Durham University

Department of Physics

Staff profile

Publication details for Professor Ian Smail

Suzuki, Tomoko L., Kodama, Tadayuki, Onodera, Masato, Shimakawa, Rhythm, Hayashi, Masao, Tadaki, Ken-ichi, Koyama, Yusei, Tanaka, Ichi, Sobral, David, Smail, Ian, Best, Philip N., Khostovan, Ali A., Minowa, Yosuke & Yamamoto, Moegi (2017). The Interstellar Medium in [O iii]-selected Star-forming Galaxies at z ∼ 3.2. The Astrophysical Journal 849(1): 39.

Author(s) from Durham


We present new results from near-infrared spectroscopy with Keck/MOSFIRE of [O III]-selected galaxies
at z ~ 3.2. With our H and K band spectra, we investigate the interstellar medium (ISM) conditions,
such as ionization states and gas metallicities. [O III] emitters at z ~ 3.2 show a typical gas metallicity
of 12 log O H 8.07 0.07 + = ( ) at * log 9.0 9. () – M M ~ 2 and 12 log O H 8.31 0.04 + = ( ) at
* log 9.7 10.2 () – M M ~ when using the empirical calibration method. We compare the [O III] emitters at
z ~ 3.2 with UV-selected galaxies and Lyα emitters at the same epoch and find that the [O III]-based selection
does not appear to show any systematic bias in the selection of star-forming galaxies. Moreover, comparing with
star-forming galaxies at z ~ 2 from the literature, our samples show similar ionization parameters and gas
metallicities as those obtained by the previous studies that used the same calibration method. We find no strong
redshift evolution in the ISM conditions between z ~ 3.2 and z ~ 2. Considering that the star formation rates at a
fixed stellar mass also do not significantly change between the two epochs, our results support the idea that the
stellar mass is the primary quantity to describe the evolutionary stages of individual galaxies at z > 2.