The Mass-Metallicity Relation of a z ~ 2 Protocluster with MOSFIRE
Abstract
We present Keck/MOSFIRE observations of the role of environment in the formation of galaxies at z ~ 2. Using K-band spectroscopy of Hα and [N ii] emission lines, we have analyzed the metallicities of galaxies within and around a z = 2.3 protocluster discovered in the HS1700+643 field. Our main sample consists of 23 protocluster and 20 field galaxies with estimates of stellar masses and gas-phase metallicities based on the N2 strong-line metallicity indicator. With these data we have examined the mass–metallicity relation with respect to environment at z ~ 2. We find that field galaxies follow the well-established trend between stellar mass and metallicity, such that more massive galaxies have larger metallicities. The protocluster galaxies, however, do not exhibit a dependence of metallicity on mass, with the low-mass protocluster galaxies showing an enhancement in metallicity compared to field galaxies spanning the same mass range. A comparison with galaxy formation models suggests that the mass-dependent environmental trend we observed can be qualitatively explained in the context of the recycling of "momentum-driven" galaxy wind material. Accordingly, winds are recycled on a shorter timescale in denser environments, leading to an enhancement in metallicity at fixed mass for all but the most massive galaxies. Future hydrodynamical simulations of z ~ 2 overdensities matching the one in the HS1700 field will be crucial for understanding the origin of the observed environmental trend in detail.
Additional Information
© 2013 The American Astronomical Society. Received 2013 June 21; accepted 2013 August 2; published 2013 August 23. MOSFIRE was developed by the consortium of the University of California, Los Angeles, the California Institute of Technology, the University of California, Santa Cruz and the W. M. Keck Observatory. Funding was provided by a grant from the National Science Foundation's Telescope System Instrumentation Program and by a generous donation from Gordon and Betty Moore to the Keck Observatory. We thank the entire MOSFIRE team, whose dedication and hard work made this project possible. We also gratefully acknowledge the outstanding support of the entire Keck Observatory staff during commissioning, especially Marc Kassis, Greg Wirth and Al Honey. A.E.S. acknowledges support from the David and Lucile Packard Foundation. N.P.K. acknowledges support from the NSF grant 1106171. Additionally, we acknowledge Romeel Davé for insightful conversations. Finally, we wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, most of the observations presented herein would not have been possible.Attached Files
Published - Kulas_2013p130.pdf
Submitted - 1306.6334v2.pdf
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Additional details
- Eprint ID
- 41605
- Resolver ID
- CaltechAUTHORS:20131002-100802038
- NSF
- Gordon and Betty Moore Foundation
- David and Lucile Packard Foundation
- AST-1106171
- NSF
- Created
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2013-10-02Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field