pulsators.

Evidence for a subluminous, high-amplitude HADS population.

Abstract

We present 2323 High-Amplitude \delta-Scuti (HADS) candidates discovered in the Large Magellanic Cloud (LMC) by the SuperMACHO survey (Rest et al. 2005). Frequency analyses of these candidates reveal that several are multimode pulsators, including 119 whose largest amplitude of pulsation is in the fundamental (F) mode and 19 whose largest amplitude of pulsation is in the first overtone (FO) mode. Using Fourier decomposition of the HADS light curves, we find that the period-luminosity (PL) relation defined by the FO pulsators does not show a clear separation from the PL-relation defined by the F pulsators. This differs from other instability strip pulsators such as type c RR Lyrae. We also present evidence for a larger amplitude, subluminous population of HADS similar to that observed in Fornax (Poretti et al. 2008).