  We present the lightcurves, spectra, and hardness-intensity diagram (HID) of
the high mass X-ray binary V0332+53 using Fermi/GBM, MAXI, Swift/BAT, and
INTEGRAL through its 2015 Type II outburst. We observe characteristic features
in the X-ray emission (2-50 keV) due to periastron passages, the dynamical
timescale of the accretion disc, and changes within the accretion column
between a radiation-dominated flow and a flow dominated by Coulomb
interactions. Based on the HID and the light curves, the critical luminosity is
observed to decrease by ~5-7 percent during the outburst, signaling a decrease
in the magnetic field.
