  The Be/X-ray binary 1A 0535+262 underwent a giant X-ray outburst in November
2020, peaking at $\sim1\times 10^{38}$ erg s$^{-1}$ (1--100 keV, 1.8 kpc), the
brightest outburst recorded for this source so far. Our goal is to search for
patterns of correlated spectral and timing behavior that can be used to
characterize the accretion states in hard X-ray transient pulsars. We have
studied the evolution of the spectral continuum emission using
hardness-intensity diagrams and the aperiodic variability of the source. The
hardness-intensity diagram displays three distinct branches that can be
identified with different accretion regimes. The characteristic frequency of
the noise components correlates with the luminosity. Our observations cover the
highest end of this correlation, at luminosities not previously sampled. We
have found evidence for a flattening of the correlation at those high
luminosities, which might indicate that the accretion disk reached the closest
distance from the neutron star surface during the peak of the outburst. We also
find evidence for hysteresis in the spectral and timing parameters: at the same
luminosity level, the spectrum is harder and the characteristic noise frequency
larger during the rise than during the decay of the outburst.

High Energy Astrophysical Phenomena