The NIRVANDELS Survey: a robust detection of $\alpha$-enhancement in star-forming galaxies at $z\simeq3.4$.

We present results from the NIRVANDELS survey investigating the gas-phase metallicity ($\mathrm{Z}_{\mathrm{gas}}$, tracing O/H) and stellar metallicity ($Z_{\star}$, tracing Fe/H) of 33 star-forming galaxies at redshifts $2.95 3$, finding $\mathrm{(O/Fe)}\simeq (2.54 \pm 0.38) \times \mathrm{(O/Fe)}_{\odot}$, with no clear dependence on $M_{\star}$.