  Detailed study of centrality dependence of low-p_t manifestation of so-called
"near-side ridge" phenomenon is reported recently by STAR for all charged
hadrons with p_t>0.15 GeV/c from AuAu collisions at 62 and 200 GeV at RHIC[1].
It is indicating the existence of the energy-dependent centrality point where
some sudden changes in the correlation pattern are observed. In the present
work we use the hypothesis of string percolation phase transition for the
description of the onset of this ridge. One may assume that the formation of
rather large "macroscopic" clusters composed of several overlapped strings
extended in rapidity and localized in azimuth could be one of the possible
processes leading to the observed phenomenon.
  This onset is characterized by some definite ("critical") number of
participating nucleons. We use also another physical quantity, transverse
particle density, to characterize this threshold behavior, this variable brings
the transition points for two energies to coincidence [1]. So parameters of the
percolation model are defined at these critical points. Also we use results of
our previous calculations[2] for energy of collision 17.3 GeV based on observed
threshold of anomalous suppression of J/psi. Obtained parameters are
extrapolated to AA and pp collisions for energies over the range 17.3 GeV -
7000 GeV.
