Eclipse timing variation analysis of OGLE-IV eclipsing binaries toward the Galactic Bulge. II. Short periodic triple stellar systems.

We report an eclipse timing variations (ETV) study to identify close, stellar mass companions to the eclipsing binaries monitored during the photometric survey OGLE-IV. We also present an alternative automatic way to determine the first and last contacts of an eclipse. Applying the phase dispersion minimization method to identify potential triples, we find close third components with outer periods less than 1500 days in 23 systems. We present outer orbit solution for 21 of 23 systems. For the ten, tightest triples we find that the ETV can only be modeled with the combination of the light-travel time effect (LTTE) and third-body perturbations, while in case of another 11 systems, pure LTTE solutions are found to be satisfactory. In the remaining two systems we identify extra eclipses connected to the outer component, but for the incomplete and noisy ETV curves, we are unable to find realistic three-body solutions. Therefore, in these cases we give only the outer period.