Infrared luminosity functions and dust mass functions in the EAGLE simulation

Abstract

We present infrared luminosity functions and dust mass functions for the EAGLE cosmological simulation, based on synthetic multi-wavelength observations generated with the SKIRT radiative transfer code. In the local Universe, we reproduce the observed infrared luminosity and dust mass functions very well. Some minor discrepancies are encountered, mainly in the high luminosity regime, where the EAGLE-SKIRT luminosity functions mildly but systematically underestimate the observed ones. The agreement between the EAGLE-SKIRT infrared luminosity functions and the observed ones gradually worsens with increasing lookback time. Fitting modified Schechter functions to the EAGLE-SKIRT luminosity and dust mass functions at different redshifts up to z = 1, we find that the evolution is compatible with pure luminosity/mass evolution. The evolution is relatively mild: within this redshift range, we find an evolution of L ,250 ∝ (1 + z) 1.68 , L ,TIR ∝ (1 + z) 2.51 and M ,dust ∝ (1 + z) 0.83 for the characteristic luminosity/mass. For the luminosity/mass density we find ε 250 ∝ (1 + z) 1.62 , ε TIR ∝ (1 + z) 2.35 and ρ dust ∝ (1 + z) 0.80 , respectively. The mild evolution of the dust mass density is in relatively good agreement with observations, but the slow evolution of the infrared luminosity underestimates the observed luminosity evolution significantly. We argue that these differences can be attributed to increasing limitations in the radiative transfer treatment due to increasingly poorer resolution, combined with a slower than observed evolution of the SFR density in the EAGLE simulation and the lack of AGN emission in our EAGLE-SKIRT post-processing recipe.

Reproducing submillimetre galaxy number counts with cosmological hydrodynamic simulations

“…This has been variously attributed to the lack of 'bursty' star formation in the E model (Furlong et al 2015), or to the strength of the AGN feedback (Katsianis et al 2017b). Whatever the cause, we speculate that the lack of highly star-forming galaxies is the primary reason for the corresponding dearth of bright 850 µm sources in E , as has recently been suggested by Baes et al (2020). Indeed, the discrepancy between E 's SFRF and IR observations at SFR> 100 M yr −1 is broadly similar to the discrepancy seen in their 850 µm number counts at 850 > 1 mJy.…”

“…A large fraction of galaxies in S have a higher DTM , particularly at < 5. This may explain in some part the general offset in infrared luminosity functions seen in the E model at > 1 (Baes et al 2020). [0.12, 0.2, 0.5, 0.8, 1.7, 3.2, 4.5, 6.7].…”

IllustrisTNG and S2COSMOS: possible conflicts in the evolution of neutral gas and dust

“…Dust masses were estimated using modified blackbody fits to synthetic infrared luminosities at FIR wavelengths (160, 250, 350 and 500 μm) generated using a postprocessing 3D radiative transfer procedure (Baes et al 2011;Camps & Baes 2015;Camps et al 2016Camps et al , 2018. Similarly to the results of this study, in the local universe (z < 0.1), Baes et al (2020) found that they could reproduce the shape and normalization of the DMF fairly well, getting very good agreement with the DMFs found by Dunne et al (2011) and Beeston et al (2018) for dust masses M d < 2 × 10 7 M but predicting too few galaxies at higher masses.…”

“…Recently, Baes et al (2020) derived DMFs out to z = 1 for galaxies from the EAGLE simulation. Dust masses were estimated using modified blackbody fits to synthetic infrared luminosities at FIR wavelengths (160, 250, 350 and 500 μm) generated using a postprocessing 3D radiative transfer procedure (Baes et al 2011;Camps & Baes 2015;Camps et al 2016Camps et al , 2018.…”

“…Schulz et al 2020;Vogelsberger et al 2020). A recent example of this is presented in Baes et al (2020), who examined the infrared luminosity functions and dust mass functions for galaxies from the EAGLE cosmological simulation (Crain et al 2015;Schaye et al 2015) for z < 1. Synthetic multiwavelength observations for EAGLE galaxies were generated using the radiative transfer code SKIRT (Baes et al 2011;Camps & Baes 2015;Camps et al 2016Camps et al , 2018.…”