Following our previous spectroscopic observations of $z>7$ galaxies with
Gemini/GNIRS and VLT/XSHOOTER, which targeted a total of 8 objects, we present
here our results from a deeper and larger VLT/FORS2 spectroscopic sample of
Wide Field Camera 3 selected $z>7$ candidate galaxies. With our FORS2 setup we
cover the 737-1070nm wavelength range, enabling a search for Lyman-$\alpha$ in
the redshift range spanning 5.06 - 7.80. We target 22 $z$-band dropouts and
find no evidence of Lyman-$\alpha$ emission. The upper limits on Lyman-$\alpha$
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
$z\sim7.8$ at the 96\% confidence level. This may indicate that a significant
neutral HI fraction in the intergalactic medium suppresses Lyman-$\alpha$, with
an estimated neutral fraction $\chi_HI\sim0.5$, in agreement with other
estimates.
Beschreibung
[1311.0057] Spectroscopy of z ~ 7 candidate galaxies: Using Lyman-alpha to constrain the neutral fraction of hydrogen in the high-redshift universe
%0 Generic
%1 caruana2013spectroscopy
%A Caruana, Joseph
%A Bunker, Andrew J.
%A Wilkins, Stephen M.
%A Stanway, Elizabeth R.
%A Lorenzoni, Silvio
%A Jarvis, Matt J.
%A Elbert, Holly
%D 2013
%K igm lya neutral transfer
%T Spectroscopy of z ~ 7 candidate galaxies: Using Lyman-alpha to constrain
the neutral fraction of hydrogen in the high-redshift universe
%U http://arxiv.org/abs/1311.0057
%X Following our previous spectroscopic observations of $z>7$ galaxies with
Gemini/GNIRS and VLT/XSHOOTER, which targeted a total of 8 objects, we present
here our results from a deeper and larger VLT/FORS2 spectroscopic sample of
Wide Field Camera 3 selected $z>7$ candidate galaxies. With our FORS2 setup we
cover the 737-1070nm wavelength range, enabling a search for Lyman-$\alpha$ in
the redshift range spanning 5.06 - 7.80. We target 22 $z$-band dropouts and
find no evidence of Lyman-$\alpha$ emission. The upper limits on Lyman-$\alpha$
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
$z\sim7.8$ at the 96\% confidence level. This may indicate that a significant
neutral HI fraction in the intergalactic medium suppresses Lyman-$\alpha$, with
an estimated neutral fraction $\chi_HI\sim0.5$, in agreement with other
estimates.
@misc{caruana2013spectroscopy,
abstract = {Following our previous spectroscopic observations of $z>7$ galaxies with
Gemini/GNIRS and VLT/XSHOOTER, which targeted a total of 8 objects, we present
here our results from a deeper and larger VLT/FORS2 spectroscopic sample of
Wide Field Camera 3 selected $z>7$ candidate galaxies. With our FORS2 setup we
cover the 737-1070nm wavelength range, enabling a search for Lyman-$\alpha$ in
the redshift range spanning 5.06 - 7.80. We target 22 $z$-band dropouts and
find no evidence of Lyman-$\alpha$ emission. The upper limits on Lyman-$\alpha$
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
$z\sim7.8$ at the 96\% confidence level. This may indicate that a significant
neutral HI fraction in the intergalactic medium suppresses Lyman-$\alpha$, with
an estimated neutral fraction $\chi_{HI}\sim0.5$, in agreement with other
estimates.},
added-at = {2013-11-05T19:56:25.000+0100},
author = {Caruana, Joseph and Bunker, Andrew J. and Wilkins, Stephen M. and Stanway, Elizabeth R. and Lorenzoni, Silvio and Jarvis, Matt J. and Elbert, Holly},
biburl = {https://www.bibsonomy.org/bibtex/2532d63aeedce701444ab8c063acc41a7/miki},
description = {[1311.0057] Spectroscopy of z ~ 7 candidate galaxies: Using Lyman-alpha to constrain the neutral fraction of hydrogen in the high-redshift universe},
interhash = {67c4b5c5c562ac2933bcd8cd39d31039},
intrahash = {532d63aeedce701444ab8c063acc41a7},
keywords = {igm lya neutral transfer},
note = {cite arxiv:1311.0057Comment: submitted to MNRAS},
timestamp = {2013-11-05T19:56:25.000+0100},
title = {Spectroscopy of z ~ 7 candidate galaxies: Using Lyman-alpha to constrain
the neutral fraction of hydrogen in the high-redshift universe},
url = {http://arxiv.org/abs/1311.0057},
year = 2013
}