Bayesian hierarchical modelling of the $\mathrm{M_{\star}}$-SFR relation from 1<z<6 in ASTRODEEP

Understand

The Hubble Frontier Fields represent the opportunity to probe the high-redshift evolution of the main sequence of star-forming galaxies to lower masses than possible in blank fields thanks to foreground lensing of massive galaxy clusters.

• We use the BEAGLE SED-fitting code to derive stellar masses, $\mathrm{M_{\star}}=\log(M/\mathrm{M_{\odot}})$, SFRs, $\Psi=\log(\psi/\mathrm{M_{\odot}}\,\mathrm{yr}^{-1})$ and redshifts from galaxies within the ASTRODEEP catalogue.
• We fit a fully Bayesian hierarchical model of the main sequence over $1.25<z<6$ of the form $\Psi = \alpha_\mathrm{9.7}(z) + \beta(\mathrm{M_{\star}}-9.7) + \mathcal{N}(0,\sigma^2)$ while explicitly modelling the outlier distribution.
• The redshift-dependent intercept at $\mathrm{M_{\star}}=9.7$ is parametrized as $\alpha_\mathrm{9.7}(z) = \log[N (1+z)^{\gamma}] + 0.7$.