NOAO >   Observing Info >   Approved Programs >   2012A-0268

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Proposal Information for 2012A-0268


PI: Robert Bussmann, Harvard-Smithsonian Center for Astrophysics, rbussmann@cfa.harvard.edu
Address: 60 Garden Street, Cambridge, MA 02138, USA

CoI: Aprajita Verma, Oxford, UK
CoI: Dan Smith, University of Nottingham
CoI: Mark Swinbank, Durham
CoI: Loretta Dunne, Nottingham, UK
CoI: Mattia Negrello, Open University
CoI: Simon Dye, Cardiff, UK
CoI: Steve Eales, Cardiff, UK
CoI: Ros Hopwood, Open University
CoI: Rob Ivison, Edinburgh, UK
CoI: Matt Jarvis, University of Hertfordshire, UK
CoI: Steve Maddox, Nottingham, UK
CoI: Emma Rigby, Nottingham, UK

Title: Longslit Spectroscopy of Lensing Galaxies Discovered in the Herschel-ATLAS

Abstract: We propose optical spectroscopic observations of a sample of 12 strong-lensing galaxies discovered in the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) that currently lack optical spectroscopic follow-up. Redshifts to the background lensed galaxy are available for all 12 systems and high-spatial resolution sub-millimeter observations which allow detailed gravitational lens models to be constructed are available for 5/12 (with the remaining 7 proposed for 2012A sub-millimeter observations). These models provide both a measure of the magnification of the background source as well as the Einstein radius of the foreground lens. The Einstein radius can in turn be used to determine the mass of the lens, but only if a precise distance to the lens is known. Previous experience with Gemini GMOS-S has established that spectral features can be identified in the lensing galaxies out to at least z=0.6. We propose a series of longslit observations of all twelve lensing galaxies to determine their redshifts and velocity dispersions. The velocity dispersions can be compared directly with the masses derived from the lens modeling as well as stellar masses obtained with stellar population synthesis modeling to test the relationship of dark and light matter in galaxies out to z=0.6 and possibly beyond.


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NOAO >   Observing Info >   Approved Programs >   2012A-0268

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