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Dust Attenuation, Star Formation, and Metallicity in z ~ 2-3 Galaxies from KBSS-MOSFIRE

Theios, Rachel L. and Steidel, Charles C. and Strom, Allison L. and Rudie, Gwen C. and Trainor, Ryan F. and Reddy, Naveen A. (2019) Dust Attenuation, Star Formation, and Metallicity in z ~ 2-3 Galaxies from KBSS-MOSFIRE. Astrophysical Journal, 871 (1). Art. No. 128. ISSN 1538-4357. doi:10.3847/1538-4357/aaf386.

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We present a detailed analysis of 317 2.0 ≤ z ≤ 2.7 star-forming galaxies from the Keck Baryonic Structure Survey. Using complementary spectroscopic observations with Keck/LRIS and Keck/MOSFIRE, as well as spectral energy distribution (SED) fits to broadband photometry, we examine the joint rest-UV and rest-optical properties of the same galaxies, including stellar and nebular dust attenuation, metallicity, and star formation rate (SFR). The inferred parameters of the stellar population (reddening, age, SFR, and stellar mass) are strongly dependent on the details of the assumed stellar population model and the shape of the attenuation curve. Nebular reddening is generally larger than continuum reddening, but with large scatter. Compared to local galaxies, high-redshift galaxies have lower gas-phase metallicities (and/or higher nebular excitation) at fixed nebular reddening, and higher nebular reddening at fixed stellar mass, consistent with gas fractions that increase with redshift. We find that continuum reddening is correlated with 12 + log(O/H)_(O3N2) at 3.0σ significance, whereas nebular reddening is correlated with only 1.1σ significance. This may reflect the dependence of both continuum reddening and O3N2 on the shape of the ionizing radiation field produced by the massive stars. Finally, we show that Hα-based and SED-based estimates of SFR exhibit significant scatter relative to one another, and on average agree only for particular combinations of spectral synthesis models and attenuation curves. We find that the SMC extinction curve predicts consistent SFRs if we assume the subsolar (0.14 Z⊙) binary star models that are favored for high-redshift galaxies.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Theios, Rachel L.0000-0002-4236-1037
Steidel, Charles C.0000-0002-4834-7260
Strom, Allison L.0000-0001-6369-1636
Rudie, Gwen C.0000-0002-8459-5413
Trainor, Ryan F.0000-0002-6967-7322
Reddy, Naveen A.0000-0001-9687-4973
Additional Information:© 2019 The American Astronomical Society. Received 2018 April 30; revised 2018 November 8; accepted 2018 November 21; published 2019 January 25. The authors thank Max Pettini and the anonymous referee for helpful comments. This work has been supported in part by the NSF through grants AST-0908805 and AST-1313472 (CCS, RLT, ALS), by the JPL President-Director Fund (CCS, RLT), by the Professor Wallace L. W. Sargent Graduate Fellowship (RLT) and the Troesh Family Distinguished Scholars Fund (also RLT), and by an Alfred P. Sloan Research Fellowship (NAR). Finally, the authors wish to recognize and acknowledge the significant cultural role and reverence that the summit of Maunakea has within the indigenous Hawaiian community. We are privileged to have the opportunity to conduct observations from this mountain.
Group:Astronomy Department
Funding AgencyGrant Number
JPL President and Director's FundUNSPECIFIED
Wallace L. W. Sargent Graduate FellowshipUNSPECIFIED
Troesh Family Distinguished Scholars FundUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Subject Keywords:dust, extinction – galaxies: evolution – galaxies: high-redshift – galaxies: star formation – HII regions – ISM: abundances
Issue or Number:1
Record Number:CaltechAUTHORS:20181129-135233204
Persistent URL:
Official Citation:Rachel L. Theios et al 2019 ApJ 871 128
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91335
Deposited By: George Porter
Deposited On:30 Nov 2018 00:00
Last Modified:16 Nov 2021 03:40

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