SFR=0 galaxies

[changhoonhahn]

Due to mass and temporal resolutions of the simulations, a handful of galaxies have SFR=0 (see notebook). The dust model, which depends on log SSFR, cannot be directly used for these galaxies.

At the moment, I neglect these galaxies using an ad-hoc prescription for directly sampling their observables from the SDSS distribution of quiescent galaxies --- i.e. directly sampling M_r, G-R, FUV-NUV from SDSS quiescent galaxies. However, this is not ideal since this

• ignores the SFR dependence of quiescent galaxies (SFR=0 galaxies have lower SFR than SFR > 0 quiescent galaxies)
• affects the observable distribution of other quiescent galaxies.

Here's what happens when I sample the SFR between the range [0, SFR_min] for SFR=0 galaxies:

[changhoonhahn]

Here's how the color-magnitude relations look for two different prescriptions for SFR = 0

1. we assign the minimum non-zero SFR to all SFR=0 galaxies
2. we sample SFRs over the range [0, minimum non-zero SFR] to all SFR=0 galaxies I compared these two prescriptions in this notebook

1. most SFR=0 galaxies are not brighter than M_r < -20
2. produces very red FUV-NUV color

1. produces reasonable G-R colors, but too red FUV-NUV colors --- this would likely lead to a modification in the slopes of quiescent galaxies
2. produces G-R colors redder than the rest of the quiescent population. Same with FUV-NUV colors.

Based on these plots, prescription (1) seems more sensible.