Speaker
Description
We aim to recover the SFH of the Milky Way disc, disentangling its chemically distinct components, by combining J-PLUS DR3 photometry
with Gaia astrometry. We fit magnitudes and parallaxes of 1.38 million dust-corrected stars using a Bayesian multiple-isochrone fitting technique. The bright region of the colour–absolute-magnitude diagramconstrains stellar ages, while the faint region provides an empirical metallicity prior that mitigates the age–metallicity degeneracy. We use PARSEC and BaSTI isochrones, adopting both solar-scaled and α-enhanced models.
The simultaneous fitting of solar-scaled and α-enhanced isochrones reveals distinct formation epochs for chemically different disc
populations: a rapid, well-mixed, α-enhanced phase between 12.5 and 8 Gyr ago, and a more extended, lower-intensity, solar-scaled phase from
∼ 9 to 3 Gyr ago. These findings demonstrate the capability of J-PLUS multi-filter photometry, in synergy with Gaia parallaxes, to mitigate
age–metallicity degeneracies and to disentangle patterns in the SFHs associated with the thin and thick discs. The methodology is readily applicable
to forthcoming wide-field, multi-filter surveys, enabling detailed mapping of the Milky Way's temporal and chemical evolution
