The ALMA Survey of Gas Evolution of PROtoplanetary discs (AGE-PRO): constraints on disc turbulence, fragmentation velocity, and inner pebble fluxes

ABSTRACT How substructures and disc properties affect dust evolution and the delivery of solids and volatiles into planet-forming regions remains an open question. We present results from tailored dust evolution modeling of the AGE–PRO ALMA large program, a sample of 30 protoplanetary discs spanning different evolutionary stages. Visibility fitting of the AGE–PRO ALMA data (at 1.3 mm) reveals that approximately half of the discs exhibit radial substructures. Combined with stellar properties, disc inclinations, and gas mass estimates from CO isotopologues and N$_2$H$^+$, this well-characterized set of discs provides an ideal testbed to constrain dust evolution models across different ages and disc morphologies. Using the dust evolution code dustpy, we simulate dust evolution in each disc under four model configurations, varying two key free parameters: the turbulent viscosity ($\alpha = 10^{-4}, 10^{-3}$) and fragmentation velocity ($v_{\rm {frag}} = 1 \mathrm{m\, s^{-1}}, 10 \mathrm{m\, s^{-1}}$). Pressure traps are incorporated by perturbing the gas surface density based on the continuum intensity profiles, and synthetic observations generated with radmc-3d are compared to these profiles. While no single model fits all discs, nearly half are best reproduced by the configuration with low turbulence and low fragmentation velocity ($\alpha = 10^{-4}, v_{\rm {frag}} = 1\, \mathrm{m\, s^{-1}}$). Models of smooth discs underpredict dust mass, possibly indicating unresolved substructures. Pebble fluxes into inner disc regions correlate more strongly with disc age than with the presence of substructures, highlighting time-dependent dust transport as a key factor in shaping inner disc composition. Our results also provide a comparative baseline for interpreting multiwavelength and James Webb Space Telescope (JWST) water vapor observations.