Empirical derivation of the metallicity evolution with time and radius using TNG50 Milky Way/Andromeda analogues

Recent works have used a linear birth metallicity gradient to estimate the evolution of the [Fe/H] profile in the Galactic disk over time, and infer stellar birth radii (R${}_{\text{birth}}$) from [Fe/H] and age measurements. These estimates rely on the evolution of [Fe/H] at the Galactic center ([Fe/H](0, $\tau$)) and the birth metallicity gradient ($\mathrm{\nabla }$Fe/H$)overtime--quantitiesthatareunknownandinferredunderkeyassumptions\mathrm{.}Inthiswork,weusethesampleofMilkyWay\mathrm{/}AndromedaanaloguesfromtheTNG50simulationtoinvestigatetheabilitytorecover[Fe\mathrm{/}H](R,$τ$)andR$$\text{birth}$$inavarietyofgalaxies\mathrm{.}Usingstellardiskparticles,wetesttheassumptionsrequiredinestimatingR$$\text{birth}$$,[Fe\mathrm{/}H](0,$τ$),and$\nabla$[Fe\mathrm{/}H]($τ)$usingrecentlyproposedmethodstounderstandwhentheyarevalid\mathrm{.}Weshowthat$\nabla$[Fe\mathrm{/}H]($τ)$canberecoveredinmostgalaxiestowithin26$τ$)canbeconstrainedandconfirmedbyrequiringtheR$$\text{birth}$$distributionsofmono-age,solarneighborhoodpopulationstofollowinside-outformation\mathrm{.}WeconcludethatexaminingtrendswithR$$\text{birth}$$isvalidfortheMilkyWaydiskandsimilarlystructuredgalaxies,whereweexpectR$_$\text{birth}$$ can be recovered to within 20% assuming today’s measurement uncertainties in TNG50.