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A bright z=5.2 lensed submillimeter galaxy in the field of Abell 773 HLSJ091828.6+514223



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Pérez González, Pablo Guillermo and otros, ... (2012) A bright z=5.2 lensed submillimeter galaxy in the field of Abell 773 HLSJ091828.6+514223. Astronomy & Astrophysics, 538 . ISSN 0004-6361


Official URL: http://dx.doi.org/10.1051/0004-6361/201118750



During our Herschel Lensing Survey (HLS) of massive galaxy clusters, we have discovered an exceptionally bright source behind the z = 0.22 cluster Abell 773, which appears to be a strongly lensed submillimeter galaxy (SMG) at z = 5.2429. This source is unusual compared to most other lensed sources discovered by Herschel so far, because of its higher submm flux (∼200 mJy at 500 μm) and its high redshift. The dominant lens is a foreground z = 0.63 galaxy, not the cluster itself. The source has a far-infrared (FIR) luminosity of L_FIR = 1.1 × 10^14/μ L_⨀, where μ is the magnification factor, likely ∼11. We report here the redshift identification through CO lines with the IRAM-30 m, and the analysis of the gas excitation, based on CO(7–6), CO(6–5), CO(5–4) detected at IRAM and the CO(2–1) at the EVLA. All lines decompose into a wide and strong red component, and a narrower and weaker blue component, 540 km s^−1 apart. Assuming the ultraluminous galaxy (ULIRG) CO-to-H_2 conversion ratio, the H_2 mass is 5.8×10^11/μ M_⨀, of which one third is in a cool component. From the CI(^3P_2−^3 P_1) line we derive a C_I/H_2 number abundance of 6 × 10^−5 similar to that in other ULIRGs. The H_2O_p(2, 0, 2−1, 1, 1) line is strong only in the red velocity component, with an intensity ratio I(H_2O)/I(CO) ∼ 0.5, suggesting a strong local FIR radiation field, possibly from an active nucleus (AGN) component. We detect the [NII]205 μm line for the first time at high-z. It shows comparable blue and red components, with a strikingly broad blue one, suggesting strong ionized gas flows.

Item Type:Article
Additional Information:

© ESO, 2012.
Artículo firmado por 23 autores.
IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). Herschel is an ESA space observatory with instruments provided by European-led PI consortia and with important participation from NASA. Support for this work was provided in part by NASA through an award issued by JPL/Caltech. The SMA is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. NRAO is operated by Associated Universities Inc., under a cooperative agreement with the National Science Foundation. The Keck observatory, made possible thanks to the generous support of W. M. Keck Foundation, is operated by Caltech, the University of California, and NASA.

Uncontrolled Keywords:Star-formation history; Ultraluminous infrared galaxies; Molecular gas; Herschel-atlas; APM 08279+5255; Markarian 231; Water-vapor; Interstellar-medium; Massive galaxy; Dark-matter
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:38515
Deposited On:21 Jul 2016 14:32
Last Modified:10 Dec 2018 15:05

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