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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 710087.0, MPI für Astronomie / Publikationen_mpia
ALMA observation of 158 mm [C II] line and dust continuum of a z = 7 normally star-forming galaxy in the epoch of reionization
Authors:Ota, K.; Walter, F.; Ohta, K.; Hatsukade, B.; Carilli, C. L.; da Cunha, E.; González-López, J.; Decarli, R.; Hodge, J. A.; Nagai, H.; Egami, E.; Jiang, L.; Iye, M.; Kashikawa, N.; Riechers, D. A.; Bertoldi, F.; Cox, P.; Neri, R.; Weiss, A.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:The Astrophysical Journal
Issue / Number:1
Start Page:id. 34 (13 pp)
Audience:Not Specified
Abstract / Description:We present ALMA observations of the [C II] line and far-infrared (FIR) continuum of a normally star-forming galaxy in the reionization epoch, the z = 6.96 Lyalpha emitter (LAE) IOK-1. Probing to sensitivities of sigmaline = 240 muJy beam--1 (40 km s--1 channel) and sigmacont = 21 muJy beam--1, we found the galaxy undetected in both [C II] and continuum. Comparison of ultraviolet (UV)-FIR spectral energy distribution (SED) of IOK-1, including our ALMA limit, with those of several types of local galaxies (including the effects of the cosmic microwave background, CMB, on the FIR continuum) suggests that IOK-1 is similar to local dwarf/irregular galaxies in SED shape rather than highly dusty/obscured galaxies. Moreover, our 3sigma FIR continuum limit, corrected for CMB effects, implies intrinsic dust mass M dust < 6.4 × 107 M &#9737;, FIR luminosity L FIR < 3.7 × 1010 L &#9737; (42.5-122.5 mum), total IR luminosity L IR < 5.7 × 1010 L &#9737; (8-1000 mum), and dust-obscured star formation rate (SFR) < 10 M &#9737; yr--1, if we assume that IOK-1 has a dust temperature and emissivity index typical of local dwarf galaxies. This SFR is 2.4 times lower than one estimated from the UV continuum, suggesting that <29% of the star formation is obscured by dust. Meanwhile, our 3sigma [C II] flux limit translates into [C II] luminosity, L [C II] < 3.4 × 107 L &#9737;. Locations of IOK-1 and previously observed LAEs on the L [C II] versus SFR and L [C II]/L FIR versus L FIR diagrams imply that LAEs in the reionization epoch have significantly lower gas and dust enrichment than AGN-powered systems and starbursts at similar/lower redshifts, as well as local star-forming galaxies. Based in part on data collected with the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555; and observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Free Keywords:cosmology: observations; early universe; galaxies: evolution; galaxies: formation
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-637X %R 10.1088/0004-637X/792/1/34
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