  We model the light curves of the novel and extremely luminous transient
ASASSN-15lh at nine different frequencies, from infrared to ultra-violet photon
energies, as an evolving relativistic disc produced in the aftermath of a tidal
disruption event. Good fits to all nine light curves are simultaneously
obtained when $M_{\rm acc} \simeq 0.07 M_{\odot}$ is accreted onto a black hole
of mass $M \simeq 10^9 M_{\odot}$, and near maximal rotation $a/r_g = 0.99$.
The best fit black hole mass is consistent with a number of existing estimates
from galactic scaling relationships. If confirmed, our results represent the
detection of one of the most massive rapidly spinning black holes to date, and
are strong evidence for a TDE origin for ASASSN-15lh. This would be the first
TDE to be observed in the disc dominated state at optical and infrared
frequencies.
