TY - JOUR
T1 - A double-peaked Lyman- αemitter with a stronger blue peak multiply imaged by the galaxy cluster RXC J0018.5 + 1626
AU - Furtak, Lukas J.
AU - Plat, Adèle
AU - Zitrin, Adi
AU - Topping, Micheal W.
AU - Stark, Daniel P.
AU - Strait, Victoria
AU - Charlot, Stéphane
AU - Coe, Dan
AU - Andrade-Santo, Felipe
AU - Bradač, Maruša
AU - Bradley, Larry
AU - Lemaux, Brian C.
AU - Sharon, Keren
N1 - Publisher Copyright:
© 2022 Oxford University Press. All rights reserved.
PY - 2022
Y1 - 2022
N2 - We report the discovery of a double-peaked Lyman-α(Ly α) 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 Ly αemission is clearly detected in the two counter images in the MUSE field of view. We measure a relatively high Ly αrest-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 H β, [O III ] λ4959 Å, and [O III ] λ5007 Åemission lines, which show moderate rest-frame EWs of the order of a few ~10-100 Å, an [O III ] λ5007 Å/H βratio 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∗≃ 107.5M⊙) high-redshift galaxy analogue. Notably, the blue peak of the Ly αprofile 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 Ly αprofile. 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.
AB - We report the discovery of a double-peaked Lyman-α(Ly α) 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 Ly αemission is clearly detected in the two counter images in the MUSE field of view. We measure a relatively high Ly αrest-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 H β, [O III ] λ4959 Å, and [O III ] λ5007 Åemission lines, which show moderate rest-frame EWs of the order of a few ~10-100 Å, an [O III ] λ5007 Å/H βratio 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∗≃ 107.5M⊙) high-redshift galaxy analogue. Notably, the blue peak of the Ly αprofile 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 Ly αprofile. 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.
KW - ISM: lines and bands
KW - dark ages, reionization, first stars
KW - galaxies: clusters: individual: RXC J0018.5 + 1626
KW - galaxies: evolution
KW - galaxies: star formation
KW - gravitational lensing: strong
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U2 - 10.1093/mnras/stac2169
DO - 10.1093/mnras/stac2169
M3 - Article
AN - SCOPUS:85140410642
SN - 0035-8711
VL - 516
SP - 1373
EP - 1385
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -