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

Gavazzi, R.; Cooray, A.; Conley, A.; Aguirre, J. E.; Amblard, A.; Auld, R.; Beelen, A.; Blain, A.; Blundell, R.; Bock, J.; Bradford, C. M.; Bridge, C.; Brisbin, D.; Burgarella, D.; Chanial, P.; Chapin, E.; Christopher, N.; Clements, D. L.; Cox, P.; Djorgovski, S. G.; Dowell, C. D.; Eales, S.; Earle, L.; Ellsworth-Bowers, T. P.; Farrah, D.; Franceschini, A.; Fu, H.; Glenn, J.; González Solares, E. A.; Griffin, M.; Gurwell, M. A.; Halpern, M.; Ibar, E.; Ivison, R. J.; Jarvis, M.; Kamenetzky, J.; Kim, S.; Krips, M.; Levenson, L.; Lupu, R.; Mahabal, A.; Maloney, P. D.; Maraston, C.; Marchetti, L.; Marsden, G.; Matsuhara, H.; Mortier, A. M. J.; Murphy, E.; Naylor, B. J.; Neri, R.; Nguyen, H. T.; Oliver, S. J.; Omont, A.; Page, M. J.; Papageorgiou, A.; Pearson, C. P.; Pérez-Fournon, I.; Pohlen, M.; Rangwala, N.; Rawlings, J. I.; Raymond, G.; Riechers, D.; Rodighiero, G.; Roseboom, I. G.; Rowan-Robinson, M.; Schulz, B.; Scott, Douglas; Scott, K. S.; Serra, P.; Seymour, N.; Shupe, D. L.; Smith, A. J.; Symeonidis, M.; Tugwell, K. E.; Vaccari, M.; Valiante, E.; Valtchanov, I.; Verma, A.; Vieira, J. D.; Vigroux, L.; Wang, L.; Wardlow, J.; Wiebe, D.; Wright, G.; Xu, C. K.; Zeimann, G.; Zemcov, M.; Zmuidzinas, J.
Bibliographical reference

The Astrophysical Journal, Volume 738, Issue 2, article id. 125 (2011).

Advertised on:
9
2011
Number of authors
88
IAC number of authors
1
Citations
30
Refereed citations
28
Description
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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Formation and Evolution of Galaxies: Observations in Infrared and other Wavelengths
This IAC research group carries out several extragalactic projects in different spectral ranges, using space as well as ground-based telescopes, to study the cosmological evolution of galaxies and the origin of nuclear activity in active galaxies. The group is a member of the international consortium which built the SPIRE instrument for the
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