The OGLE Collection of Variable Stars. One Thousand Heartbeat Stars in
  the Galactic Bulge and Magellanic Clouds
  We present a collection of 991 heartbeat star (HBS) candidates found in the
Optical Gravitational Lensing Experiment (OGLE) project data archive. We
discuss the selection process of the HBS candidates and the structure of the
catalog itself. It consists of 512 stars located toward the Galactic bulge
(GB), 439 stars located in the Large Magellanic Cloud (LMC), and 40 in the
Small Magellanic Cloud (SMC). The collection contains two large groups of HBSs
with different physical properties. The main distinction between the two groups
is the evolutionary status of the primary star. The first group of about 100
systems contains a hot main-sequence (MS) or a Hertzsprung-gap primary star,
while the second group of about 900 systems includes a red giant (RG). For each
star, we provide two-decade-long time-series photometry, in the Cousins $I$-
and Johnson $V$-band filters, obtained by the OGLE project. We also present
basic observational information as well as orbital parameters derived from the
light curve modeling.
