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Galaxies Under the Cosmic Microscope: A GMOS Study of the Lensed Disk-Galaxy #289 in A2218

A. M. Swinbank·J. Smith·R. G. Bower·A. Bunker·I. Smail·R. S. Ellis·Graham P. Smith·J. P. Kneib·M. Sullivan·J. Allington-Smith
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Abstract

In this letter, we exploit the gravitational potential of the rich cluster A2218 as a magnifying glass. We demonstrate that the magnification due to the cluster allows us to observe distant background galaxies at a comparable level of detail to galaxies at z~0.1. Using the GMOS Integral Field Unit on Gemini North we observed the spatially-resolved [OII](3727) emission line spectrum for a lensed disk-galaxy at z=1.034. Using a detailed model for the cluster mass distribution, we are able to correct for the lensing by the cluster and reconstruct the source morphology. We find that the overall magnification is a factor of 4.92 +/- 0.15, and the rest-frame absolute I-band magnitude is M_{I}^{rest} = -22.4 +/- 0.2, where the error bars include conservative estimates of the uncertainty in the source-plane reconstruction. The inclination-corrected circular velocity is 206 +/- 18km/s. The galaxy lies very close to the mean Tully-Fisher relation of present-day spirals. Although our results are based on a single object, they demonstrate that gravitational lensing can be viably used to make detailed studies of the evolution of the structure of distant field galaxies.

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A. M. Swinbank, J. Smith, R. G. Bower, A. Bunker, I. Smail, R. S. Ellis, Graham P. Smith, J. P. Kneib, M. Sullivan, J. Allington-Smith. 2003-07-30. Galaxies Under the Cosmic Microscope: A GMOS Study of the Lensed Disk-Galaxy #289 in A2218. https://doi.org/10.1086/378787

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