Figure 6

Direct photon spectra in Pb-Pb collisions at $\snn$=2.76 TeV and $\snn$=0.2 TeV, in both cases for the 0-20% centrality class. The spectra in both cases are the measured direct photon spectra, i.e., the contribution of pQCD photons was not subtracted. In case of the ALICE data, the slope of the exponential shown in the figure was determined without the subtraction of a pQCD contribution, while in the PHENIX case, the slope was determined after subtracting a pQCD contribution. In PHENIX, the pQCD contribution was determined by parameterizing a direct photon measurement in pp collisions