PI: Gabor Worseck, UCO/Lick Observatory, UC Santa Cruz, email@example.com
Address: Department of Astronomy and Astrophysics, 1156 High Street, Santa Cruz, CA 95064, USA
CoI: Joseph Hennawi, MPIA Heidelberg, Germany
CoI: Aldo Dall'Aglio, AIP Potsdam, Germany
CoI: Matthew McQuinn, UC Berkeley
Title: A dedicated quasar survey to identify the sources of \ionHe2 reionization
Abstract: We will exploit the large field of view of the MOSAIC camera on the KPNO 4-m telescope to conduct a census of foreground QSOs in the fields of six rare far UV transmitting QSO sightlines useful for studying \ionHe2 reionization. Deep multicolor imaging will allow us to photometrically select the faint foreground QSOs responsible for doubly ionizing helium at z~ 3. By directly linking features in (background) \ionHe2 transmission spectra with the (foreground) ionizing sources, we will answer fundamental questions about reionization, QSOs, and the physical state of the IGM. Our background \ionHe2 QSOs have just recently been confirmed to display \ionHe2 absorption along their sightlines. Science-grade HST/COS spectra of them either exist already, or they are scheduled to be taken in May 2011. A dedicated QSO survey in the vicinity of these rare sightlines is required to fully interpret the strongly fluctuating \ionHe2 absorption near the \ionHe2 reionization epoch. Our observations will assess the morphology of \ionHe2 reionization and constrain numerical models thereof. Directly identifying the QSOs that completed helium reionization is the obvious next step in \ionHe2 reionization studies in the HST/COS era.
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