Abell 611

I. Weak lensing analysis with LBC

¹ Dipartimento di Fisica, Universitá La Sapienza, piazzale A. Moro 2, 00185 Roma, Italy e-mail: Anna.Romano@roma1.infn.it
² INAF – Osservatorio Astronomico di Roma, via Frascati 33, 00044 Monte Porzio Catone (Roma), Italy
³ INAF – Osservatorio Astronomico di Napoli, via Moiariello 16, 80131 Napoli, Italy
⁴ Key Lab for Astrophysics, Shanghai Normal University, 100 Guilin Road, 200234 Shanghai, PR China
⁵ Dipartimento di Fisica, Universitá Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma, Italy
⁶ Department of Astronomy and Center for Cosmology and Astroparticle Physics, The Ohio State University, Columbus, OH 43210, USA
⁷ INAF – Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, 35122 Padova, Italy
⁸ INAF – Osservatorio Astrofisico di Catania, via Santa Sofia 78, 95123 Catania, Italy
⁹ Astrophysics, Department of Physics, University of Oxford, Oxford, UK
¹⁰ Dipartimento di Astronomia, Universitá di Bologna, via Ranzani 1, 40127 Bologna, Italy
¹¹ INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
¹² INFN, Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna, Italy
¹³ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
¹⁴ Service d'Astrophysique, CEA Saclay, Batiment 709, 91191 Gif-sur-Yvette Cedex, France
¹⁵ Large Binocular Telescope Observatory, University of Arizona, 933 N Cherry Avenue, 85721-0065 Tucson, Arizona, USA
¹⁶ INAF – Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34131 Trieste, Italy

Received: 8 June 2009
Accepted: 3 February 2010

Abstract

Aims. The Large Binocular Cameras (LBC) are two twin wide field cameras (FOV ~ 23' × 25') mounted at the prime foci of the 8.4 m Large Binocular Telescope (LBT). We performed a weak lensing analysis of the z = 0.288 cluster Abell 611 on g-band data obtained by the blue-optimized LBC in order to estimate the cluster mass.

Methods. Owing to the complexity of the PSF of LBC, we decided to use two different approaches, KSB and shapelets, to measure the shape of background galaxies and to derive the shear signal produced by the cluster. Then we estimated the cluster mass with both aperture densitometry and parametric model fits.

Results. The combination of the large aperture of the telescope and the wide field of view allowed us to map a region well beyond the expected virial radius of the cluster and to get a high surface density for background galaxies (23 galaxies/arcmin²). This made it possible to estimate an accurate mass for Abell 611. We find that the mass within 1.5 Mpc is (8±3)× 10¹⁴  from the aperture mass technique and (5±1)× 10¹⁴  using the model fitting by an NFW mass density profile for both shapelet and KSB methods. This analysis demonstrates that LBC is a powerful instrument for weak gravitational lensing studies.