Kakiichi, K;
Ellis, RS;
Laporte, N;
Zitrin, A;
Eilers, A-C;
Ryan-Weber, E;
Meyer, RA;
... Bosman, SEI; + view all
(2018)
The Role of Galaxies and AGN in Reionising the IGM - I: Keck Spectroscopy of 5 < z < 7 Galaxies in the QSO Field J1148+5251.
Monthly Notices of the Royal Astronomical Society
, 479
(1)
pp. 43-63.
10.1093/mnras/sty1318.
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Abstract
We introduce a new method for determining the influence of galaxies and active galactic nuclei (AGN) on the intergalactic medium (IGM) at high redshift and illustrate its potential via a first application to the field of the z = 6.42 QSO J1148+5251. Correlating spatial positions Lyman break galaxies (LBGs) with the Lyman alpha forest seen in the spectrum of a background QSO, we provide a statistical measure of the typical escape fraction of Lyman continuum photons. Using Keck DEIMOS spectroscopy to locate 7 colour-selected LBGs in the range 5.3 ≲ z ≲ 6.4 we examine the spatial correlation between this sample and Lyα/Lyβ transmission fluctuations in a Keck ESI spectrum of the QSO. Interpreting the statistical HI proximity effect as arising from faint galaxies clustered around the LBGs, we translate the observed mean Lyα transmitted flux into a constraint on the mean escape fraction ⟨fesc⟩ ≥ 0.08 at z ≃ 6. We also report individual transverse HI proximity effect for a z = 6.177 luminous LBG via a Lyβ transmission spike and two broad Lyα transmission spikes around the z = 5.701 AGN. We discuss the origin of such associations which suggest that while faint galaxies are primarily driving reionisation, luminous galaxies and AGN may provide important contributions to the UV background or thermal fluctuations of the IGM at z ≃ 6. Although a limited sample, our results demonstrate the potential of making progress using this method in resolving one of the most challenging aspects of the contribution of galaxies and AGN to cosmic reionisation.
| Type: | Article |
|---|---|
| Title: | The Role of Galaxies and AGN in Reionising the IGM - I: Keck Spectroscopy of 5 < z < 7 Galaxies in the QSO Field J1148+5251 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/sty1318 |
| Publisher version: | https://doi.org/10.1093/mnras/sty1318 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | galaxies: formation, galaxies: high-redshift, intergalactic medium, quasars: absorption lines, cosmology: observations, dark ages, reionization, first stars |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10048531 |
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