Two estimates of the distance to the Galactic centre

TL;DR

This paper estimates the distance to the Galactic centre using globular cluster data, red clump calibration, and 2MASS star analysis, achieving consistent results around 7.4 to 7.5 kpc.

Contribution

It provides updated and reconciled estimates of the Galactic centre distance using multiple methods and recalibrated stellar indicators.

Findings

Distance estimate: 7.4 ± 0.2 kpc from globular clusters.

Red clump magnitude shows skewness, affecting calibration.

Distance from 2MASS stars: 7.5 ± 0.3 kpc, consistent with other methods.

Abstract

We use recently updated globular cluster distances to estimate the distance to the Galactic centre, finding 7.4 \pm 0.2|stat \pm 0.2|sys kpc from symmetry considerations. We recalibrate the red clump magnitude from Hipparcos stars, finding a skew distribution and a significant difference between peak and mean magnitudes. We find an estimate from stars in the periphery of the bulge using 2MASS, R0 = 7.5 \pm 0.3 kpc, in agreement with the figure from the halo centroid. We resolve discrepancies in the literature between estimates from the red clump. Our results are consistent with those found by different methodologies after taking systematic errors into account.