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Intensity Mapping of Lyman-alpha Emission During the Epoch of Reionization

Silva, Marta B. and Santos, Mario G. and Gong, Yan and Cooray, Asantha and Bock, James (2013) Intensity Mapping of Lyman-alpha Emission During the Epoch of Reionization. Astrophysical Journal, 763 (2). Art. No. 132. ISSN 0004-637X. doi:10.1088/0004-637X/763/2/132.

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We calculate the absolute intensity and anisotropies of the Lyα radiation field present during the epoch of reionization. We consider emission from both galaxies and the intergalactic medium (IGM) and take into account the main contributions to the production of Lyα photons: recombinations, collisions, continuum emission from galaxies, and scattering of Lyn photons in the IGM. We find that the emission from individual galaxies dominates over the IGM with a total Lyα intensity (times frequency) of about (1.43-3.57) × 10^(–8) erg s^(–1) cm^(–2) sr^(–1) at a redshift of 7. This intensity level is low, so it is unlikely that the Lyα background during reionization can be established by an experiment aiming at an absolute background light measurement. Instead, we consider Lyα intensity mapping with the aim of measuring the anisotropy power spectrum that has rms fluctuations at the level of 1 × 10^(–1)6 [erg s^(–1) cm^(–2) sr^(–1)]^2 at a few Mpc scales. These anisotropies could be measured with a spectrometer at near-IR wavelengths from 0.9 to 1.4 μm with fields in the order of 0.5 to 1 deg^2. We recommend that existing ground-based programs using narrowband filters also pursue intensity fluctuations to study statistics on the spatial distribution of faint Lyα emitters. We also discuss the cross-correlation signal with 21 cm experiments that probe H I in the IGM during reionization. A dedicated sub-orbital or space-based Lyα intensity mapping experiment could provide a viable complimentary approach to probe reionization, when compared to 21 cm experiments, and is likely within experimental reach.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Silva, Marta B.0000-0003-0209-4816
Santos, Mario G.0000-0003-3892-3073
Cooray, Asantha0000-0002-3892-0190
Bock, James0000-0002-5710-5212
Additional Information:© 2013 The American Astronomical Society. Received 2012 May 10. Accepted 2012 November 30. Published 2013 January 17. This work was supported by FCT-Portugal with the grant SFRH/BD/51373/2011 for M.B.S. and under grant PTDC/FIS/100170/2008 for M.B.S. and M.G.S. A.C. and Y.G. acknowledge support from NSF CAREER AST-0645427 and NASA NNX10AD42G at UCI. M.B.S. was a long-term Visiting Student at UCI, supported by NSF CAREER AST-0645427, when this work was initiated, and she thanks the Department of Physics and Astronomy at UCI for hospitality during her stay.
Group:Keck Institute for Space Studies
Funding AgencyGrant Number
Fundação para a Ciência e a Tecnologia (FCT)SFRH/BD/51373/2011
Fundação para a Ciência e a Tecnologia (FCT)PTDC/FIS/100170/2008
Keck Institute for Space Studies (KISS)UNSPECIFIED
Subject Keywords:cosmology: theory; diffuse radiation; large-scale structure of universe
Issue or Number:2
Record Number:CaltechAUTHORS:20160224-150511943
Persistent URL:
Official Citation:Marta B. Silva et al 2013 ApJ 763 132
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:64745
Deposited By: Colette Connor
Deposited On:25 Feb 2016 00:22
Last Modified:10 Nov 2021 23:34

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