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A wide area survey for high-redshift massive galaxies. II. Near-infrared spectroscopy of BzK-selected massive star-forming galaxies

Onodera, M.; Arimoto, N.; Daddi, E.; Renzini, A.; Kong, X.; Cimatti, A.; Broadhurst, T.; Alexander, D.M.

A wide area survey for high-redshift massive galaxies. II. Near-infrared spectroscopy of BzK-selected massive star-forming galaxies Thumbnail


M. Onodera

N. Arimoto

E. Daddi

A. Renzini

X. Kong

A. Cimatti

T. Broadhurst


Results are presented from near-infrared spectroscopic observations of a sample of BzK-selected, massive star-forming galaxies (sBzKs) at 1.5 < z < 2.3 that were obtained with OHS/CISCO at the Subaru telescope and with SINFONI at the Very Large Telescope. Among the 28 sBzKs observed, Hα emission was detected in 14 objects, and for 11 of them the [N II] λ6583 flux was also measured. Multiwavelength photometry was also used to derive stellar masses and extinction parameters, whereas Hα and [N II] emissions have allowed us to estimate star formation rates (SFRs), metallicities, ionization mechanisms, and dynamical masses. In order to enforce agreement between SFRs from Hα with those derived from rest-frame UV and mid-infrared, additional obscuration for the emission lines (that originate in H II regions) was required compared to the extinction derived from the slope of the UV continuum. We have also derived the stellar mass-metallicity relation, as well as the relation between stellar mass and specific SFR (SSFR), and compared them to the results in other studies. At a given stellar mass, the sBzKs appear to have been already enriched to metallicities close to those of local star-forming galaxies of similar mass. The sBzKs presented here tend to have higher metallicities compared to those of UV-selected galaxies, indicating that near-infrared selected galaxies tend to be a chemically more evolved population. The sBzKs show SSFRs that are systematically higher, by up to ~2 orders of magnitude, compared to those of local galaxies of the same mass. The empirical correlations between stellar mass and metallicity, and stellar mass and SSFR are then compared with those of evolutionary population synthesis models constructed either with the simple closed-box assumption, or within an infall scenario. Within the assumptions that are built-in such models, it appears that a short timescale for the star formation (sime100 Myr) and large initial gas mass appear to be required if one wants to reproduce both relations simultaneously. Based on data collected at the Subaru telescope, which is operated by the National Astronomical Observatory of Japan (S04A-081, S05A-098), and on observations collected at the European Southern Observatory, Paranal, Chile (075.A-0439).

Journal Article Type Article
Publication Date May 1, 2010
Deposit Date Apr 8, 2013
Publicly Available Date Aug 12, 2014
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 715
Issue 1
Pages 385-405
Keywords Galaxies, Abundances, Evolution, High-redshift, Star formation.
Public URL


Published Journal Article (2.7 Mb)

Copyright Statement
© 2010. The American Astronomical Society. All rights reserved.

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