Context. Neutral-oxygen [OI] far-infrared emission lines at 63 μm and 145 μm are powerful probes of the physical conditions in the interstellar medium, although they have not been fully exploited in high-redshift studies. Aims. We investigate the connection between [OI] emission lines and key galaxy properties such as star formation rate (SFR) and H2 content. Our predictions are compared with existing observations and new data analyzed in this work. Methods. We post-process the outputs of the ColdSIM cosmological simulations with the DESPOTIC model, taking into account [OI] 63μm self-absorption by cold foreground material. A random forest algorithm was employed to accelerate computations, and new observational ALMA data for galaxies at redshift z ≃ 5–7 were used to validate our model. Results. Our predictions show significant [OI] 63μm luminosities (≈108L⊙) for galaxies with SFRs of ≈102M⊙yr-1. The [OI] 145μm line luminosity is typically 15% of the [OI] 63μm one an is a factor ≈2-20 below high-z observations. Both [OI] lines correlate with the SFR and molecular mass, but they exhibit flattening i scaling relationsith metallicity and stellar mass. Foreground selfabsorption reduces the [OI] 63μmflux by a factor of two to four, which is consistent with empirical coorrections in observational studies. We find typical line ratios of [OI] 63μ=[CII] 158μm ≈ 1 and [OI] 145μm=[CII] 158μm ≈ 0:2, consistent with z ≳ 6 observations, but only when [OI] 63μm self-absorption is included. Conclusions. The [OI] 63μm and [OI] 145μm lines both serve as tracers of star formation and molecular gas at high redshift. Their joint detection can provie constraints on the properties of the early interstellar medium and self-absorption of the [OI] 63μm line.
High- z [OI] emission lines: COLDSIM simulations and ALMA observations
Bischetti, M.;
2026-01-01
Abstract
Context. Neutral-oxygen [OI] far-infrared emission lines at 63 μm and 145 μm are powerful probes of the physical conditions in the interstellar medium, although they have not been fully exploited in high-redshift studies. Aims. We investigate the connection between [OI] emission lines and key galaxy properties such as star formation rate (SFR) and H2 content. Our predictions are compared with existing observations and new data analyzed in this work. Methods. We post-process the outputs of the ColdSIM cosmological simulations with the DESPOTIC model, taking into account [OI] 63μm self-absorption by cold foreground material. A random forest algorithm was employed to accelerate computations, and new observational ALMA data for galaxies at redshift z ≃ 5–7 were used to validate our model. Results. Our predictions show significant [OI] 63μm luminosities (≈108L⊙) for galaxies with SFRs of ≈102M⊙yr-1. The [OI] 145μm line luminosity is typically 15% of the [OI] 63μm one an is a factor ≈2-20 below high-z observations. Both [OI] lines correlate with the SFR and molecular mass, but they exhibit flattening i scaling relationsith metallicity and stellar mass. Foreground selfabsorption reduces the [OI] 63μmflux by a factor of two to four, which is consistent with empirical coorrections in observational studies. We find typical line ratios of [OI] 63μ=[CII] 158μm ≈ 1 and [OI] 145μm=[CII] 158μm ≈ 0:2, consistent with z ≳ 6 observations, but only when [OI] 63μm self-absorption is included. Conclusions. The [OI] 63μm and [OI] 145μm lines both serve as tracers of star formation and molecular gas at high redshift. Their joint detection can provie constraints on the properties of the early interstellar medium and self-absorption of the [OI] 63μm line.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
