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VLT spectroscopy of galaxies lensed by the AC 114 cluster: Implications for the mass model and the study of low-luminosity galaxies at high-redshift

Campusano, L. E. and Pellò, R. and Kneib, J.-P. and Le Borgne, J.-F. and Fort, B. and Ellis, R. and Mellier, Y. and Smail, I. (2001) VLT spectroscopy of galaxies lensed by the AC 114 cluster: Implications for the mass model and the study of low-luminosity galaxies at high-redshift. Astronomy & Astrophysics, 378 (2). pp. 394-407. ISSN 0004-6361.

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We present the first results of a spectroscopic survey of faint lensed galaxies in the core of the galaxy cluster AC 114 (z = 0.312) obtained from observations with the FORS1 spectrograph mounted on the VLT-Antu (Unit Telescope 1). The galaxies were chosen according to both lensing and photometric redshift criteria in areas close to the high-z critical lines predicted by the gravitational lens model of Natarajan et al. (NKSE, 1998) for this cluster. All the target galaxies are found to correspond to background galaxies with redshift values in the [0.7, 3.5] interval. Our spectroscopic observations confirm the predicted lensing redshifts for 3 of the multiply-imaged galaxies, and together with predictions of the NKSE model led to the discovery of a new 5-image configuration at redshift z = 3.347. A revised NKS model, compatible with the redshift of this new multiple-image system, was generated and employed to calculate the gravitational amplifications of all the observed galaxies. The galaxies corresponding to the multiple-image systems are found to be intrinsically fainter, between 0.5 and 1.5 magnitudes, than the limiting magnitudes of existing blank field studies. When all the observed background galaxies are considered, the resulting intrinsic absolute magnitudes range from M_B ~ -22 to -19, with a median value of -20.5. Therefore, a large gain in sensitivity towards low luminosity high-z objects can actually be obtained, in agreement with theoretical expectations. This method can be used advantageously to probe the high redshift Universe and, in particular, its application to an ensemble of massive cluster cores could constraint the faint end of luminosity function of high redshift galaxies.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kneib, J.-P.0000-0002-4616-4989
Ellis, R.0000-0001-7782-7071
Smail, I.0000-0003-3037-257X
Alternate Title:VLT Spectroscopy of Galaxies Lensed by Abell AC114: Implication for the Mass Model and the Study of Low-Luminosity Galaxies at High-Redshift
Additional Information:© 2001 ESO. Received: 24 April 2001. Accepted: 14 August 2001. We are grateful to M. Bolzonella, G. Bruzual, M. Dantel-Fort, G. Mathez and D. Schaerer for useful discussions on this particular program. We would like to thank W. J. Couch for providing his deep B image of AC114, and C. Leitherer for allowing the use of the NGC 4214 spectrum. L.E.C. was partially supported by FONDECYT grant 1970735. Part of this work was supported by the French Centre National de la Recherche Scientifique, by the French Programme National de Cosmologie (PNC), and the TMR Lensnet ERBFMRXCT97-0172 ( and the ECOS SUD Program. Based on observations collected at the European Southern Observatory, Chile (ESO P64.O-0439), and with the NASA/ESA Hubble Space Telescope, which is operated by STScI for the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.
Funding AgencyGrant Number
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1970735
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Programme National de Cosmologie (PNC)UNSPECIFIED
TMR LensnetERBFMRXCT97-0172
Subject Keywords:cosmology: observations - galaxies: clusters: individual (AC114) - galaxies: fundamental parameters - gravitational lensing - galaxies: redshifts - general
Issue or Number:2
Record Number:CaltechAUTHORS:20180226-081547388
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Official Citation:VLT spectroscopy of galaxies lensed by the AC 114 cluster: - Implications for the mass model and the study of low-luminosity galaxies at high-redshift L. E. Campusano, R. Pelló, J.-P. Kneib, J.-F. Le Borgne, B. Fort, R. Ellis, Y. Mellier and I. Smail A&A, 378 2 (2001) 394-407 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84947
Deposited By: Ruth Sustaita
Deposited On:26 Feb 2018 19:32
Last Modified:17 Dec 2019 23:40

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