Constraining the vertical structure of the Milky Way rotation by microlensing in a finite-width global disk model

TL;DR

This study models the Milky Way's vertical mass distribution using a finite-width disk, combining microlensing and rotation gradient data to constrain the disk's structure and assess dark matter's role.

Contribution

It introduces a combined analysis of microlensing and rotation gradients within a finite-width disk model to constrain the Galaxy's vertical structure and dark matter contribution.

Findings

Disk width-scale is small, indicating a thin disk structure.

Non-baryonic dark matter contribution in the solar circle is insignificant.

Predicted vertical rotation gradients align with measurements.

Abstract

In this paper we model the vertical structure of mass distribution of the Milky Way galaxy in the framework of a finite-width global disk model. Assuming the Galactic rotation curve only, we test inside the solar orbit the predictions of the model for two measurable and unrelated to each other processes: the gravitational microlensing that allows to fix the disk width-scale by the best fit to measurements, and the vertical gradient of rotation modelled in the quasi-circular orbits approximation. The former is sensitive to the gravitating mass in compact objects and the latter is sensitive to all kinds of gravitating matter. The analysis points to a small width-scale of the considered disks and, at most, insignificant contribution of non-baryonic dark mater in the solar circle. The predicted high vertical gradient values in the rotation are consistent with the gradient measurements.