Open changhoonhahn opened 3 years ago
Latest updates to the slope-attenuation results from the updated SFR=0 prescription*
slope-attenuation relation of star-forming galaxies
slope-attenuation relation of galaxy subpopulations
TNG has a higher A_V range than EAGLE because TNG predicts intrinsically bluer galaxy populations.
With the updated SFR=0 prescription, we no longer see the unusual trend in quiescent TNG galaxies.
*The new prescription assigns SFR = SFR_min to SFR=0 galaxies
The fact that our dust model reproduces the attenuation-slope relation is neat since the relation is a result of dust scattering dominating at low attenuation and dust absorption dominating at high attenuation. We're able to infer the relation purely from the observations with a model that has no priors on it. This is a good demonstration of the forward modeling approach and its advantages. Other than that, I don't think we learn much from this comparison so I'm going to simplify the figure to:
Observations find a relationship between the slope and amplitude of dust attenuation in star-forming galaxies: galaxies with high attenuation have shallower slopes. For example in Salim & Narayanan (2020) they present the following relation for star-forming galaxies:
Current radiative transfer models are able to more-or-less reproduce this slope-attenuation relation: e.g. Chevellard+(2013) compared to Salim+(2018)
Trayford+(2020) compared to Salim+(2018) (red scatter points vs blue shaded)
Our dust model also more-or-less reproduce the slope-attenuation relation for star-forming galaxies:
Yet overall, our models find an overall steeper slope, especially at high attenuation.
Examining where different subpopulations of galaxies lie on the slope-attenuation relation sheds some light:
Blue and Green are star-forming. Blue has logSSFR > -9.75; Green has -9.75 > logSSFR > -10.5. Markers with black edges have M_* > 10^10.5Msun. (ignore the contours)
Lower mass star-forming galaxies have significantly shallower slopes. Our overall steeper slope is likely due to the fact that our sample has a high stellar mass limit.
Here's how the slope-attenuation relation looks for the entire galaxy population (including quiescent galaxies):
Orange (low SSFR), red (lower SSFR), purple (lowest SSFR) are all quiescent galaxies.
There's a couple of interesting points in these figures: