NOAO >   Observing Info >   Approved Programs >   2009B-0174

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Proposal Information for 2009B-0174


PI: Ross Fadely, Rutgers University, fadely@physics.rutgers.edu
Address: Physics Department, 136 Frelinghuysen Rd., Piscataway, 08854 08854, US

CoI: Charles R. Keeton, Rutgers University

Title: Testing CDM with Substructure Gravitational Lensing

Abstract: We propose Gemini K and L' band imaging of 14 gravitationally lensed quasars to investigate the presence of cold dark matter (CDM) substructure. N-body simulations predict that galaxy and cluster halos contain a myriad of subhalos, many of which may be dark. Due to lensing on micro- and milli-arcsecond scales, flux ratios across different wavelengths (corresponding to different source sizes) are sensitive to substructure in halos. An on-going investigation of data taken at Gemini North in semester 2008B has revealed that new infrared measurements, in conjunction with existing optical and radio data, can powerfully constrain the existence and nature of subhalo perturbers to lensing potentials. Our proposed Gemini observations will dramatically improve the existing sample of millilensing measurements of substructure, allowing new statistical tests of CDM predictions.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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