TY - JOUR
T1 - Spectral variations of Lyman alpha emission within strongly lensed sources observed with MUSE
AU - Claeyssens, A.
AU - Richard, J.
AU - Blaizot, J.
AU - Garel, T.
AU - Leclercq, F.
AU - Patricio, V.
AU - Verhamme, A.
AU - Wisotzki, L.
AU - Bacon, R.
AU - Carton, D.
AU - Clement, B.
AU - Herenz, E. C.
AU - Marino, R. A.
AU - Muzahid, S.
AU - Saust, R.
AU - Schaye, J.
PY - 2019/11/11
Y1 - 2019/11/11
N2 - 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.
AB - 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.
KW - gravitational lensing: strong
KW - galaxies: high-redshift
KW - ultraviolet: galaxies
U2 - 10.1093/mnras/stz2492
DO - 10.1093/mnras/stz2492
M3 - Journal article
SN - 0035-8711
VL - 489
SP - 5022
EP - 5029
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
IS - 4
ER -