Postdoctoral Fellow, Johns Hopkins University
My research focuses on developing and applying machine learning methods for astrophysics and cosmology, spanning both Galactic archaeology and early-universe inference. At Johns Hopkins University, I currently work on spectral foundation models—such as SpecCLIP and its fine-tuned extensions—for cross-survey generalization across LAMOST, Gaia XP, DESI, Prime Focus Spectrograph (PFS), etc. I am also interested in the inference of dark matter profile from dwarf spheroidal galaxies with PFS. My previous doctoral research at Tsinghua University explored the epoch of reionization using simulation-based inference (SBI) and optimal summary statistics, and introduced generative approaches (e.g., diffusion models) for astrophysical image synthesis. Broadly, I am interested in connecting data-driven representation learning with physical interpretability to extract scientific insights from large, heterogeneous astronomical datasets.
Zhao, X., Ting, Y.-S., Szalay, A. S., Huang, Y., 2025, ICML ML4Astro Workshop
Lightweight adaptation approach for pre-trained spectral models, achieving few-shot generalization to DESI spectra.
Zhao, X., Huang, Y., Xue, G., Xiao Kong, et al., 2025 (submitted)
Foundation model for stellar spectra enabling cross-survey generalization between LAMOST LRS and Gaia XP.
Zhao, X., Ting, Y.-S., Diao, K., Mao, Y., 2023, Monthly Notices of the Royal Astronomical Society, 526, 1699
Applies denoising diffusion probabilistic models (DDPM) for conditional astrophysical image generation, bridging physical priors and deep generative modeling.
Zhao, X., Mao, Y., Cheng, C., Wandelt, B. D., 2022, Astrophysical Journal, 926, 151
Introduced a simulation-based inference framework that constrains reionization parameters directly from 3D 21 cm lightcone images.
Aug 2024 – Present | Baltimore, USA
Supervisors: Prof. Alex Szalay & Prof. Rosemary Wyse
Jul 2024 – Aug 2024 | Host: Prof. Yang Huang
Focus: stellar spectra foundation models.
2022 – 2024 | Mentor: Prof. Benjamin D. Wandelt
Focus: (explainable) ML for astrophysics and cosmology
2018 – 2024 | Advisor: Prof. Yi Mao
Thesis: Exploring the Epoch of Reionization with Machine Learning
2014 – 2018