A Caltech Library Service

Line Emitting Galaxies Beyond a Redshift of 7: An Improved Method for Estimating the Evolving Neutrality of the Intergalactic Medium

Schenker, Matthew A. and Ellis, Richard S. and Konidaris, Nick P. and Stark, Daniel P. (2014) Line Emitting Galaxies Beyond a Redshift of 7: An Improved Method for Estimating the Evolving Neutrality of the Intergalactic Medium. . (Submitted)

PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


The redshift-dependent fraction of color-selected galaxies revealing Lyman alpha emission has become the most valuable constraint on the evolving neutrality of the early intergalactic medium. However, in addition to resonant scattering by neutral gas, the visibility of Lyman alpha is also dependent on the intrinsic properties of the host galaxy, including its stellar population, dust content and the nature of outflowing gas. Taking advantage of significant progress we have made in determining the line emitting properties of z≃4−6 galaxies, we propose an improved method, based on using the measured slopes of the rest-frame ultraviolet continua of galaxies, to interpret the growing body of near-infrared spectra of z>7 galaxies in order to take into account these host galaxy dependencies. In a first application of our new method, we demonstrate its potential via a new spectroscopic survey of 7<z<8 galaxies undertaken with the Keck MOSFIRE spectrograph. Together with earlier published data our data provides improved estimates of the evolving visibility of Lyman alpha, particularly at redshift z≃8. As a byproduct, we also present a new line emitting galaxy at a redshift z=7.62 which supersedes an earlier redshift record. We discuss the improving constraints on the evolving neutral fraction over 6<z<8 and the implications for cosmic reionization.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Ellis, Richard S.0000-0001-7782-7071
Konidaris, Nick P.0000-0003-1905-2815
Additional Information:We thank Chuck Steidel and Ian McLain for their sterling efforts in developing the highly successful MOSFIRE instrument. We also wish to recognize and acknowledge the very signicant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Record Number:CaltechAUTHORS:20140505-111931471
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45495
Deposited By: Ruth Sustaita
Deposited On:05 May 2014 20:19
Last Modified:03 Oct 2019 06:31

Repository Staff Only: item control page