Numerical Simulations of the Circularized Accretion Flow in Population III Star Tidal Disruption Events. II. Radiative Properties

Abstract

Tidal Disruption Events (TDEs) release enormous amounts of energy, offering a promising avenue for detecting Population III (Pop III) stars. However, the radiative properties of TDEs of Pop III stars have so far been studied only analytically, relying on many assumptions. Based on our radiative hydrodynamic simulations that follow the evolution of the accretion system for Pop III star TDEs where a $300\ M_{\odot}$ ($M_{\odot}$ is the solar mass) star is disrupted by a $10^{6}\ M_{\odot}$ black hole (BH), we compute the emission properties of the event in rest frame and find that the spectrum peaks in the optical/UV waveband. After accounting for redshift ($z \sim 10$) and extinction effects, we find the observed spectral peak shifts to the infrared, with fluxes exceeding $10^{2}\mathrm{nJy}$-making such events detectable with both the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope (Roman). The dependence of the observed spectrum on viewing angle is suppressed due to dust extinction. Using our simulation results, we also calculate the radio emission generated by the interaction between the wind and the circumnuclear medium (CNM) and find that a Pop III star TDE can produce an unusually long-lasting, continuously increasing radio flare with a duration greater than $10^4$ days and thus has the potential to be detected in radio wavebands. These results may be helpful to the detection of Pop III stars.