@article{bca62ebcce9f4851a926424795a8a35d,
title = "RelicS: Spectroscopy of gravitationally lensed z = 2 reionization-era analogues and implications for C III] detections at z > 6",
abstract = "Recent observations have revealed the presence of strong C III] emission (EWC III] > 20 {\AA}) in z > 6 galaxies, the origin of which remains unclear. In an effort to understand the nature of these line emitters, we have initiated a survey targeting C III] emission in gravitationally lensed reionization-era analogues identified in Hubble Space Telescope imaging of clusters from the Reionization Lensing Cluster Survey. Here, we report initial results on four galaxies selected to have low stellar masses (2-8 × 107 M☉) and J125-band flux excesses indicative of intense [O III] + H β emission (EW[O III]+H β = 500-2000 {\AA}), similar to what has been observed at z > 6. We detect C III] emission in three of the four sources, with the C III] EW reaching values seen in the reionization era (EWC III] = 17-22 {\AA}) in the two sources with the strongest optical line emission (EW[O III]+H β = 2000 {\AA}). We have obtained a Magellan/FIRE (Folded-port InfraRed Echellette) near-infrared spectrum of the strongest C III] emitter in our sample, revealing gas that is both metal poor and highly ionized. Using photoionization models, we are able to simultaneously reproduce the intense C III] and optical line emission for extremely young (2-3 Myr) and metal-poor (0.06-0.08 Z☉) stellar populations, as would be expected after a substantial upturn in the star formation rate of a low-mass galaxy. The sources in this survey are among the first for which C III] has been used as the primary means of redshift confirmation. We suggest that it should be possible to extend this approach to z > 6 with current facilities, using C III] to measure redshifts of objects with IRAC excesses indicating EW[O III]+H β = 2000 {\AA}, providing a method of spectroscopic confirmation independent of Ly α.",
keywords = "Galaxies: ISM, Galaxies: abundances, Galaxies: dwarf, Galaxies: evolution, Galaxies: formation, Galaxies: high-redshift",
author = "Ramesh Mainali and Stark, {Daniel P.} and Mengtao Tang and Jacopo Chevallard and St{\'e}phane Charlot and Keren Sharon and Dan Coe and Brett Salmon and Bradley, {Larry D.} and Johnson, {Traci L.} and Brenda Frye and Avila, {Roberto J.} and Sara Ogaz and Adi Zitrin and Maru{\v s}a Brada{\v c} and Lemaux, {Brian C.} and Guillaume Mahler and Rachel Paterno-Mahler and Victoria Strait and Felipe Andrade-Santos",
note = "Funding Information: We thank Xinnan Du, Anna Feltre, Taylor Hutchison, Alice Shapley, and Casey Papovich for helpful discussions. DPS acknowledges support from the National Science Foundation through the grant AST-1410155. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. This work is based on observations taken by the RELICS Treasury Program (GO-14096) with the NASA/ESAHST. Program GO-14096 is supported by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. The paper uses high level science products (HLSP) from the RELICS program, including catalogues and lens models, which were retrieved from the Mikulski Archive for Space Telescopes (MAST). Funding Information: We thank Xinnan Du, Anna Feltre, Taylor Hutchison, Alice Shapley, and Casey Papovich for helpful discussions. DPS acknowledges support from the National Science Foundation through the grant AST-1410155. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. This work is based on observations taken by the RELICS Treasury Program (GO-14096) with the NASA/ESAHST. Program GO-14096 is supported by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. The paper uses high level science products (HLSP) from the RELICS program, including catalogues and lens Publisher Copyright: {\textcopyright} 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society",
year = "2020",
month = may,
day = "1",
doi = "https://doi.org/10.1093/mnras/staa751",
language = "American English",
volume = "494",
pages = "719--735",
journal = "MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "1",
}