  Aims: We present a study of the Be/X-ray binary system V 0332+53 with the
main goal of characterizing its behavior mainly during the
intermediate-luminosity X-ray event on 2008. In addition, we aim to contribute
to the understanding of the global behavior of the donor companion by including
optical data from our dedicated campaign starting on 2006. Methods: V 0332+53
was observed by RXTE and Swift during the decay of the intermediate-luminosity
X-ray outburst of 2008, as well as with Suzaku before the rising of the third
normal outburst of the 2010 series. In addition, we present recent data from
the Spanish ground-based astronomical observatories of El Teide (Tenerife),
Roque de los Muchachos (La Palma), and Sierra Nevada (Granada), and since 2006
from the Turkish TUBITAK National Observatory (Antalya). We have performed
temporal analyses to investigate the transient behaviour of this system during
several outbursts. Results: Our optical study revealed that continuous mass
ejection episodes from the Be star have been taking place since 2006 and
another one is currently ongoing. The broad-band 1-60 keV X-ray spectrum of the
neutron star during the decay of the 2008 outburst was well fitted with
standard phenomenological models, enhanced by an absorption feature of unknown
origin at about 10 keV and a narrow iron K-alpha fluorescence line at 6.4 keV.
For the first time in V 0332+53 we tentatively see an increase of the cyclotron
line energy with increasing flux (although further and more sensitive
observations are needed to confirm this). Regarding the fast aperiodic
variability, we detect a Quasi-Periodic Oscillation (QPO) at 227+-9 mHz only
during the lowest luminosities. The latter fact might indicate that the inner
regions surrounding the magnetosphere are more visible during the lowest flux
states.
