Detecting Population III Stars through Tidal Disruption Events with the GREX-PLUS Telescope

This project investigated the potential for detecting Population III stars through tidal disruption events (TDEs) using the GREX-PLUS telescope, a mission concept considered by the Japan Aerospace Exploration Agency (JAXA). A TDE occur when a star passes close to a supermassive black hole and is torn apart by it's tidal forces, producing a bright flare that can be observed in multiple wavelengths. We investigated how different factors, such as black hole mass, stellar mass, redshift, and the metallicity of the star, affected the observed flux and the probability of detecting a TDE with GREX-PLUS. By studying the spectral energy distribution (SED) and observable fluxes emitted by TDEs, we found that radiation changed with these factors and impacted the detection rate. We discovered that the mass of the black hole had the biggest impact on the detection probability, with higher masses leading to higher flux, making detection easier, even at higher redshifts. Stellar mass and metallicity also affected the detection rate, with lower stellar mass and higher metallicity giving a low probability to detect TDEs. We also compared GREX-PLUS with the Roman Space Telescope and the NIRCam instrument on the James Webb Space Telescope (JWST) and found that GREX-PLUS is better at detecting the peak flux of a TDE, which is essential for distinguishing and categorizing TDEs. Roman Space Telescope is not capable of detecting most TDE fluxes and only observes the later stages of extreme TDE cases. While JWST can detect fluxes for a range of black hole and stellar masses, it cannot capture the peak flux, making GREX-PLUS more effective for studying TDEs.