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The OGLE Collection of Variable Stars

Over 15,000 δ Scuti Stars in the Large Magellanic Cloud

I. Soszyński, P. Pietrukowicz, A. Udalski, J. Skowron, M. K. Szymański, R. Poleski, D. M. Skowron, S. Kozłowski, P. Mróz, P. Iwanek, M. Wrona, K. Ulaczyk, K. Rybicki, M. Gromadzki, and M. Mróz
Acta Astronomica, 73, 105 (arXiv:2309.15147)
Data download: OCVS/LMC/DSCT

We present the OGLE collection of δ Scuti stars in the Large Magellanic Cloud and in its foreground. Our dataset encompasses a total of 15,256 objects, constituting the largest sample of extragalactic δ Sct stars published so far. In the case of 12 δ Sct pulsators, we detected additional eclipsing or ellipsoidal variations in their light curves. These are the first known candidates for binary systems containing δ Sct components beyond the Milky Way. We provide observational parameters for all variables, including pulsation periods, mean magnitudes, amplitudes, and Fourier coefficients, as well as long-term light curves in the I- and V-bands collected during the fourth phase of the OGLE project.

Disentangled I-band light curves of delta Sct stars showing additional eclipsing or ellipsoidal modulation

We construct the period-luminosity (PL) diagram, in which fundamental-mode and first-overtone δ Sct stars form two nearly parallel ridges. The latter ridge is an extension of the PL relation obeyed by first-overtone classical Cepheids. The slopes of the PL relations for δ Sct variables are steeper than those for classical Cepheids, indicating that the continuous PL relation for first-overtone δ Sct variables and Cepheids is non-linear, exhibiting a break at a period of approximately 0.5 d.

Period-luminosity diagram for delta Sct stars in the LMC

We also report the enhancement of the OGLE collection of Cepheids and RR Lyrae stars with newly identified and reclassified objects, including pulsators contained in the recently published Gaia DR3 catalog of variable stars. As a by-product, we estimate the contamination rate in the Gaia DR3 catalogs of Cepheids and RR Lyrae variables.

On-sky map of delta Sct stars in the LMC

OGLE photometric data are available to the astronomical community from the OGLE Internet Archive and through the on-line search form in the OGLE Collection of Variable Stars.

PLEASE cite the following paper when using the data or referring to these OGLE results:
Soszyński et al., 2023, Acta Astronomica, 73, 105, (arXiv:2309.15147)

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