Hard TeV Gamma-Ray Afterglows of Nearby GRB 190829A as a Tentative Signature of Ultra-high-energy Cosmic Rays Accelerated in Gamma-Ray Burst Jets

The observed hard TeV gamma-ray spectrum of the nearby burst (GRB) 190829A may challenge conventional leptonic GRB afterglow model. It has been proposed that an ultra-high-energy (UHE; $\varepsilon^{'}_{\rm p}\sim 10^{20}$ eV) proton population can be pre-accelerated by internal shocks in jets. We study possible signatures UHE protons embedded afterglows when they escape fireball. show model represent multiwavelength lightcurves and spectral energy distributions considering uncertainties parameters. Attributing to emission both electron self-Compton scattering process synchrotron radiations fireball, we obtain tentative upper limits $\log_{10} \varepsilon_{\rm p}^{\prime}/{\rm eV}\sim 20.46$ $\log_{10}E_{\rm p, total}/{\rm erg}\leq 50.75$, where $E_{\rm total}$ is total population. should dominate early afterglows, implying observations are critical for revealing