Host Properties

[YourVoicee]

Hello! I would like to ask for your assistance once again. I have been examining research papers (for example van Velzen et al 2021 ApJ 908 4) that utilize the prospector tool to infer the properties of galaxies. In an attempt to replicate these results, I have encountered difficulty in finding a comprehensive explanation of the parameters listed in the tables provided in the papers:

• The "u-r" parameter, which is defined as the extinction-corrected, synthetic rest-frame u − r color.
• The "dust model optical depth E(B-V)", which seems to represent the optical depth of the dust model with respect to E(B-V). However, it appears that "dust1" and "dust2" may have different meanings.

Could you kindly clarify whether these parameters are 'dependent' variables or if they are derived using other parameters?

I sincerely appreciate your assistance in advance.

[jrleja]

Hi,

Neither of these variables are explicit in Prospector. They instead are derived from the output spectra and/or photometry (u-r) and/or the definitions of dust1, dust2 combined with the attenuation curves as detailed in the FSPS manual ($SPS_HOME/doc/MANUAL.pdf). Ideally this should be done by calculating the corresponding E(B-V) and u-r rest-frame color for each posterior sample and in this way constructing a full posterior for these quantities, after which one can calculate the posterior median or any other desired moments.

If you'd like to reproduce these outputs, I'd suggest consulting the authors of this work to figure out their exact methodology.

Hope this helps, Joel

[YourVoicee]

Thank you for responding and your help!