Gravitational lens magnification by Abell 1689: distortion of the background galaxy luminosity function |
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Authors: | S. Dye A. N. Taylor E. M. Thommes K. Meisenheimer C. Wolf J. A. Peacock |
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Affiliation: | Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ;Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany;Astrophysics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2BW |
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Abstract: | Gravitational lensing magnifies the observed flux of galaxies behind the lens. We use this effect to constrain the total mass in the cluster Abell 1689 by comparing the lensed luminosities of background galaxies with the luminosity function of an undistorted field. Under the assumption that these galaxies are a random sample of luminosity space, this method is not limited by clustering noise. We use photometric redshift information to estimate galaxy distance and intrinsic luminosity. Knowing the redshift distribution of the background population allows us to lift the mass/background degeneracy common to lensing analysis. In this paper we use nine filters observed over 12 h with the Calar Alto 3.5-m telescope to determine the redshifts of 1000 galaxies in the field of Abell 1689. Using a complete sample of 146 background galaxies we measure the cluster mass profile. We find that the total projected mass interior to 0.25 h −1 Mpc is M 2D(<0.25 h −1 Mpc)=(0.48±0.16)×1015 h −1 M⊙, where our error budget includes uncertainties from the photometric redshift determination, the uncertainty in the offset calibration and finite sampling. This result is in good agreement with that found by number-count and shear-based methods and provides a new and independent method to determine cluster masses. |
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Keywords: | gravitational lensing galaxies: clusters: general galaxies: clusters: individual: Abell 1689 cosmology: theory large-scale structure of Universe |
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