TeV Gamma-Ray Emission from Vela X: Leptonic or Hadronic?

We study nonthermal photon emission properties from Vela X in both a leptonic and a hadronic-leptonic model. In the leptonic model, it is difficult to reproduce the observed photon spectrum from X-ray to TeV bands using reasonable model parameters; the model results can compare with either the observed data at the TeV band (the total energy of electrons required to match the observations is W e 6.1 X 1045 erg) or those at the X-ray band (W e 1.3 X 1045 erg). In the hadronic-leptonic model, however, the observed photon spectrum can be reproduced in the hadronic-leptonic model and TeV photons are mainly from Delta *p0 decay in proton-proton interaction. The energy required for iron nuclei released in the pulsar wind is W Fe 2.1 X 1048 erg and the energy of iron nuclei transferred to positrons is erg in this case.