The growth of bulges and discs in relatively HI-rich galaxies: indication from HI scaling relations

TL;DR

This study investigates how the properties of bulges and discs in HI-rich galaxies relate to their HI content, revealing that HI mass fraction correlates with disc colors but not bulge colors, suggesting different roles in galaxy evolution.

Contribution

It provides new insights into the distinct relationships between HI content and galaxy components, highlighting that HI influences disc formation but not bulge growth.

Findings

Disc colors correlate with HI mass fraction at fixed stellar mass.

Bulge colors show no correlation with HI mass fraction.

No evidence that bulges quench star formation in discs.

Abstract

We study the relation between the properties of the bulge/disc components and the HI mass fraction of galaxies. We find that at fixed stellar mass, disc colours are correlated with the HI mass fraction, while bulge colours are not. The lack of a correlation between the bulge colour and the HI mass fraction is regardless whether the bulges are pseudo, or whether the galaxies host bars or are interacting with a neighbour. There is no strong correlation between the colours of the discs and bulges either. These results suggest that the current total amount of HI is closely related to the formation of discs, but does not necessarily fuel the formation of (pseudo) bulges in an efficient way. We do not find evidence for the star formation in the discs to be quenched by the bulges.