A Complete 16 μm Selected Galaxy Sample at z ∼ 1: Mid-infrared Spectral Energy Distributions

J.-S. Huang, Y.-S. Dai, S. P. Willner, S. M. Faber, C. Cheng, H. Xu, H. Yan, S. Wu, X. Shao, C. Hao, X. Xia, D. Rigopoulou, M. Pereira Santaella, G. Magdis, I. Cortzen, G. G. Fazio, P. Assmann, L. Fan, M. Musin, Z. WangK. C. Xu, C. He, G. Jin, A. Esamdin

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We describe a complete, flux-density-limited sample of galaxies at redshift 0.8 < z < 1.3 selected at 16 μm. At the selection wavelength near 8 μm rest, the observed emission comes from both dust heated by intense star formation and active galactic nuclei (AGNs). Fitting the spectral energy distributions (SEDs) of the sample galaxies to local-galaxy templates reveals that more than half the galaxies have SEDs dominated by star formation. About one-sixth of the galaxy SEDs are dominated by an AGN, and nearly all of the rest of the SEDs are composite. Comparison with X-ray and far-infrared observations shows that combinations of luminosities at rest-frame 4.5 and 8 μm give good measures of both AGN luminosity and star formation rate. The sample galaxies mostly follow the established star-forming main sequence for z = 1 galaxies, but of the galaxies more than 0.5 dex above that main sequence, more than half have AGN-type SEDs. Similarly, the most luminous AGNs tend to have higher star formation rates than the main-sequence value. Galaxies with stellar masses >1011 M are unlikely to host an AGN. About 1% of the sample galaxies show an SED with dust emission typical of neither star formation nor an AGN.
Original languageEnglish
Article number161
JournalAstrophysical Journal
Volume912
Issue number2
Number of pages17
ISSN0004-637X
DOIs
Publication statusPublished - 2021

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