ALMA WILL DETERMINE THE SPECTROSCOPIC REDSHIFT z > 8 WITH FIR [O III] EMISSION LINES

• Published in: Astrophysical journal. Letters Vol. 780; no. 2; pp. 1 - 5
• Main Authors: Inoue, A K, Shimizu, I, Tamura, Y, Matsuo, H, Okamoto, T, Yoshida, N
• Format: Journal Article
• Language: English
• Published: United States 10.01.2014
• Subjects: Arrays; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPUTERIZED SIMULATION; COSMOLOGY; EMISSION; Emission spectroscopy; EMISSIVITY; FAR INFRARED RADIATION; GALACTIC EVOLUTION; GALAXIES; HYDRODYNAMICS; INFRARED SPECTRA; Mathematical models; METALLICITY; OXYGEN IONS; POTENTIALS; Radio telescopes; RED SHIFT; Spectroscopy
• ISSN: 2041-8205; 2041-8213
• DOI: 10.1088/2041-8205/780/2/L18

We investigate the potential use of nebular emission lines in the rest-frame far-infrared (FIR) for determining spectroscopic redshift of z > 8 galaxies with the Atacama Large Millimeter/submillimeter Array (ALMA). After making a line emissivity model as a function of metallicity, especially for the [OIII] 88 mu m line which is likely to be the strongest FIR line from H II regions, we predict the line fluxes from high-z galaxies based on a cosmological hydrodynamics simulation of galaxy formation. Since the metallicity of galaxies reaches at ~0.2 Z sub([middot in circle]) even at z > 8 in our simulation, we expect the [OIII] 88 mu m line as strong as 1.3 mJy for 27 AB objects, which is detectable at a high significance by <1 hr integration with ALMA. Therefore, the [OIII] 88 mu m line would be the best tool to confirm the spectroscopic redshifts beyond z = 8.