Modeling of the HerMES Submillimeter Source Lensed by a Dark Matter Dominated Foreground Group of Galaxies

Gavazzi, R. and Cooray, A. and Conley, A. and Aguirre, J. E. and Amblard, A. and Auld, R. and Beelen, A. and Blain, A. and Blundell, R. and Bock, J. and Bradford, C. M. and Bridge, C. and Brisbin, D. and Burgarella, D. and Chanial, P. and Chapin, E. and Christopher, N. and Clements, D. L. and Cox, P. and Djorgovski, S. G. and Dowell, C. D. and Eales, S. and Earle, L. and Ellsworth-Bowers, T. P. and Farrah, D. and Franceschini, A. and Fu, H. and Glenn, J. and González Solares, E. A. and Griffin, M. and Gurwell, M. A. and Halpern, M. and Ibar, E. and Ivison, R. J. and Jarvis, M. and Kamenetzky, J. and Kim, S. and Krips, M. and Levenson, L. and Lupu, R. and Mahabal, A. and Maloney, P. D. and Maraston, C. and Marchetti, L. and Marsden, G. and Matsuhara, H. and Mortier, A. M. J. and Murphy, E. and Naylor, B. J. and Neri, R. and Nguyen, H. T. and Oliver, S. J. and Omont, A. and Page, M. J. and Papageorgiou, A. and Pearson, C. P. and Pérez-Fournon, I. and Pohlen, M. and Rangwala, N. and Rawlings, J. I. and Raymond, G. and Riechers, D. and Rodighiero, G. and Roseboom, I. G. and Rowan-Robinson, M. and Schulz, B. and Scott, Douglas and Scott, K. S. and Serra, P. and Seymour, N. and Shupe, D. L. and Smith, A. J. and Symeonidis, M. and Tugwell, K. E. and Vaccari, M. and Valiante, E. and Valtchanov, I. and Verma, A. and Vieira, J. D. and Vigroux, L. and Wang, L. and Wardlow, J. and Wiebe, D. and Wright, G. and Xu, C. K. and Zeimann, G. and Zemcov, M. and Zmuidzinas, J. (2011) Modeling of the HerMES Submillimeter Source Lensed by a Dark Matter Dominated Foreground Group of Galaxies. The Astrophysical Journal, 738 (2). ISSN 0004-637X

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We present the results of a gravitational lensing analysis of the bright z s = 2.957 submillimeter galaxy (SMG) HERMES found in the Herschel/SPIRE science demonstration phase data from the Herschel Multi-tiered Extragalactic Survey (HerMES) project. The high-resolution imaging available in optical and near-IR channels, along with CO emission obtained with the Plateau de Bure Interferometer, allows us to precisely estimate the intrinsic source extension and hence estimate the total lensing magnification to be μ = 10.9 ± 0.7. We measure the half-light radius R eff of the source in the rest-frame near-UV and V bands that characterize the unobscured light coming from stars and find R eff, * = [2.0 ± 0.1] kpc, in good agreement with recent studies on the SMG population. This lens model is also used to estimate the size of the gas distribution (R eff, gas = [1.1 ± 0.5] kpc) by mapping back in the source plane the CO (J = 5 → 4) transition line emission. The lens modeling yields a relatively large Einstein radius R Ein = 4farcs10 ± 0farcs02, corresponding to a deflector velocity dispersion of [483 ± 16] km s-1. This shows that HERMES is lensed by a galaxy group-size dark matter halo at redshift z l ~ 0.6. The projected dark matter contribution largely dominates the mass budget within the Einstein radius with f dm(<R Ein) ~ 80%. This fraction reduces to f dm(<R eff, G1 ~= 4.5 kpc) ~ 47% within the effective radius of the main deflecting galaxy of stellar mass M *, G1 = [8.5 ± 1.6] × 1011 M sun. At this smaller scale the dark matter fraction is consistent with results already found for massive lensing ellipticals at z ~ 0.2 from the Sloan Lens ACS Survey. Some of the data presented herein were obtained at the W. M. Keck Observatory which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

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Journal Article
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The Astrophysical Journal
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C 2011. The American Astronomical Society. All rights reserved.
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17 Oct 2018 14:14
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02 Aug 2020 05:58