  Tidal disruption events are possible sources of temporary nuclear activity in
galactic nuclei and can be considered as good indicators of the existence of
super massive black holes in the centers of galaxies. A new X-ray source has
been serendipitously detected with ROSAT in a PSPC pointed observation of the
galaxy cluster A3571. Given the strong flux decay of the object in subsequent
detections, the tidal disruption scenario is investigated as possible
explanationof the event. We followed up the evolution of the X-ray transient
with ROSAT, XMM-Newton and Chandra for a total period of ~13 years. We also
obtained 7-band optical/NIR photometry with GROND at the ESO/MPI 2.2m
telescope. We report a very large decay of the X-ray flux of ROSAT source
identified with the galaxy LEDA 095953 a member of the cluster Abell 3571. We
measured a maximum 0.3-2.4 keV luminosity Log(L_X)=42.8 erg s^-1. The high
state of the source lasted at least 150 ks, afterwards L_X declined as ~t^-2.
The spectrum of the brightest epoch is consistent with a black body with
temperature kT ~0.12 keV. The total energy released by this event in 10 yr was
estimated to be Delta_E>2x10^50 erg. We interpret this event as a tidal
disruption of a solar type star by the central supermassive black hole (i.e.
~10^7 M_sun) of the galaxy.
