HerMES: Candidate Gravitationally Lensed Galaxies and Lensing Statistics at Submillimeter Wavelengths

Rigopoulou, D.; Roseboom, I. G.; Rowan-Robinson, M.; Zemcov, M.; Yan, L.; Xu, C. K.; Wang, L.; Scott, D.; Schulz, B.; Seymour, N.; Scoville, N.; Riechers, D.; Pohlen, M.; Viero, M.; Vieira, J. D.; Trichas, M.; Symeonidis, M.; Strom, A.; Shupe, D. L.; Smith, A. J.; Streblyanska, A.; Vaccari, M.; Pérez-Fournon, I.; Pearson, C. P.; Papageorgiou, A.; Panuzzo, P.; Page, M. J.; Omont, A.; Oliver, S. J.; O'Halloran, B.; Nguyen, H. T.; Neri, R.; Negrello, M.; Martínez-Navajas, P.; Marsden, G.; Marchetti, L.; Levenson, L.; Lagache, G.; Kim, S.; Ivison, R. J.; Ibar, E.; Hyde, A.; Hopwood, R.; Hatziminaoglou, E.; Harris, A. I.; Gurwell, M. A.; Griffin, M.; González Solares, E. A.; Glenn, J.; Gavazzi, R.; Fu, Hai; Frazer, C.; Frayer, D. T.; Franceschini, A.; Ferrero, P.; Farrah, D.; Eales, S.; Dye, S.; Dowell, C. D.; Cox, P.; Conley, A.; Clements, D. L.; Chapman, S. C.; Chapin, E.; Chanial, P.; Cava, A.; Castro-Rodríguez, N.; Casey, C. M.; Carpenter, J. M.; Calanog, J.; Cabrera-Lavers, A.; Bussmann, R. S.; Burgarella, D.; Buat, V.; Bridge, C.; Boselli, A.; Bock, J.; Blundell, R.; Béthermin, M.; Baker, A. J.; Aussel, H.; Arumugam, V.; Amblard, A.; De Bernardis, Francesco; Cooray, Asantha; Wardlow, Julie L.
Bibliographical reference

The Astrophysical Journal, Volume 762, Issue 1, article id. 59, 28 pp. (2013).

Advertised on:
1
2013
Number of authors
86
IAC number of authors
6
Citations
170
Refereed citations
155
Description
We present a list of 13 candidate gravitationally lensed submillimeter galaxies (SMGs) from 95 deg2 of the Herschel Multi-tiered Extragalactic Survey, a surface density of 0.14 ± 0.04 deg–2. The selected sources have 500 μm flux densities (S 500) greater than 100 mJy. Gravitational lensing is confirmed by follow-up observations in 9 of the 13 systems (70%), and the lensing status of the four remaining sources is undetermined. We also present a supplementary sample of 29 (0.31 ± 0.06 deg–2) gravitationally lensed SMG candidates with S 500 = 80-100 mJy, which are expected to contain a higher fraction of interlopers than the primary candidates. The number counts of the candidate lensed galaxies are consistent with a simple statistical model of the lensing rate, which uses a foreground matter distribution, the intrinsic SMG number counts, and an assumed SMG redshift distribution. The model predicts that 32%-74% of our S 500 >= 100 mJy candidates are strongly gravitationally lensed (μ >= 2), with the brightest sources being the most robust; this is consistent with the observational data. Our statistical model also predicts that, on average, lensed galaxies with S 500 = 100 mJy are magnified by factors of ~9, with apparently brighter galaxies having progressively higher average magnification, due to the shape of the intrinsic number counts. 65% of the sources are expected to have intrinsic 500 μm flux densities less than 30 mJy. Thus, samples of strongly gravitationally lensed SMGs, such as those presented here, probe below the nominal Herschel detection limit at 500 μm. They are good targets for the detailed study of the physical conditions in distant dusty, star-forming galaxies, due to the lensing magnification, which can lead to spatial resolutions of ~0.''01 in the source plane.
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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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