Reconciling the results of the <i>z</i> ∼ 2 MOSDEF and KBSS-MOSFIRE Surveys

The combination of the MOSDEF and KBSS-MOSFIRE surveys represents the largest joint investment of Keck/MOSFIRE time to date, with similar to 3000 galaxies at 1.4 less than or similar to z less than or similar to 3.8, roughly half of which are at z similar to 2. MOSDEF is photometric- and spectroscopic-redshift selected with a rest-optical magnitude limit, while KBSS-MOSFIRE is primarily selected based on rest-UV colours and a rest-UV magnitude limit. Analysing both surveys in a uniform manner with consistent spectral-energy-distribution (SED) models, we find that the MOSDEF z similar to 2 targeted sample has higher median M-* and redder rest U-V colour than the KBSS-MOSFIRE z similar to 2 targeted sample, and smaller median SED-based SFR and sSFR (SFR(SED) and sSFR(SED)). Specifically, MOSDEF targeted a larger population of red galaxies with U-V and V-J >= 1.25, while KBSS-MOSFIRE contains more young galaxies with intense star formation. Despite these differences in the z similar to 2 targeted samples, the subsets of the surveys with multiple emission lines detected and analysed in previous work are much more similar. All median host-galaxy properties with the exception of stellar population age - i.e. M-*, SFR(SED), sSFR(SED), A(V), and UVJ colours - agree within the uncertainties. Additionally, when uniform emission-line fitting and stellar Balmer absorption correction techniques are applied, there is no significant offset between both samples in the [O iii]lambda 5008/H beta versus [N ii]lambda 6585/H alpha diagnostic diagram, in contrast to previously reported discrepancies. We can now combine the MOSDEF and KBSS-MOSFIRE surveys to form the largest z similar to 2 sample with moderate-resolution rest-optical spectra and construct the fundamental scaling relations of star-forming galaxies during this important epoch.