Hadronic Models for the Extra Spectral Component in the short GRB 090510

A short gamma-ray burst GRB 090510 detected by {\it Fermi} shows an extra spectral component between 10 MeV and 30 GeV, an addition to a more usual low-energy ($<10$ MeV) Band component. In general, such an extra component could originate from accelerated protons. In particular, inverse Compton emission from secondary electron-positron pairs and proton synchrotron emission are competitive models for reproducing the hard spectrum of the extra component in GRB 090510. Here, using Monte Carlo simulations, we test the hadronic scenarios against the observed properties. To reproduce the extra component around GeV with these models, the proton injection isotropic-equivalent luminosity is required to be larger than $10^{55}$ erg$ / $s. Such large proton luminosities are a challenge for the hadronic models.