%0 Journal Article %T A double-peaked Lyman-α emitter with a stronger blue peak multiply imaged by the galaxy cluster RXC J0018.5+1626 %+ Institut d'Astrophysique de Paris (IAP) %A Furtak, Lukas J. %A Plat, Adèle %A Zitrin, Adi %A Topping, Micheal W. %A Stark, Daniel P. %A Strait, Victoria %A Charlot, Stéphane %A Coe, Dan %A Andrade-Santos, Felipe %A Bradač, Maruša %A Bradley, Larry %A Lemaux, Brian C. %A Sharon, Keren %< avec comité de lecture %@ 0035-8711 %J Monthly Notices of the Royal Astronomical Society %I Oxford University Press (OUP): Policy P - Oxford Open Option A %8 2022 %D 2022 %Z 2204.09668 %Z 2022MNRAS.tmp.2066F %R 10.1093/mnras/stac2169 %K gravitational lensing: strong %K dark ages %K reionization %K first stars %K galaxies: star formation %K galaxies: evolution %K ISM: lines and bands %K galaxies: clusters: individual: RXC J0018.5+1626 %K Astrophysics - Astrophysics of Galaxies %Z Sciences of the Universe [physics]Journal articles %X We report the discovery of a double-peaked Lyman-α (Lyα) emitter (LAE) at z = 3.2177 ± 0.0001 in VLT/MUSE data. The galaxy is strongly lensed by the galaxy cluster RXC J0018.5+1626 recently observed in the RELICS survey, and the double-peaked Lyα emission is clearly detected in the two counter images in the MUSE field-of-view. We measure a relatively high Lyα rest-frame equivalent width (EW) of EWLyα, 0 = (63 ± 2) Å. Additional spectroscopy with Gemini/GNIRS in the near-infrared (NIR) allows us to measure the Hβ, [O III]λ4959Å and [O III]λ5007Å emission lines, which show moderate rest-frame EWs of the order of a few ~10 - 100 Å, an [O III]λ5007Å/Hβ ratio of 4.8 ± 0.7, and a lower limit on the [O III]/[O II] ratio of >9.3. The galaxy has very blue UV-continuum slopes of βFUV = -2.23 ± 0.06 and βNUV = -3.0 ± 0.2, and is magnified by factors μ ~ 7 - 10 in each of the two images, thus enabling a view into a low-mass (M ≃ 107.5 M) high-redshift galaxy analog. Notably, the blue peak of the Lyα profile is significantly stronger than the red peak, which suggests an inflow of matter and possibly very low H I column densities in its circumgalactic gas. To the best of our knowledge, this is the first detection of such a Lyα profile. Combined with the high lensing magnification and image multiplicity, these properties make this galaxy a prime candidate for follow-up observations to search for LyC emission and constrain the LyC photon escape fraction. %G English %2 https://insu.hal.science/insu-03748229/document %2 https://insu.hal.science/insu-03748229/file/stac2169.pdf %L insu-03748229 %U https://insu.hal.science/insu-03748229 %~ INSU %~ CNRS %~ IAP %~ SORBONNE-UNIVERSITE %~ SORBONNE-UNIV %~ SU-SCIENCES %~ SU-TI %~ ALLIANCE-SU