2021/07/01 by Mario Llerena, M. Llerena, R. Amorín +27
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Lambda #Line (geometry) #Luminosity #Metallicity #Physics #Spectral line #Star (game theory) #Star formation #Stars #Stellar mass #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1051/0004-6361/202141651
published as A&A 659, A16 (2022) · Accepted for publication in A&A
openalex publication_date 2021/07/01 · arxiv created 2021/11/10 · arxiv updated 2022/03/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the mean properties of a large representative sample of 217 galaxies showing CIII] emission at 2<z<4, selected from a parent sample of ∼750 main-sequence star-forming galaxies in the VANDELS survey. These CIII] emitters have a broad range of UV luminosities, thus allowing a detailed stacking analysis to characterize their stellar mass, star formation rate (SFR) and stellar metallicity, as a function of the UV emission line ratios, EWs, and the carbon-to-oxygen (C/O) abundance ratio. Reliable CIII] detections represent ∼30% of the parent sample. Extreme CIII] emitters (EW(CIII])\gtrsim8Å) are exceedingly rare (∼3%) in VANDELS. The UV line ratios of the sample suggest no ionization source other than massive stars. Stacks with larger EW(CIII]) show larger EW(Lyα) and lower metallicity, but not all CIII] emitters are Lyα emitters. The stellar metallicities of CIII] emitters are not significantly different from that of the parent sample, increasing from ∼10% to ∼40% solar for stellar masses log(M⋆/M\odot)∼9-10.5. The stellar mass-metallicity relation of the CIII] emitters is consistent with previous works showing strong evolution from z=0 to z∼3. The C/O abundances of the sample range 35%-150% solar, with a noticeable increase with FUV luminosity and a smooth decrease with the CIII] EW. We discuss the CIII] emitters in the C/O-Fe/H and the C/O-O/H planes and find they follow stellar and nebular abundance trends consistent with those of Milky Way halo and thick disc stars and local HII galaxies, respectively. A qualitative agreement is also found with chemical evolution models, which suggests that CIII] emitters at z∼3 are experiencing an active phase of chemical enrichment.