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Spectral variations of Lyman α emission within strongly lensed sources observed with MUSE

Abstract : We present an analysis of H I Lyman α emission in deep VLT/MUSE observations of two highly magnified and extended galaxies at z=3.5 and 4.03, including a newly discovered, almost complete Einstein ring. While these Lyman α haloes are intrinsically similar to the ones typically seen in other MUSE deep fields, the benefits of gravitational lensing allow us to construct exceptionally detailed maps of Lyman α line properties at sub-kpc scales. By combining all multiple images, we are able to observe complex structures in the Lyman α emission and uncover small (∼120 km s-1 in Lyman α peak shift), but significant at > 4 σ, systematic variations in the shape of the Lyman α line profile within each halo. Indeed, we observe a global trend for the line peak shift to become redder at large radii, together with a strong correlation between the peak wavelength and line width. This systematic intrahalo variation is markedly similar to the object-to-object variations obtained from the integrated properties of recent large samples. Regions of high surface brightness correspond to relatively small line shifts, which could indicate that Lyman α emission escapes preferentially from regions where the line profile has been less severely affected by scattering of Lyman α photons.
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Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Friday, July 1, 2022 - 1:35:50 PM
Last modification on : Saturday, September 24, 2022 - 12:02:05 PM

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A. Claeyssens, J. Richard, J. Blaizot, T. Garel, F. Leclercq, et al.. Spectral variations of Lyman α emission within strongly lensed sources observed with MUSE. Monthly Notices of the Royal Astronomical Society, 2019, 489, pp.5022-5029. ⟨10.1093/mnras/stz2492⟩. ⟨insu-03711410⟩



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