Spectroscopic observation of Ly$\alpha$ emitters at z~7.7 and implications on re-ionization

Abstract

We present spectroscopic follow-up observations on two bright Ly$\alpha$ emitter (LAE) candidates originally found by Krug et al. (2012) at a redshift of z~7.7 using the Multi-Object Spectrometer for Infra-Red Exploration (MOSFIRE) at Keck. We rule out any line emission at the >5$\sigma$ level for both objects, putting on solid ground a previous null result for one of the objects. The limits inferred from the non-detections rule out the previous claim of no or even reversed evolution between 5.7 < z < 7.7 in the Ly$\alpha$ luminosity function (LF) and suggest a drop in the Ly$\alpha$ luminosity function consistent with that seen in Lyman Break galaxy (LBG) samples. We model the redshift evolution of the LAE LF using the LBG UV continuum LF and the observed rest-frame equivalent width distribution. From the comparison of our empirical model with the observed LAE distribution, we estimate lower limits of the neutral hydrogen fraction to be 50-70% at z~7.7. Together with this, we find a strong evolution in the Ly$\alpha$ optical depth characterized by (1+z)^(2.2 $\pm$ 0.5) beyond z=6 indicative of a strong evolution of the IGM. Finally, we extrapolate the LAE LF to z~9 using our model and show that it is unlikely that large area surveys like UltraVISTA or Euclid pick up LAEs at this redshift assuming the current depths and area.

11 pages, 6 figures, 2 tables, Accepted for publication in ApJ (minor changes due to referee's comments)

References in corpus (16)

• The Cosmic Evolution Survey (COSMOS) -- Overview
• A luminous quasar at a redshift of z = 7.085
• UltraVISTA: a new ultra-deep near-infrared survey in COSMOS
• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• The Subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of Lya Emitters from z=3.1 to 5.7 in the 1 deg^2 Field: Luminosity Functions and AGN
• The End of the Reionization Epoch Probed by Ly-alpha Emitters at z=6.5 in the Subaru Deep Field
• Ly-alpha Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field South
• A galaxy at a redshift z = 6.96
• SN 2005ap: A Most Brilliant Explosion
• Studying Reionization with Ly-alpha Emitters
• Spectroscopy of z ~ 7 candidate galaxies: Using Lyman-alpha to constrain the neutral fraction of hydrogen in the high-redshift universe
• On the variability of quasars: a link between Eddington ratio and optical variability?
• Luminosity Functions of Lyman Alpha Emitting Galaxies and Cosmic Reionization of Hydrogen
• Lyman Alpha Emitters at Redshift 5.7 in the COSMOS Field
• Evolution in the Escape Fraction of Ionizing Photons and the Decline in Strong Lya Emission from z>6 Galaxies
• A 10 deg${}^2$ Lyman-$\alpha$ survey at z=8.8 with spectroscopic follow-up: strong constraints on the LF and implications for other surveys

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