Speaker
Description
Individual stars located near the caustics of galaxy clusters can undergo extreme magnification when crossing micro-caustics, making them observable even at cosmological distances. Although most massive stars are likely to reside in binary systems rather than as single stars, the influence of binary star systems on magnification events remains severely underexplored. In this report, I will present our recent work on simulating the light curves of detached binary stars crossing micro-caustics to characterize their unique observational signatures. High-resolution magnification maps, generated using the GPU-PMO-CAUSTIC algorithm, combined with PARSEC stellar models to construct redshifted binary star systems, allow us to investigate the impact of binary star parameters and crossing geometries on microlensing magnification patterns.
Our simulations reveal diverse light curve features, including overlapping peaks, plateau-like structures, and time-variable color-magnitude differences. Notably, the distinct temporal variations in spectral energy distributions provide diagnostic tools for distinguishing binary systems from single stars, particularly highlighting the potential of multi-band photometry with the Chinese Space Station Telescope’s Multi-Channel Imager (CSST-MCI) to capture these variations. These findings offer theoretical support for identifying binary systems in future caustic-crossing events, contributing to a more precise characterization of high-redshift stellar populations.
