The Tidal Tails of NGC 5466

TL;DR

This paper investigates the tidal tails of the globular cluster NGC 5466 using simulations to match observed structures, revealing insights into its mass loss, dynamics, and the importance of proper motion measurements.

Contribution

It provides the first detailed simulation-based analysis of NGC 5466's tidal tails, linking tail morphology to cluster dynamics and proper motion constraints.

Findings

NGC 5466's tails extend over 45 degrees in SDSS data.

The cluster is losing mass slowly, likely surviving another Hubble time.

Tidal effects at perigalacticon and disc crossing cause about 60% of mass loss.

Abstract

The study of substructure in the stellar halo of the Milky Way has made a lot of progress in recent years, especially with the advent of surveys like the Sloan Digital Sky Survey. Here, we study the newly discovered tidal tails of the Galactic globular cluster NGC 5466. By means of numerical simulations, we reproduce the shape, direction and surface density of the tidal tails, as well as the structural and kinematical properties of the present-day NGC 5466. Although its tails are very extended in SDSS data (> 45 degrees), NGC 5466 is only losing mass slowly at the present epoch and so can survive for probably a further Hubble time. The effects of tides at perigalacticon and disc crossing are the dominant causes of the slow dissolution of NGC 5466, accounting for about 60 % of the mass loss over the course of its evolution. The morphology of the tails provides a constraint on the proper motion -- the observationally determined proper motion has to be refined (within the stated error margins) to match the location of the tidal tails.