  The PHOBOS experiment at RHIC has the unique capability of measuring particle
production at very low transverse momenta. New results on low-transverse
momentum invariant yields of pions, kaons, protons and antiprotons in 200 GeV
Au+Au collisions are presented as a function of the collision centrality for
the 50% most central events. In contrast to the results from d+Au collisions,
no $m_{T}$ scaling is observed in the very low $p_{T}$ region. The low
transverse momentum yields agree with extrapolations from intermediate
transverse momentum measurements. For all collision centralities a flattening
of the transverse momentum spectra is observed, consistent with a rapid
transverse expansion of the system.
