Infrared observations of gravitational lensing in Abell 2219 with CIRSI
Abstract
We present the first detection of a gravitational depletion signal at near-infrared wavelengths, based on deep panoramic images of the cluster Abell 2219 (z=0.22) taken with the Cambridge Infrared Survey Instrument (CIRSI) at the prime focus of the 4.2-m William Herschel Telescope. Infrared studies of gravitational depletion offer a number of advantages over similar techniques applied at optical wavelengths, and can provide reliable total masses for intermediate-redshift clusters. Using the maximum-likelihood technique developed by Schneider, King & Erben, we detect the gravitational depletion at the 3σ confidence level. By modelling the mass distribution as a singular isothermal sphere and ignoring the uncertainty in the unlensed number counts, we find an Einstein radius of θ_E ≃ 13.7^(+3.9)_(-4.2) arcsec (66 per cent confidence limit). This corresponds to a projected velocity dispersion of σᵥ∼800 km s⁻¹, in agreement with constraints from strongly lensed features. For a Navarro, Frenk & White mass model, the radial dependence observed indicates a best-fitting halo scalelength of 125h⁻¹ kpc. We investigate the uncertainties arising from the observed fluctuations in the unlensed number counts, and show that clustering is the dominant source of error. We extend the maximum-likelihood method to include the effect of incompleteness, and discuss the prospects of further systematic studies of lensing in the near-infrared band.
Additional Information
© 2000 RAS. Received: 07 June 2000. Accepted: 09 June 2000. Published: 21 October 2000. We thank Peter Schneider, Lindsay King, Andy Taylor and Konrad Kuijken for useful discussions, and Felipe Menanteau for assistance with the GISSEL96 models. The Cambridge Infrared Survey Instrument is available thanks to the generous support of Raymond and Beverly Sackler. MEG acknowledges the support of the Canadian Cambridge Trust and the Worshipful Company of Scientific Instrument Makers. AR was supported by the European TMR Lensing network and by a Wolfson College Fellowship. This research has been conducted under the auspices of the European TMR network 'Gravitational Lensing: New Constraints on Cosmology and the Distribution of Dark Matter' made possible via generous financial support from the European Commission (http://www.ast.cam.ac.uk/IoA/lensnet).Attached Files
Published - 318-2-573.pdf
Accepted Version - 0004161.pdf
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Additional details
- Eprint ID
- 103823
- Resolver ID
- CaltechAUTHORS:20200610-122805723
- Raymond and Beverly Sackler Foundation
- Canadian Cambridge Trust
- Worshipful Company of Scientific Insturment Makers
- TMR Lensnet
- Wolfson College
- European Commission
- Created
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2020-06-10Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field