Establish whether enhanced birth-cloud attenuation is required in the broader post-starburst population

Establish whether accounting for birth-cloud dust attenuation substantially greater than the diffuse interstellar-medium attenuation is necessary for the more general population of CO-undetected and moderately CO-luminous post-starburst galaxies.

Background

The analysis finds that flexible spectrophotometric fits allowing enhanced birth-cloud attenuation are needed to reproduce the Paα-derived star formation rates of the three most CO-luminous L post-starburst galaxies. Models tying birth-cloud attenuation closely to diffuse interstellar-medium attenuation systematically underpredict the inferred instantaneous star formation rates in these extreme systems.

It remains unresolved whether the same dust geometry applies to the broader population of post-starburst galaxies, especially systems without CO detections or with more moderate CO luminosities. Resolving this issue would determine whether highly obscured residual star formation is a distinctive property of the most gas-rich objects or a general feature of post-starburst galaxies.

References

While it is not clear that accounting for such birth clouds is necessary for the more general population of CO-undetected post-starburst galaxies (or even the more moderately CO-luminous L galaxies), we conclude the most CO-luminous post-starburst galaxies still host significant star formation that is obscured in the rest-optical by strong dust attenuation.

— SQuIGG$\vec{L}$E: Spatially resolved NIRSpec Pa$α$ reveals that the most CO-luminous, $z\sim0.7$ post-starburst galaxies exhibit falling---but still active---star formation behind optically thick dust  (2609.31307 - Setton et al., 25 Sep 2026) in Section 3.5, “The global star formation rate”