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) approximate to 6.1 x 10(45) erg) or those at the X-ray band (W(e) approximate to 1.3 x 10(45) 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 pi(0) decay in proton-proton interaction. The energy required for iron nuclei released in the pulsar wind is W(Fe) approximate to 2.1 x 10(48) erg and the energy of iron nuclei transferred to positrons is W(e+) approximate to 8.4 x 10(45) erg in this case.