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Diffuse Lyα haloes around Lyα emitters at z = 3: do dark matter distributions determine the Lyα spatial extents?

Matsuda, Y. and Yamada, T. and Hayashino, T. and Yamauchi, R. and Nakamura, Y. and Morimoto, N. and Ouchi, M. and Ono, Y. and Umemura, M. and Mori, M. (2012) Diffuse Lyα haloes around Lyα emitters at z = 3: do dark matter distributions determine the Lyα spatial extents? Monthly Notices of the Royal Astronomical Society, 425 (2). pp. 878-883. ISSN 0035-8711. doi:10.1111/j.1365-2966.2012.21143.x.

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Using stacks of Lyα images of 2128 Lyα emitters (LAEs) and 24 proto-cluster UV-selected galaxies (LBGs) at z = 3.1, we examine the surface brightness profiles of Lyα haloes around high-z galaxies as a function of environment and UV luminosity. We find that the slopes of the Lyα radial profiles become flatter as the Mpc-scale LAE surface density increases, but that they are almost independent of the central UV luminosity. The characteristic exponential scalelength of the Lyα haloes appears to be proportional to the square of the LAE surface density ((r_(Lyα) ∝ Σ^2_(LAE)). Including the diffuse, extended Lyα haloes, the rest-frame Lyα equivalent width of the LAEs in the densest regions approaches EW_0 ∼ 200 Å, the maximum value expected for young (<10^7 yr) galaxies. This suggests that Lyα photons formed via shock compression by gas outflows or cooling radiation by gravitational gas inflows may partly contribute to the illumination of Lyα haloes; however, most of their Lyα luminosity can be explained by photoionization by or by scattering of Lyα photons produced from H ii regions in and around the central galaxies. Regardless of the source of Lyα photons, if the Lyα haloes trace the overall gaseous structure, following the dark matter distribution, it is not surprising that the Lyα spatial extent depends more strongly on the surrounding Mpc-scale environment than on the activity of the central galaxies.

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URLURL TypeDescription Paper
Ouchi, M.0000-0002-1049-6658
Additional Information:© 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS. Accepted 2012 March 8. Received 2012 March 8; in original form 2011 November 30. Article first published online: 13 Aug 2012. This work is based on data collected with the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. We thank the anonymous referee for useful comments, which significantly improved the clarity of the paper. We also thank Chuck Steidel and Ian Smail for support and encouragement, and Tom Theuns, John Stott, Joop Schaye, Zheng Zheng, Michael Shull, Brian Siana, Naveen Reddy, Gwen Rudie, Ryan Trainor and Jean-Rene Gauthier for discussions and comments. YM acknowledges support from a JSPS Postdoctoral Fellowship for research abroad and from STFC.
Funding AgencyGrant Number
Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Subject Keywords: galaxies: formation; cosmology: observations; cosmology: early universe
Issue or Number:2
Record Number:CaltechAUTHORS:20121009-113829911
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Official Citation:Matsuda, Y., Yamada, T., Hayashino, T., Yamauchi, R., Nakamura, Y., Morimoto, N., Ouchi, M., Ono, Y., Umemura, M. and Mori, M. (2012), Diffuse Lyα haloes around Lyα emitters at z=3: do dark matter distributions determine the Lyα spatial extents?. Monthly Notices of the Royal Astronomical Society, 425: 878–883. doi: 10.1111/j.1365-2966.2012.21143.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34786
Deposited By: Ruth Sustaita
Deposited On:10 Oct 2012 15:17
Last Modified:09 Nov 2021 23:10

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