  The discovery of 3:2 quasi-periodic oscillations (QPOs) in the ultraluminous
X-ray source NGC 1313 X-1 suggests it harbors an intermediate-mass black hole
(IMBH). We test this numerically by modelling the 3:2 QPOs and the associated
X-ray spectrum based on the epicyclic resonance model and a disk-corona model
with large-scale magnetic fields generated by the Cosmic Battery mechanism. The
combined QPO-frequency and spectral fitting indicates that the BH mass ranges
from 2524M_sun to 6811M_sun confirming its IMBH nature, and the BH spin is
probably higher than ~0.3.
