# Energy balance SED modelling can be effective at high redshifts regardless of UV-FIR offsets

**Authors:** P. Haskell, D. J. B. Smith, R. K. Cochrane, C. C. Hayward, D. Anglés-Alcázar  
**arXiv:** [2309.07960](https://arxiv.org/abs/2309.07960)  
**Date:** 2023-09-14  
**Summary page:** https://www.summarizepaper.com/en/paper/2309.07960v1/

## Key points

- Recent studies have raised concerns about the effectiveness of energy balance spectral energy distribution (SED) fitting codes for studying high-redshift galaxies with spatially offset ultraviolet and far-infrared emission.
- Spatial decoupling can lead to miscalculations in the overall energetics by energy balance codes, potentially hindering the recovery of true properties of these galaxies.
- A team of researchers conducted a study to evaluate the performance of the SED fitting code Magphys in recovering various properties of dusty, high-redshift galaxies.
- They generated 6,706 synthetic SEDs from four zoom-in simulations using dust continuum radiative transfer from the FIRE project.
- The team aimed to recover parameters such as stellar mass, star formation rate (SFR), specific SFR, dust mass, and luminosity.
- By comparing their results with fits based solely on starlight or dust emissions alone, they demonstrated the importance of considering multi-wavelength data alongside an energy balance criterion.
- Overall, they achieved acceptable fits for 83% of the synthetic SEDs.
- The success rate decreased significantly beyond a redshift of approximately 4 due to sparser sampling of priors at earlier times when star formation histories (SFHs) must be physically plausible within age constraints imposed by the Universe's age.
- Validation using ground truth information from simulations showed that when fit quality was acceptable, Magphys estimates were independent of UV-FIR offset degree and performed similarly to previous reports on local galaxies.

## Summary

Recent studies have raised concerns about the effectiveness of energy balance spectral energy distribution (SED) fitting codes for studying high-redshift galaxies with spatially offset ultraviolet and far-infrared emission. These offsets, also known as spatial decoupling, can lead to miscalculations in the overall energetics by energy balance codes, potentially hindering the recovery of true properties of these galaxies. To address this issue, a team of researchers conducted a study to evaluate the performance of the SED fitting code Magphys in recovering various properties of dusty, high-redshift galaxies. They generated 6,706 synthetic SEDs from four zoom-in simulations of these galaxies using dust continuum radiative transfer from the FIRE project. The team aimed to recover parameters such as stellar mass, star formation rate (SFR), specific SFR, dust mass, and luminosity. By comparing their panchromatic results spanning wavelengths from 0.4 to 500 μm and covering a redshift range of 1 < z < 8 with fits based solely on starlight or dust emissions alone, they demonstrated the importance of considering multi-wavelength data alongside an energy balance criterion. Overall, they achieved acceptable fits for 83% of the synthetic SEDs. However, they observed that the success rate decreased significantly beyond a redshift of approximately 4 due to sparser sampling of priors at earlier times when star formation histories (SFHs) must be physically plausible within the age constraints imposed by the Universe's age. To validate their findings, they used ground truth information from simulations and found that when the quality of fit was acceptable, Magphys estimates were independent of UV-FIR offset degree and performed similarly to previous reports on local galaxies.