%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