The mass of the central black hole in a galaxy that hosted a tidal disruption event ( TDE ) is an important parameter in understanding its energetics and dynamics .
We present the first homogeneously measured black hole masses of a complete sample of 12 optically/UV selected TDE host galaxies ( down to g _ { host } \leq 22 mag and z = 0.37 ) in the Northern sky .
The mass estimates are based on velocity dispersion measurements , performed on late time optical spectroscopic observations .
We find black hole masses in the range 3 \times 10 ^ { 5 } M _ { \odot } \leq M _ { BH } \leq 2 \times 10 ^ { 7 } M _ { \odot } .
The TDE host galaxy sample is dominated by low mass black holes ( \sim 10 ^ { 6 } M _ { \odot } ) , as expected from theoretical predictions .
The blackbody peak luminosity of TDEs with M _ { BH } \leq 10 ^ { 7.1 } M _ { \odot } is consistent with the Eddington limit of the SMBH , whereas the two TDEs with M _ { BH } \geq 10 ^ { 7.1 } M _ { \odot } have peak luminosities below their SMBH Eddington luminosity , in line with the theoretical expectation that the fallback rate for M _ { BH } \geq 10 ^ { 7.1 } M _ { \odot } is sub-Eddington .
In addition , our observations suggest that TDEs around lower mass black holes evolve faster .
These findings corroborate the standard TDE picture in 10 ^ { 6 } M _ { \odot } black holes .
Our results imply an increased tension between observational and theoretical TDE rates .
By comparing the blackbody emission radius with theoretical predictions , we conclude that the optical/UV emission is produced in a region consistent with the stream self-intersection radius of shallow encounters , ruling out a compact accretion disk as the direct origin of the blackbody radiation at peak brightness .