Over 10 000 Delta Scuti Stars toward the Galactic Bulge from OGLE-IV
  We present a collection of 10 111 genuine delta Sct-type pulsating variable
stars detected in the OGLE-IV Galactic bulge fields. In this sample, 9835
variables are new discoveries. For most of the stars photometric data cover the
whole decade 2010-2019. We illustrate a huge variety of light curve shapes of
delta Sct variables. Long-term observations have allowed us to spot objects
with evident period, amplitude, and mean brightness variations. Our analysis
indicates that about 28% of the stars are single-mode pulsators. Fourteen delta
Sct stars show additional eclipsing or ellipsoidal binary modulation. We report
significant attenuation or even disappearance of the pulsation signal in six
sources. The whole set of variables is a mix of objects representing various
Milky Way's populations, with the majority of stars from the Galactic bulge.
There are also representatives of the Sagittarius Dwarf Spheroidal Galaxy. Some
of the newly detected variables could be SX Phe-type stars residing in globular
clusters. The collection, including full V- and I-band time-series data, is
available to the astronomical community from the OGLE On-line Data Archive.
