MOIRCS Deep Survey. VI. Near-Infrared Spectroscopy of K-Selected Star-Forming Galaxies at z~2 - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




MOIRCS Deep Survey. VI. Near-Infrared Spectroscopy of K-Selected Star-Forming Galaxies at z~2 - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We present near-infrared NIR spectroscopy for 37 BzK-color-selectedstar-forming galaxies with MOIRCS on Subaru. The sample is drawn from theKs-band selected catalog of the MOIRCS Deep Survey MODS in the GOODS-Nregion. About half of our samples are selected from the MIPS 24um-sourcecatalog. Ha emission lines are detected from 23 galaxies, of which the medianredshift is 2.12. We derived the star formation rates SFRs fromextinction-corrected Ha luminosities. The extinction correction is estimatedfrom the SED fitting of multi-band photometric data covering UV to NIRwavelengths. The Balmer decrement of the stacked emission lines shows that theamount of extinction for the ionized gas is larger than that for the stellarcontinuum. From a comparison of the extinction corrected Ha luminosity andother SFR indicators we found that the relation between the dust properties ofstellar continuum and ionized gas is different depending on the intrinsic SFR.The comparison between the Ha SFR and stellar mass estimated from SED fittingshows no correlation between them. Some galaxies with stellar mass smaller than~10^10 Msun show SFRs higher than ~100 Msun-yr. The specific SFRs SSFRs ofthese galaxies are remarkably high. The average stellar-population age of thesehigh-SSFR galaxies is younger than 100 Myr, which is consistent with theimplied high SSFR. The large SFR implies the possibility that the high SSFRgalaxies significantly contribute to the cosmic SFR density of the universe atz~2. The total SFR density estimated from the Ha emission line galaxies is0.089-0.136 Msun-yr-Mpc^3, which is consistent with the total SFR densities inthe literature. The metallicity of the high-SSFR galaxies is larger than thatexpected from the mass-metallicity relation of UV-selected galaxies at z~2 byErb et al. 2006a. Abridged



Author: Tomohiro Yoshikawa, Masayuki Akiyama, Masaru Kajisawa, David M. Alexander, Kouji Ohta, Ryuji Suzuki, Chihiro Tokoku, Yuka K. Uchi

Source: https://arxiv.org/



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