Does the stellar distribution flare? A comparison of stellar scale heights with LAB HI data

TL;DR

This paper investigates whether stellar populations in the Milky Way exhibit flaring similar to HI gas, comparing observational evidence with LAB HI data and finding good agreement within uncertainties.

Contribution

It provides a comparative analysis of stellar flaring and HI gas flaring, challenging the assumption of constant stellar scale heights in the Milky Way.

Findings

Stellar populations show evidence of flaring at large galactocentric distances.

Good agreement found between stellar flaring and HI gas flaring data.

Results support the presence of variable stellar scale heights.

Abstract

The question, whether the stellar populations in the Milky Way take part in flaring of the scale heights as observed for the HI gas is a matter of debate. Standard mass models for the Milky Way assume a constant scale height for each of the different stellar distributions. However, there is mounting evidence that at least some of the stellar distributions reach at large galactocentric distances high altitudes that are incompatible with a constant scale height. We discuss recent observational evidence for stellar flaring and compare it with HI data from the Leiden/Argentine/Bonn (LAB) survey. Within the systemic and statistical uncertainties we find a good agreement between both.