Tidal radii and destruction rates of globular clusters in the Milky Way due to bulge-bar and disk shocking

TL;DR

This study models the orbits and destruction rates of 63 Milky Way globular clusters considering complex Galactic potential including a bar and spiral arms, revealing improved tidal radius estimates and differences in destruction rates due to non-axisymmetric features.

Contribution

It introduces a comprehensive analysis of globular cluster destruction rates using realistic Galactic potential models and Monte Carlo simulations to account for observational uncertainties.

Findings

Non-axisymmetric potential yields better tidal radius estimates.

Linear trajectory approximation is effective for bulge-shocking rates.

Destruction rates are generally lower in the non-axisymmetric potential for high-eccentricity clusters.

Abstract

We calculate orbits, tidal radii, and bulge-bar and disk shocking destruction rates for 63 globular clusters in our Galaxy. Orbits are integrated in both an axisymmetric and a non-axisymmetric Galactic potential that includes a bar and a 3D model for the spiral arms. With the use of a Monte Carlo scheme, we consider in our simulations observational uncertainties in the kinematical data of the clusters. In the analysis of destruction rates due to the bulge-bar, we consider the rigorous treatment of using the real Galactic cluster orbit, instead of the usual linear trajectory employed in previous studies. We compare results in both treatments. We find that the theoretical tidal radius computed in the nonaxisymmetric Galactic potential compares better with the observed tidal radius than that obtained in the axisymmetric potential. In both Galactic potentials, bulge-shocking destruction rates computed with a linear trajectory of a cluster at its perigalacticons give a good approximation to the result obtained with the real trajectory of the cluster. Bulge-shocking destruction rates for clusters with perigalacticons in the inner Galactic region are smaller in the non-axisymmetric potential, as compared with those in the axisymmetric potential. For the majority of clusters with high orbital eccentricities (e > 0.5), their total bulge+disk destruction rates are smaller in the non-axisymmetric potential.