A SEARCH FOR C II 158 {mu}m LINE EMISSION IN HCM 6A, A Ly{alpha} EMITTER AT z = 6.56

Journal Article · Wed Jul 10 04:00:00 EDT 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/771/2/L20· OSTI ID:22118705

Kanekar, Nissim ^[1]; Wagg, Jeff ^[2]; Chary, Ranga Ram ^[3]

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1. National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007 (India)
2. European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile)
3. U.S. Planck Data Center, MS220-6 Caltech, Pasadena, CA 91125 (United States)

We report a Plateau de Bure Interferometer search for C II 158 {mu}m emission from HCM 6A, a lensed Ly{alpha} emitter (LAE) at z = 6.56. Our non-detections of C II 158 {mu}m line emission and 1.2 mm radio continuum emission yield 3{sigma} limits of L{sub CII} < 6.4 x 10{sup 7} x ({Delta}V/100 km s{sup -1}){sup 1/2} L{sub Sun} for the C II 158 {mu}m line luminosity and S{sub 1.2mm} < 0.68 mJy for the 1.2 mm flux density. The local conversion factor between L{sub CII} and the star formation rate (SFR) yields an SFR < 4.7 M{sub Sun} yr{sup -1}, Almost-Equal-To 2 times lower than that inferred from the ultraviolet (UV) continuum, suggesting that the local factor may not be applicable in high-z LAEs. The non-detection of 1.2 mm continuum emission yields a total SFR < 28 M{sub Sun} yr{sup -1}; any obscured star formation is thus within a factor of two of the visible star formation. Our best-fit model to the rest-frame UV/optical spectral energy distribution of HCM 6A yields a stellar mass of 1.3 Multiplication-Sign 10{sup 9} M{sub Sun} and an SFR of Almost-Equal-To 10 M{sub Sun} yr{sup -1}, with negligible dust obscuration. We fortuitously detect CO J = 3-2 emission from a z = 0.375 galaxy in the foreground cluster A370, and obtain a CO line luminosity of L'(CO) > (8.95 {+-} 0.79) Multiplication-Sign 10{sup 8} K km s{sup -1} pc{sup 2} and a molecular gas mass of M(H{sub 2}) > (4.12 {+-} 0.36) Multiplication-Sign 10{sup 9} M{sub Sun }, for a CO-to-H{sub 2} conversion factor of 4.6 M{sub Sun} (K km s{sup -1} pc{sup 2}){sup -1}.

• OSTI ID: 22118705
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 771; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
CARBON IONS
CARBON MONOXIDE
COSMIC DUST
COSMOLOGY
ENERGY SPECTRA
FLUX DENSITY
GALACTIC EVOLUTION
GALAXIES
HYDROGEN
INTERFEROMETRY
LUMINOSITY
LYMAN LINES
MASS
PHOTON EMISSION
RADIATION DETECTION
STAR EVOLUTION
STARS
ULTRAVIOLET RADIATION