Physical properties of spectroscopically confirmed galaxies at z ≥ 6. III. Stellar populations from sed modeling with secure Lyα emission and redshifts

Linhua Jiang, Kristian Finlator, Seth H. Cohen, Eiichi Egami, Rogier Windhorst, Xiaohui Fan, Romeel Davé, Nobunari Kashikawa, Matthew Mechtley, Masami Ouchi, Kazuhiro Shimasaku, Benjamin Clément

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

We present a study of stellar populations in a sample of spectroscopically confirmed Lyman-break galaxies (LBGs) and Lyα emitters (LAEs) at 5.7 <z <7. These galaxies have deep images from Subaru, the Hubble Space Telescope, and Spitzer/IRAC. We focus on 27 galaxies with IRAC detections, and characterize their stellar populations based on the multi-band data and secure redshifts. By estimating nebular emission from the observed Lyα flux, we break the strong model degeneracy between young galaxies with prominent nebular emission and older galaxies with strong Balmer breaks. The results show that our galaxies cover a wide range of ages from several to a few hundred million years (Myr), and stellar masses from ∼108 to ∼1011 M. These galaxies can be roughly divided into two subsamples: an "old" subsample consisting of galaxies older than 100 Myr, with stellar masses higher than 109 M and a "young" subsample consisting of galaxies younger than ∼30 Myr, with masses ranging between ∼108 and ∼3 × 109 M. Both subsamples display a correlation between stellar mass and star formation rate (SFR), but with very different normalizations. The average specific SFR (sSFR) of the "old" subsample is 3-4 Gyr-1, consistent with previous studies of "normal" star-forming galaxies at z ≥ 6. The average sSFR of the "young" subsample is an order of magnitude higher, likely due to starburst activity. Our results also indicate little dust extinction in the majority of the galaxies, as already suggested by their steep rest-frame UV slopes. Finally, LAEs and LBGs with strong Lyα emission are indistinguishable in terms of age, stellar mass, and SFR.

Original languageEnglish (US)
Article number16
JournalAstrophysical Journal
Volume816
Issue number1
DOIs
StatePublished - Jan 1 2016

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physical property
physical properties
galaxies
modeling
stellar mass
star formation rate
extinction
dust
emitters
young
Hubble Space Telescope
estimating
rate
slopes
stars

Keywords

  • galaxies: evolution
  • galaxies: high-redshift

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Physical properties of spectroscopically confirmed galaxies at z ≥ 6. III. Stellar populations from sed modeling with secure Lyα emission and redshifts. / Jiang, Linhua; Finlator, Kristian; Cohen, Seth H.; Egami, Eiichi; Windhorst, Rogier; Fan, Xiaohui; Davé, Romeel; Kashikawa, Nobunari; Mechtley, Matthew; Ouchi, Masami; Shimasaku, Kazuhiro; Clément, Benjamin.

In: Astrophysical Journal, Vol. 816, No. 1, 16, 01.01.2016.

Research output: Contribution to journalArticle

Jiang, L, Finlator, K, Cohen, SH, Egami, E, Windhorst, R, Fan, X, Davé, R, Kashikawa, N, Mechtley, M, Ouchi, M, Shimasaku, K & Clément, B 2016, 'Physical properties of spectroscopically confirmed galaxies at z ≥ 6. III. Stellar populations from sed modeling with secure Lyα emission and redshifts', Astrophysical Journal, vol. 816, no. 1, 16. https://doi.org/10.3847/0004-637X/816/1/16
Jiang, Linhua ; Finlator, Kristian ; Cohen, Seth H. ; Egami, Eiichi ; Windhorst, Rogier ; Fan, Xiaohui ; Davé, Romeel ; Kashikawa, Nobunari ; Mechtley, Matthew ; Ouchi, Masami ; Shimasaku, Kazuhiro ; Clément, Benjamin. / Physical properties of spectroscopically confirmed galaxies at z ≥ 6. III. Stellar populations from sed modeling with secure Lyα emission and redshifts. In: Astrophysical Journal. 2016 ; Vol. 816, No. 1.
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AU - Davé, Romeel

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