We present results from a systematic selection of tidal disruption events ( TDEs ) in a wide-area ( 4800 deg ^ { 2 } ) , g + R band , Intermediate Palomar Transient Factory ( iPTF ) experiment .
Our selection targets typical optically-selected TDEs : bright ( > 60 % flux increase ) and blue transients residing in the center of red galaxies .
Using photometric selection criteria to down-select from a total of 493 nuclear transients to a sample of 26 sources , we then use follow-up UV imaging with the Neil Gehrels Swift Telescope , ground-based optical spectroscopy , and light curve fitting to classify them as 14 Type Ia supernovae ( SNe Ia ) , 9 highly variable active galactic nuclei ( AGNs ) , 2 confirmed TDEs , and 1 potential core-collapse supernova .
We find it possible to filter AGNs by employing a more stringent transient color cut ( g - r < - 0.2 mag ) ; further , UV imaging is the best discriminator for filtering SNe , since SNe Ia can appear as blue , optically , as TDEs in their early phases .
However , when UV-optical color is unavailable , higher precision astrometry can also effectively reduce SNe contamination in the optical .
Our most stringent optical photometric selection criteria yields a 4.5:1 contamination rate , allowing for a manageable number of TDE candidates for complete spectroscopic follow-up and real-time classification in the ZTF era .
We measure a TDE per galaxy rate of 1.7 ^ { +2.9 } _ { -1.3 } \times 10 ^ { -4 } gal ^ { -1 } yr ^ { -1 } ( 90 % CL in Poisson statistics ) .
This does not account for TDEs outside our selection criteria , thus may not reflect the total TDE population , which is yet to be fully mapped .