New Galactic $\beta$ Lyrae-type Binaries Showing Superorbital
  Photometric Cycles
  We present the discovery of 32 new double periodic variables (DPVs) located
toward the Galactic bulge. We found these objects among the nearly half a
million binary stars published by the Optical Gravitational Lensing Experiment
project. With this discovery, we increase the number of known DPVs in the Milky
Way by a factor of 2. The new set of DPVs contains 31 eclipsing binaries and
one ellipsoidal variable star. The orbital periods cover the range from 1.6 to
26 days, while long periods are detected between 47 and 1144 days. Our analysis
confirms a known correlation between orbital and long periods that is also
observed in similar systems in the Magellanic Clouds.
