X-shooter Observations of the Gravitational Lens System CASSOWARY 5
Abstract
We confirm an eighth gravitational lens system in the CASSOWARY catalogue. Exploratory observations with the X-shooter spectrograph on the VLT show the system CSWA5 to consist of at least three images of a blue star-forming galaxy at z = 1.0686, lensed by an apparent foreground group of red galaxies one of which is at z = 0.3877. The lensed galaxy exhibits a rich spectrum with broad interstellar absorption lines and a wealth of nebular emission lines. Preliminary analysis of these features shows the galaxy to be young, with an age of 25-50 Myr. With a star-formation rate of approximately 20 solar masses/yr, the galaxy has already assembled a stellar mass of 3 x 10^9 solar masses and reached half-solar metallicity. Its blue spectral energy distribution and Balmer line ratios suggest negligible internal dust extinction. A more in-depth analysis of the properties of this system is currently hampered by the lack of a viable lensing model. However, it is already clear that CSWA5 shares many of its physical characteristics with the general population of UV-selected galaxies at redshifts z = 1-3, motivating further study of both the source and the foreground mass concentration responsible for the gravitational lensing.
Keywords
Cite
@article{arxiv.1004.3546,
title = {X-shooter Observations of the Gravitational Lens System CASSOWARY 5},
author = {Lise Christensen and Sandro D'Odorico and Max Pettini and Vasily Belokurov and N. Wyn Evans and Melinda Kellogg and Joel Vernet},
journal= {arXiv preprint arXiv:1004.3546},
year = {2010}
}
Comments
12 pages; Accepted for publication in MNRAS