THE MOSDEF SURVEY: THE STRONG AGREEMENT BETWEEN H alpha AND UV-TO-FIR STAR FORMATION RATES FOR z similar to 2 STAR-FORMING GALAXIES

摘要

We present the first direct comparison between Balmer line and panchromatic spectral energy distribution (SED)-based star formation rates (SFRs) for z similar to 2 galaxies. For this comparison, we used 17 star-forming galaxies selected from the MOSFIRE Deep Evolution Field (MOSDEF) survey, with 3 sigma detections for H alpha and at least two IR bands (Spitzer/MIPS 24 mu m and Herschel/PACS 100 and 160 mu m, and in some cases Herschel/SPIRE 250, 350, and 500 mu m). The galaxies have total IR (8-1000 mu m) luminosities of similar to 10(11.4)-10(12.4) L-circle dot and SFRs of similar to 30-250 M-circle dot yr(-1).. We fit the UV-to-far-IR SEDs with flexible stellar population synthesis (FSPS) models-which include both stellar and dust emission-and compare the inferred SFRs with the SFR(H alpha, H beta) values corrected for dust attenuation using Balmer decrements. The two SFRs agree with a scatter of 0.17 dex. Our results imply that the Balmer decrement accurately predicts the obscuration of the nebular lines and can be used to robustly calculate SFRs for star-forming galaxies at z similar to 2 with SFRs up to similar to 200 M-circle dot yr(-1).. We also use our data to assess SFR indicators based on modeling the UV-to-mid-IR SEDs or by adding SFR(UV) and SFR(IR), for which the latter is based on the mid-IR only or on the full IR SED. All these SFRs show a poorer agreement with SFR(H alpha, H beta) and in some cases large systematic biases are observed. Finally, we show that the SFR and dust attenuation derived from the UV-to-near-IR SED alone are unbiased when assuming a delayed exponentially declining star formation history.