The CFHTLS strong lensing legacy survey. I. Survey overview and T0002 release sample

Rémi A. Cabanac (1) , Ch. Alard (2) , M. Dantel-Fort (2) , B. Fort (3) , Raphaël Gavazzi (4) , P. Gomez (5) , Jean-Paul Kneib (6) , Olivier Le Fèvre (6) , Yannick Mellier (3, 2) , R. Pello (4) , Geneviève Soucail (4) , J.-F. Sygnet (3) , David Valls-Gabaud (1, 4, 7, 8)

1 CFHT - Canada-France-Hawaii Telescope Corporation
2 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
3 IAP - Institut d'Astrophysique de Paris
4 LATT - Laboratoire Astrophysique de Toulouse-Tarbes
5 Gemini Observatory
6 LAM - Laboratoire d'Astrophysique de Marseille
7 GEPI - Galaxies, Etoiles, Physique, Instrumentation
8 Physique des Galaxies et Cosmologie

Aims:We present data from the CFHTLS Strong Lensing Legacy Survey (SL2S). Due to the unsurpassed combined depth, area and image quality of the Canada-France-Hawaii Legacy Survey it is becoming possible to uncover a large, statistically well-defined sample of strong gravitational lenses which spans the dark halo mass spectrum predicted by the concordance model from galaxy to cluster haloes.
Methods: We describe the development of several automated procedures to find strong lenses of various mass regimes in CFHTLS images.
Results: The preliminary sample of about 40 strong lensing candidates discovered in the CFHTLS T0002 release, covering an effective field of view of 28 deg² is presented. These strong lensing systems were discovered using an automated search and consist mainly of gravitational arc systems with splitting angles between 2 and 15 arcsec. This sample shows for the first time that it is possible to uncover a large population of strong lenses from galaxy groups with typical halo masses of about 10¹³~h^-1~M_&sun;. We discuss the future evolution of the SL2S project and its main scientific aims for the next 3 years, in particular our observational strategy to extract the hundreds of gravitational rings also present in these fields.

Domaines: Astrophysique [astro-ph]

Rémi A. Cabanac, Ch. Alard, M. Dantel-Fort, B. Fort, Raphaël Gavazzi, et al.. The CFHTLS strong lensing legacy survey. I. Survey overview and T0002 release sample. Astronomy and Astrophysics - A&A, 2007, 461, pp.813-821. ⟨10.1051/0004-6361:20065810⟩. ⟨hal-03785063⟩