Simulations of high-redshift [OIII] emitters: Chemical evolution and multi-line diagnostics

Abstract

Recent observations by James Webb Space Telescope discovered a number of high-redshift galaxies with strong emission lines from doubly ionized oxygen. Combined with ALMA observations of farinfrared lines, multi-line diagnostics can be applied to the high-redshift galaxies in order to probe the physical conditions of the inter-stellar medium. We study the formation and evolution of galaxies using the FirstLight simulation suite, which provides outputs of 62 high-resolution, zoom-in galaxy simulations. We devise a physical model of Hii regions and calculate spatially resolved [Oiii] line emission. We show that massive galaxies with stellar masses of M * > 10 9 M chemically evolve rapidly to z = 9. Young stellar populations in the star-forming galaxies boost the [Oiii] line emission, rendering the ratio of line luminosity to star formation rate larger than that for low-redshift galaxies, which is consistent with recent observations. Measuring the flux ratios of rest-frame optical and far-infrared lines allows us to estimate the physical conditions such as density and metallicity of the star-forming gas in high-redshift [Oiii] emitters.

JWST Census for the Mass–Metallicity Star Formation Relations at z = 4–10 with Self-consistent Flux Calibration and Proper Metallicity Calibrators

“…Furthermore, our compilation of results does not show any significant evolution among the z = 4-10 sample. Theoretical simulations also predict a similar trend of small redshift evolution in the MZ relation at z ∼ 5-9 Ma et al 2016;Langan et al 2020;Ucci et al 2023;Nakazato et al 2023), with some simulations suggesting a potentially observable decrease in metallicity with redshift for a given mass (∼0.26 dex from z = 5 to 9; Torrey et al 2019). Although there may be a weak evolution toward lower metallicity at z > 8, the current sample has relatively large uncertainties in metallicity (D log (O/H) ∼ 0.3 dex), which makes it difficult to distinguish fully between the different predictions of redshift evolution at high redshift (z > 4), especially for low-mass galaxies with M å < 10 8 M e .…”

“…Similarly, the ILLUSTRISTNG predictions at z = 5, z = 7, and z = 9 are extrapolated from the results at z = 4, z = 6, and z = 6, respectively, using their redshift evolution function (D =log O H 0.08 ( ) dex from z = 4 to 5, −0.075 dex from z = 6 to 7, and −0.1 dex from z = 6 to 9). For the FIRSTLIGHT results, we refer to Langan et al (2020) and Nakazato et al (2023) to prove the low-mass and the massive regimes, respectively. We assume the z = 8 relation of Langan et al (2020) in panel (c), and the z = 6 relation of Nakazato et al (2023) in panel (a), assuming no strong evolution at z = 8-9 and z = 5-6, respectively.…”

“…For the FIRSTLIGHT results, we refer to Langan et al (2020) and Nakazato et al (2023) to prove the low-mass and the massive regimes, respectively. We assume the z = 8 relation of Langan et al (2020) in panel (c), and the z = 6 relation of Nakazato et al (2023) in panel (a), assuming no strong evolution at z = 8-9 and z = 5-6, respectively. For the FLARES results, we adopt the stellar metallicities of only young (<10 Myr) star particles and assume the stellar and gas-phase metallicities in the region of massive-star formation are comparable.…”

Detections of [C ii] 158 μm and [O iii] 88 μm in a Local Lyman Continuum Emitter, Mrk 54, and Its Implications to High-redshift ALMA Studies*

“…Using the photoionization models of CLOUDY constructed by Ferland et al (2013) depends on various parameters, we also make use of local analogs of high-z galaxies with FIR line spectroscopy (e.g., low stellar mass or gas-phase metallicity), the HDGS and the LITTLE THINGS Survey (LT; Hunter et al 2012;Cigan et al 2016Cigan et al , 2021, to statistically examine the correlations between [O III]/[C II] and other physical quantities such as ionization parameter, ionized-to-neutral gas volume filling factor, gas-phase metallicity, and burstiness. In light of recent combined observations of high-z galaxies with ALMA and JWST in the rest-frame optical and FIR (e.g., Bakx et al 2023), respectively, the presented study will be a reference study that is useful (1) to infer f esc of galaxies in the EoR and (2) to plan and interpret the ALMA +JWST observations (e.g., Kohandel et al 2023;Nakazato et al 2023).…”

Detections of [C II] 158 $μ$m and [O III] 88 $μ$m in a Local Lyman Continuum Emitter, Mrk 54, and its Implications to High-redshift ALMA Studies

“…Here, we report observations of the FIR lines in Mrk 54 using FIFI-LS (Field-Imaging Far-Infrared Line-Spectrometer, Fischer et al 2018) depends on various parameters, we also make use of local analogues of high-z galaxies with FIR line spectroscopy (e.g., low stellar mass or gas-phase metallicity), the HDGS and the LITTLE THINGS Survey (LT, Hunter et al 2012;Cigan et al 2016Cigan et al , 2021, to statistically examine the correlations between [O iii]/[C ii] and other physical quantities such as ionization parameter, ionized-to-neutral gas volume filling factor, gas-phase metallicity, and burstiness. In light of recent combined observations of high-z galaxies with ALMA and the James Webb Space Telescope (JWST) in the rest-frame optical and FIR (e.g., Bakx et al 2023), respectively, the presented study will be a reference study that is useful (1) to infer f esc of galaxies in the EoR and (2) to plan and interpret the ALMA+JWST observations (e.g., Nakazato et al 2023;Kohandel et al 2023).…”