NOAO >   Observing Info >   Approved Programs >   2012B-0526

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Proposal Information for 2012B-0526


PI: Gabor Worseck, UCO/Lick Observatory, UC Santa Cruz, gworseck@ucolick.org
Address: Department of Astronomy and Astrophysics, 1156 High Street, Santa Cruz, CA 95064, USA

CoI: Joseph F. Hennawi, MPIA Heidelberg, Germany
CoI: J. Xavier Prochaska, UCO/Lick Observatory

Title: Revealing the Proximity Zones of Helium-Reionizing Quasars at \boldmathz~ 3\unboldmath

Abstract: We propose to obtain near-infrared (NIR) spectroscopy of 13 2.7<z<3.9 quasars with detected intergalactic \ionHe2 absorption. These quasars are extremely rare on the sky and have been invaluable to constrain the second epoch of reionization when helium became fully ionized at z~ 3. Each luminous quasar is expected to ionize a \ga4 Mpc region around it, but the growing archive of HST/COS \ionHe2 spectra shows a large variety of \ionHe3 zones with different sizes and evident substructure. The proposed NIR spectroscopy obtained with Palomar/TripleSpec and Gemini/GNIRS will allow us to pin down the redshifts of the background quasars to better than 300 km s^-1 and thus to locate the highly ionized \ionHe3 quasar proximity zones to better than 1 Mpc. With this first statistical sample of well-studied quasar \ionHe3 zones we will be able to answer fundamental questions about reionization, quasars, and the physical state of the intergalactic medium at z~ 3.


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NOAO >   Observing Info >   Approved Programs >   2012B-0526

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