Eclipse timing study of new hierarchical triple star candidates in the Northern Continuous Viewing Zone of TESS

We compiled a list of more than 3500 eclipsing binaries located in and near the Northern Continuous Viewing Zone (NCVZ) of the TESS space telescope that have a sufficient amount of TESS photometry to search for additional hidden components in these systems. We obtained the TESS light curves of all targets in an automated way applying convolution-aided differential photometry on the TESS Full-Frame Images from all available sectors up to Sector 60. Using a new self-developed Python GUI, we visually vetted all of these light curves, determined the eclipsing periods of the objects and calculated their eclipse timing variations (ETVs). The ETV curves were used in order to search for nonlinear variations that could be attributed to a light travel time effect (LTTE) or dynamical perturbations caused by additional components in these systems. We pre-selected 351 such candidates and tried to model their ETVs with the analytic formulae of pure LTTE or the combination of LTTE and dynamical perturbations. In total we could fit a model solution for the ETVs of 135 hierarchical triple candidates in which 10 systems were already known in the literature and the remainder of the 125 systems are new discoveries. Among these systems, there are some more noteworthy ones, such as five tight triples very close to their dynamical stability limit with a period ratio of less than 20 and three newly discovered triply eclipsing triples. We point out that dynamical perturbations are occurring in GZ Dra, which turns out to be a triple. We also made a comparison of the distributions of some orbital parameters coming from our solutions with those from the Kepler sample derived by Borkovits et al. (2016). Finally, we checked the correlations between the available parameters for systems that have Gaia Non-Single Star orbital solutions with those from our ETV solutions. (Abridged)