Inferring Galactic parameters from chemical abundances with simulation-based inference

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Table 1

Free CHEMPY parameters and their priors.

Parameter	Description	${\bar{θ}}_{prior} \pm σ_{prior}$ $\[\bar{\theta}_{\text {prior}} \pm \sigma_{\text {prior}}\]$	Prior from:
Λ: Global stellar (SSP) parameters

α_IMF	High-mass slope of the (Chabrier 2003) IMF	−2.3 ± 0.3	(Chabrier 2003, Table 1)
log₁₀ (N_Ia)	Number of SN Ia per M_⊙ over 15 Gyr	−2.89 ± 0.3	(Maoz & Mannucci 2012, Table 1)

Θ_i: Local ISM parameters

log₁₀ (SFE)	Star formation efficiency governing gas infall	−0.3 ± 0.3	(Bigiel et al. 2008)
log₁₀ (SFR_peak)	SFR peak in Gyr (scale of k = 2 Γ-distribution)	0.55 ± 0.1	(van Dokkum et al. 2013, Fig. 4b)
x_out	Stellar feedback fraction	0.5 ± 0.1	(Rybizki et al. 2017, Table 1)

T_i: Timescale

T_i	Time of stellar birth in Gyr	[1,13.8]	Observations

Notes. The table lists the free CHEMPY parameters for each star, with their prior values and Gaussian widths. Stellar birth-times are set for each star individually from a Uniform prior, based on realistic age estimates.

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