Dust in Galaxies over Cosmic Times

This week’s blog post had to be about Trevor Butrum’s paper coming out on astro-ph!

A comparison of dust content and properties in GAMA/G10-COSMOS/3D-HST and SIMBA cosmological simulations

Trevor Butrum (University of Louisville), Benne Holwerda (University of Louisville), Romeel Dave (University of Edinburgh), Kyle Cook (University of Louisville), Clayton Robertson (University of Louisville), Jochen Liske(University of Hamburg)

https://arxiv.org/abs/2505.02359

This all started with an off-the wall idea I had following the work by Driver+ 2018. There the emphasis was on the volume densities of some of the main components of galaxies we can infer from their light; their stellar mass, their current star-formation and their dust content.

The neat trick for that paper was to sum the luminosity functions and get a volume density. This was a neat approach as it used a heterodyne mix of surveys, GAMA, G10/COSMOS and the 3D-HST survey for ever increasing distances. This creates some gaps in the coverage as you can see very nicely in Trevor’s first plot:

The complete data sets of GAMA, G10-COSMOS, 3D-HST with stellar mass

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But the mass range 7 to 11 is reasonably covered. The idea I had was to compare the dust masses inferred for galaxies by the SED fits from Driver+ 2018 with those predicted in The Simba simulations. These are good volume and reasonable physics SAMs that seem to be doing a good job on the dust household (including ejection).

The dust mass ranges selected for this study. We plot GAMA/G10-COSMOS/3D-HST data as black dots. We plot the selected data with the ranges applied in green dots with a box surrounding them. The red dotted line represents the dust mass volume limits of the surveys. Note that we exclude GAMA data at z=0.5 due to volume-related issues in the selections. Selection effects were a real challenge. 

So we picked four slices in the Driver+ data and compared them to The Simba catalog at the same redshift/epoch. Simple no?

Normalized counts of stellar mass from Simba and GAMA/G10-COSMOS/3D-HST. The observational dataset is separated into individual surveys to highlight the distinctions between them. Trevor figured out how to make these mass functions completely on his own! 

And that is what Trevor did! And it worked. Reasonably well. It is of course quite instructive as well to see where itdidn’t work as well. And that occupied quite a bit of Trevor’s time.

And there is some work for the next generations of galaxy evolutionary models. Simba misses dust-rich galaxies for all epochs above z=0 and Simba does not accurately model low-dust mass galaxies at earlier epochs.