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Implications of $z \sim 6$ Quasar Proximity Zones for the Epoch of Reionization and Quasar Lifetimes by Eilers, Anna-Christina; Davies, Frederick B.; Hennawi, Joseph F.; Prochaska, J. Xavier; Lukić, Zarija; Mazzucchelli, Chiara is a scholarly article available to read on EtoBox.

What is Implications of $z \sim 6$ Quasar Proximity Zones for the Epoch of Reionization and Quasar Lifetimes about?

We study quasar proximity zones in the redshift range $5.77 \leq z \leq 6.54$ by homogeneously analyzing $34$ medium resolution spectra, encompassing both archival and newly obtained data, and exploiting recently updated systemic redshift and magnitude measurements. Whereas previous studies found strong evolution of proximity zone sizes with redshift, and argued that this provides evidence for a rapidly evolving intergalactic medium (IGM) neutral fraction during reionization, we measure a much shallower trend $\propto(1+z)^{-1.44}$. We compare our measured proximity zone sizes to predictions from hydrodynamical simulations post-processed with one-dimensional radiative transfer, and find good agreement between observations and theory irrespective of the ionization state of the ambient IGM. This insensitivity to IGM ionization state has been previously noted, and results from the fact that the definition of proximity zone size as the first drop of the smoothed quasar spectrum below the $10\%$ flux transmission level probes locations where the ionizing radiation from the quasar is an order of magnitude larger than the expected ultraviolet ionizing background that sets the neutral frac

Author

Eilers, Anna-Christina; Davies, Frederick B.; Hennawi, Joseph F.; Prochaska, J. Xavier; Lukić, Zarija; Mazzucchelli, Chiara

Published

2017

Language

EN