Tidal mass loss in the Fornax dwarf spheroidal galaxy through N-body simulations with Gaia DR3-based orbits

TL;DR

This study uses N-body simulations with Gaia DR3-based orbits to analyze tidal mass loss in the Fornax dwarf galaxy, finding stellar mass loss negligible and implications for globular cluster formation.

Contribution

It provides a detailed simulation-based analysis of Fornax's tidal mass loss using Gaia data, challenging previous assumptions about stellar stripping.

Findings

Stellar mass loss in Fornax is negligible despite dark matter loss.

Tidal stripping cannot explain the high stellar mass of Fornax's globular clusters.

Fornax's orbital parameters suggest minimal stellar mass loss over 12 Gyr.

Abstract

The Fornax dwarf spheroidal galaxy (dSph) represents a challenge for some globular cluster (GC) formation models, because an exceptionally high fraction of its stellar mass is locked in its GC system. In order to shed light on our understanding of GC formation, we aim to constrain the amount of stellar mass that Fornax has lost via tidal interaction with the Milky Way (MW). Exploiting the flexibility of effective multi-component $N$-body simulations and relying on state-of-the-art estimates of Fornax's orbital parameters, we study the evolution of the mass distribution of the Fornax dSph in observationally justified orbits in the gravitational potential of the MW over 12 Gyr. We find that, though the dark-matter mass loss can be substantial, the fraction of stellar mass lost by Fornax to the MW is always negligible, even in the most eccentric orbit considered. We conclude that stellar-mass loss due to tidal stripping is not a plausible explanation for the unexpectedly high stellar mass of the GC system of the Fornax dSph and we discuss quantitatively the implications for GC formation scenarios.