NOAO >   Observing Info >   Approved Programs >   2003B-0184

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Proposal Information for 2003B-0184


PI: Paul Schechter, Massachusetts Institute of Technology, schech@achernar.mit.edu
Address: Physics Department, 77 Massachusetts Avenue, Cambridge, MA 02138, USA

Title: Anomalous flux ratios in two quadruply imaged quasars: millilensing or micro?

Abstract: We propose to observe two quadruply imaged quasars, PG1115+080 and SDSS0924+0219, using the GMOS IFU to measure the emission line and continuum flux ratios for the closest pairs of images, with separations of 0\farcs48 and 0\farcs64. Micro- and milli-lensing by stars and dark matter subhalos, respectively, are the leading explanations for the anomalous flux ratios observed in these image pairs. If milli-lensing is responsible, the emission line and continuum flux ratios should be the same. Micro-lensing would imply the presence of a substantial amount of smoothly distributed dark matter in the lens. Milli-lensing would imply a signicant mass in unseen dark matter sub-halos.


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NOAO >   Observing Info >   Approved Programs >   2003B-0184

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