A unique large thermal source of real and virtual photons in the   reactions Pb(158 AGeV) + Pb, Au
  The data of direct single-photon measurements of the WA98 collaboration in the reaction Pb(158 AGeV) + Pb are analyzed within a thermal model with a minimum number of parameters adjusted to the dilepton data obtained by the CERES and NA50 collaborations in the reactions Pb(158 AGeV) + Au, Pb. The agreement of our model with the WA98 data points to a unique large thermal source emitting electromagnetic radiation observable in both the real and virtual photon channels. 
K. Gallmeister, B. Kampfer, O.P. Pavlenko