Speaker
Dr
David Syphers
(University of Colorado, Boulder)
Description
The reionization of He II at z~3 was the last major change in the ionization state of the IGM. In addition, the reionization of He II may also aid theoretical understanding of the later stages of hydrogen reionization. In recent years we have dramatically increased the number of He II Gunn-Peterson trough observations. Previously there were only two Gunn-Peterson observations at medium resolution (R>10,000), both with low S/N and one covering only the post-reionization epoch. Such resolution is crucial for gap statistics and other metrics sensitive to the progress of reionization. This year we are tripling the number of such observations to six, which for the first time will allow a statistical understanding of this epoch using higher-resolution techniques. I discuss the first medium-resolution observations of the well-known He II quasar Q0302-003, and preliminary results from a 2013 survey of three newly confirmed He II quasars.
