The Edge of the Milky Way Stellar Disk Revealed Using Clump Giant Stars as Distance Indicators

TL;DR

This study maps the Milky Way's stellar disk edge at approximately 13.9 kpc using clump giant stars as standard candles in near-infrared surveys, accounting for galactic warp effects.

Contribution

It introduces a method to precisely determine the Milky Way's stellar disk edge using calibrated clump giants from new near-IR surveys.

Findings

The stellar disk edge is at R=13.9±0.5 kpc.

The method accounts for galactic warp effects.

The approach enables detailed mapping of the galaxy's edge.

Abstract

We use the clump giants of the disk as standard candles calibrated from Hipparcos parallaxes in order to map their distribution with two new near-IR surveys of the Galactic plane: UKIDSS-GPS and VVV. We explore different selection cuts of clump giants. We conclude that there is an edge of the stellar disk of the Milky Way at R=13.9+/-0.5kpc along various lines of sight across the galaxy. The effect of the warp is considered, taking fields at different longitudes and above and below the plane. We demonstrate that the edge of the stellar disk of the Milky Way can now be mapped in the near infrared in order to test different models, and to establish our own place within the galaxy.