Spectroscopy of z 7 candidate galaxies : using Lyman to constrain the neutral fraction of hydrogen in the high-redshift universe

Caruana, J.
Bunker, A. J.
Wilkins, S. M.
Stanway, Elizabeth R.
Lorenzoni, S.
Jarvis, M. J.
Ebert, H.

Publication date

October 2014

DOI

10.1093/mnras/stu1341

Publisher

Oxford University Press (OUP)

Abstract

Following our previous spectroscopic observations of z > 7 galaxies with Gemini/Gemini Near Infra-Red Spectrograph (GNIRS) and Very Large Telescope (VLT)/XSHOOTER, which targeted a total of eight objects, we present here our results from a deeper and larger VLT/FOcal Reducer and Spectrograph (FORS2) spectroscopic sample of Wide Field Camera 3 selected z > 7 candidate galaxies. With our FORS2 setup we cover the 737–1070 nm wavelength range, enabling a search for Lyman α in the redshift range spanning 5.06–7.80. We target 22 z-band dropouts and find no evidence of Lyman α emission, with the exception of a tentative detection (<5σ, which is our adopted criterion for a secure detection) for one object. The upper limits on Lyman α flux and the b...