Please use this identifier to cite or link to this item:
https://www.um.edu.mt/library/oar/handle/123456789/87318
Title: | Spectroscopy of z ∼ 7 candidate galaxies: using Lyman α to constrain the neutral fraction of hydrogen in the high-redshift universe |
Authors: | Caruana, Joseph Bunker, Andrew J. Wilkins, Stephen M. Stanway, Elizabeth R. Lorenzoni, Silvio Jarvis, Matt J. Ebert, Holly |
Keywords: | Galaxies Astrophysics Galaxies -- Evolution Galaxies -- Observations Red shift -- Observations Galaxies -- Formation Cosmology Cosmology -- Observations Starbursts |
Issue Date: | 2014 |
Publisher: | Royal Astronomical Society |
Citation: | Caruana, J., Bunker, A. J., Wilkins, S. M., Stanway, E. R., Lorenzoni, S., Jarvis, M. J., & Ebert, H. (2014). Spectroscopy of z∼ 7 candidate galaxies: using Lyman α to constrain the neutral fraction of hydrogen in the high-redshift universe. Monthly Notices of the Royal Astronomical Society, 443(4), 2831-2842. |
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 broad-band magnitudes are used to constrain the rest-frame equivalent widths for this line emission. We analyse our FORS2 observations in combination with our previous GNIRS and XSHOOTER observations, and suggest that a simple model where the fraction of high rest-frame equivalent width emitters follows the trend seen at z = 3-6.5 is inconsistent with our non-detections at z ∼ 7.8 at the 96 per cent confidence level. This may indicate that a significant neutral H I fraction in the intergalactic medium suppresses Lyman α, with an estimated neutral fraction χHI∼0.5, in agreement with other estimates. |
URI: | https://www.um.edu.mt/library/oar/handle/123456789/87318 |
Appears in Collections: | Scholarly Works - FacSciPhy |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
stu1341.pdf Restricted Access | 1.68 MB | Adobe PDF | View/Open Request a copy |
Items in OAR@UM are protected by copyright, with all rights reserved, unless otherwise indicated.