Stellar and Dust Properties of a Complete Sample of Massive Dusty Galaxies at 1 ≤ z ≤ 4 from MAGPHYS Modeling of UltraVISTA DR3 and Herschel Photometry

Abstract

We investigate the stellar and dust properties of massive (log M ∗/M o ≥ 10.5) and dusty (A V ≥ 1) galaxies at 1 ≤ z ≤ 4 by modeling their spectral energy distributions (SEDs) obtained from the combination of UltraVISTA DR3 photometry and Herschel PACS-SPIRE data using MAGPHYS. Although the rest-frame U-V versus V-J (UVJ) diagram traces the star formation rates (SFRs) and dust obscuration (A V) well out to z ∼ 3, ∼15%-20% of the sample surprisingly resides in the quiescent region of the UVJ diagram, while ∼50% at 3 < z < 4 falls in the unobscured star-forming region. The median SED of massive dusty galaxies exhibits weaker MIR and UV emission, and redder UV slopes with increasing cosmic time. The IR emission for our sample has a significant contribution (>20%) from dust heated by evolved stellar populations rather than star formation, demonstrating the need for panchromatic SED modeling. The local relation between dust mass and SFR is followed only by a subsample with cooler dust temperatures, while warmer objects have reduced dust masses at a given SFR. Most star-forming galaxies in our sample do not follow local IRX-β relations, though IRX does strongly correlate with A V. Our sample follows local relations, albeit with large scatter, between ISM diagnostics and sSFR. We show that FIR-detected sources represent the extreme of a continuous population of dusty galaxies rather than a fundamentally different population. Finally, using commonly adopted relations to derive SFRs from the combination of the rest-frame UV and the observed 24 μm is found to overestimate the SFR by a factor of 3-5 for the galaxies in our sample.