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The OGLE Collection of Variable Stars. Over 450 000 Eclipsing and Ellipsoidal Binary Systems Toward the Galactic Bulge

Soszyński I., Pawlak M., Pietrukowicz P., Udalski A., Szymański M. K., Wyrzykowski Ł., Ulaczyk K., Poleski R., Kozłowski S., Skowron D. M., Skowron J., Mróz P., Hamanowicz A.

Acta Astronomica

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2016

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Vol. 66, No. 4

405--420

EN

We present a collection of 450 598 eclipsing and ellipsoidal binary systems detected in the OGLE fields toward the Galactic bulge. The collection consists of binary systems of all types: detached, semi-detached, and contact eclipsing binaries, RS CVn stars, cataclysmic variables, HW Vir binaries, double periodic variables, and even planetary transits. For all stars we provide the I- and V-band time-series photometry obtained during the OGLE-II, OGLE-III, and OGLE-IV surveys. We discuss methods used to identify binary systems in the OGLE data and present several objects of particular interest.

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The OGLE Collection of Variable Stars. Eclipsing Binaries in the Magellanic System

Pawlak M., Soszyński I., Udalski A., Szymański M. K., Wyrzykowski Ł., Ulaczyk K., Poleski R., Pietrukowicz P., Kozłowski S., Skowron D. M., Skowron J., Mróz P., Hamanowicz A.

Acta Astronomica

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2016

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Vol. 66, No. 4

421--432

EN

We present the collection of eclipsing binaries in the Large and Small Magellanic Clouds, based on the OGLE survey. It contains 48 605 systems, 40 204 belonging to the LMC and 8401 to the SMC. Out of the total number of presented here binaries, 16 374 are the new discoveries. We present the time-series photometry obtained for the selected objects during the fourth phase of the OGLE project. The catalog has been created using a two step machine learning procedure based on the Random Forest algorithm

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OGLE Study of the Sagittarius Dwarf Spheroidal Galaxy and its M54 Globular Cluster

Hamanowicz A., Pietrukowicz P., Udalski A., Mróz P., Soszyński I., Szymański M. K., Skowron J., Poleski R., Wyrzykowski Ł., Kozłowski S., Pawlak M., Ulaczyk K.

Acta Astronomica

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2016

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Vol. 66, No. 2

197--217

EN

We use the fundamental-mode RR Lyr-type variable stars (RRab) from OGLE-IV survey to draw a 3D picture of the central part of the tidally disrupted Sagittarius Dwarf Spheroidal (Sgr dSph) galaxy. We estimate the line-of-sight thickness of the Sgr dSph stream to be FWHMcen=2.42 kpc. Based on OGLE-IV observations collected in seasons 2011-2014 we conduct a comprehensive study of stellar variability in the field of the globular cluster M54 (NGC 6715) residing in the core of this dwarf galaxy. Among the total number of 268 detected variable stars we report the identification of 174 RR Lyr stars, four Type II Cepheids, 51 semi-regular variable red giants, three SX Phe-type stars, 18 eclipsing binary systems. Eighty-three variable stars are new discoveries. The distance to the cluster determined from RRab stars is dM54=26.7±0.03stat±1.3sys kpc. From the location of RRab stars in the period-amplitude (Bailey) diagram we confirm the presence of two old populations, both in the cluster and the Sgr dSph stream.