The observation of a population of massive black hole binaries (MBHBs) is key
for our complete understanding of galaxy mergers and for the characterization
of the expected gravitational waves (GWs) signal. However, MBHBs still remain
elusive with only a few candidates proposed to date. Among these,
SDSSJ143016.05+230344.4 (‘tick-tock’ hereafter) is the only candidate with a
remarkably well sampled light curve showing a clear reduction of the modulation
period and amplitude over three years of observations. This particular feature
has been recently claimed to be the signature of a MBHB that is about to merge.
In this paper, we provide an optical follow-up of the tick-tock source using
the Rapid Eye Mount (REM) telescope. The decreasing luminosity observed in our
follow up is hardly explained within the binary scenario. We speculate about an
alternative scenario that might explain the observed light curve through
relativistic Lense-Thirring precession of an accretion disc around a single
massive black hole.
