Estimation of the Vertical Disk Scale Height Using Young Galactic Objects

TL;DR

This study estimates the vertical disk scale height of the Milky Way using various young Galactic objects, finding values between approximately 36 and 52 parsecs, depending on the object type, and excluding objects from the Local arm.

Contribution

It provides new estimates of the Galactic disk's vertical scale height using a large sample of young objects, excluding the Local arm, and applies a self-gravitating isothermal disk model.

Findings

Vertical scale height from masers: 46+/-5 pc

From OB associations: 36+/-3 pc

From HII regions: 35.6+/-2.7 pc

Abstract

We have collected literature data on young Galactic objects such as masers with VLBI-measured trigonometric parallaxes, OB associations, HII regions and Cepheids. We have recently established that vertical disk scale height is strongly influenced by the objects of the Local arm. In the present work we used samples that do not contain objects in this arm. Based on the model of a self-gravitating isothermal disk for the density distribution, we have found the following vertical disk scale heights: h=46+/-5 pc from 69 masers with trigonometric parallaxes, h=36+/-3 pc from 59 OB associations, h=35.6+/-2.7 pc from 147 HII regions, h=52.1+/-1.9 pc from 195 young Cepheids, and h=72.0+/-2.3 pc from 192 old Cepheids.