Recently , two of us have found a family of singularity-free rotating black hole solutions in Einstein ’ s conformal gravity .
These spacetimes are characterized by three parameters : the black hole mass M , the black hole spin angular momentum J , and a parameter L that is not specified by the theory but can be expected to be proportional to the black hole mass M .
The Kerr black hole solution of Einstein ’ s gravity is recovered for L = 0 .
In a previous paper , we showed that X-ray data of astrophysical black holes require L / M < 1.2 .
In the present paper , we report the results of a more sophisticated analysis .
We apply the X-ray reflection model relxill_nk to NuSTAR and Swift data of the supermassive black hole in 1H0707–495 .
We find the constraint L / M < 0.45 ( 90 % confidence level ) .