TY - JOUR
T1 - Zfourge
T2 - Extreme 5007 Å Emission May Be a Common Early-lifetime Phase for Star-forming Galaxies at z > 2.5
AU - Cohn, Jonathan H.
AU - Leja, Joel
AU - Tran, Kim Vy H.
AU - Forrest, Ben
AU - Johnson, Benjamin D.
AU - Tillman, Megan
AU - Alcorn, Leo
AU - Conroy, Charlie
AU - Glazebrook, Karl
AU - Kacprzak, Glenn G.
AU - Kelson, Daniel D.
AU - Nanayakkara, Themiya
AU - Papovich, Casey
AU - Van Dokkum, Pieter G.
AU - Yuan, Tiantian
N1 - Funding Information:
We wish to thank the Mitchell family for their continuing support of astronomy. We also thank the Carnegie Observatories and the Las Campanas Observatory for their assistance in making the ZFOURGE survey possible. K. Tran thanks P. Oesch, B. Holden, and M. Maseda for helpful discussions and acknowledges support by the National Science Foundation under grant #1410728. G.G.K. acknowledges the support of the Australian Research Council through the award of a Future Fellowship (FT140100933). B.F. thanks the Hagler Institute for Advanced Study at Texas A&M. J.H.C. thanks T. Hutchison for constructive comments on the first draft. Portions of this research were conducted with high performance research computing resources provided by Texas A&M University (https://hprc. tamu.edu). We also thank the anonymous referee for valuable comments that improved the manuscript.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..
PY - 2018/12/20
Y1 - 2018/12/20
N2 - Using the Prospector spectral energy distribution (SED) fitting code, we analyze the properties of 19 extreme emission-line galaxies (EELGs) identified in the bluest composite SED in the zfourge survey at 2.5 ≤ z ≤ 4. Prospector includes a physical model for nebular emission and returns probability distributions for stellar mass, stellar metallicity, dust attenuation, and nonparametric star formation history (SFH). The EELGs show evidence of a starburst in the most recent 50 Myr, with the median EELG having a specific star formation rate (sSFR) of 4.6 Gyr-1 and forming 15% of its mass in this short time. For a sample of more typical star-forming galaxies (SFGs) at the same redshifts, the median SFG has an sSFR of 1.1 Gyr-1 and forms only 4% of its mass in the last 50 Myr. We find that virtually all of our EELGs have rising SFHs, while most of our SFGs do not. From our analysis, we hypothesize that many, if not most, SFGs at z ≥ 2.5 undergo an extreme Hβ+[O iii] emission-line phase early in their lifetimes. In a companion paper, we obtain spectroscopic confirmation of the EELGs as part of our MOSEL survey. In the future, explorations of uncertainties in modeling the UV slope for galaxies at z > 2 are needed to better constrain their properties, e.g., stellar metallicities.
AB - Using the Prospector spectral energy distribution (SED) fitting code, we analyze the properties of 19 extreme emission-line galaxies (EELGs) identified in the bluest composite SED in the zfourge survey at 2.5 ≤ z ≤ 4. Prospector includes a physical model for nebular emission and returns probability distributions for stellar mass, stellar metallicity, dust attenuation, and nonparametric star formation history (SFH). The EELGs show evidence of a starburst in the most recent 50 Myr, with the median EELG having a specific star formation rate (sSFR) of 4.6 Gyr-1 and forming 15% of its mass in this short time. For a sample of more typical star-forming galaxies (SFGs) at the same redshifts, the median SFG has an sSFR of 1.1 Gyr-1 and forms only 4% of its mass in the last 50 Myr. We find that virtually all of our EELGs have rising SFHs, while most of our SFGs do not. From our analysis, we hypothesize that many, if not most, SFGs at z ≥ 2.5 undergo an extreme Hβ+[O iii] emission-line phase early in their lifetimes. In a companion paper, we obtain spectroscopic confirmation of the EELGs as part of our MOSEL survey. In the future, explorations of uncertainties in modeling the UV slope for galaxies at z > 2 are needed to better constrain their properties, e.g., stellar metallicities.
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UR - http://www.scopus.com/inward/citedby.url?scp=85059859875&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aaed3d
DO - 10.3847/1538-4357/aaed3d
M3 - Article
AN - SCOPUS:85059859875
VL - 869
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 141
ER -