J-ATLAS: Javalambre Andromeda and Triangulum Legacy Astrophysical Survey
arXiv:2607.27052
J-ATLAS is a proposed wide-field optical photospectroscopic survey of the Andromeda (M31) and Triangulum (M33) galaxies that will obtain low‑resolution spectral energy distributions for stars and other objects to study the structure and stellar content of galaxy outskirts.
Abstract
The outskirts of nearby galaxies preserve long-lived signatures of hierarchical assembly and provide a fossil record of galaxy formation. J-ATLAS, the Javalambre Andromeda and Triangulum Legacy Astrophysical Survey, is a proposed wide-field optical photospectroscopic survey of the M31--M33 system with JST/T250 and JPCam. Using the dense J-PAS filter system, it will deliver homogeneous low-resolution optical SEDs for resolved stars, compact stellar systems, emission-line sources, and background objects across the nearest massive spiral-galaxy environment visible from the northern sky. The survey will map disks, halos, streams, satellites, and the intergalactic region, constraining stellar populations, photometric metallicities, carbon-rich evolved stars, star clusters, planetary nebulae, and low-surface-brightness substructure. We also present the ongoing pilot survey, centred on the Giant Southern Stream and Andromeda~I, whose 92 complete pointings are being analysed to validate crowded-field photometry, calibration, source classification, and photometric metallicity diagnostics before extending the methodology to the full J-ATLAS footprint survey.
The Hidden Beauty of the Galactic Outskirts. Proceeding IAU Symposium 403, 2025