Impact of Dynamical Friction on the Tidal Formation of NGC 1052-DF2

TL;DR

This study uses N-body simulations to show that dynamical friction accelerates the formation of dark matter-deficient galaxies like NGC 1052-DF2 by promoting earlier tidal stripping, expanding possible formation scenarios.

Contribution

It introduces the role of dynamical friction in the tidal formation of DMDGs, demonstrating its impact on orbital decay and formation timescales, which was previously overlooked.

Findings

Dynamical friction accelerates orbit decay and DM-deficient formation by 3-4 Gyr.

Globular clusters show elevated velocity dispersion during DM-deficient phase.

Phase space features indicate pericentre passage, aiding observational identification.

Abstract

The formation of dark matter-deficient galaxies (DMDGs) through tidal interactions has been a subject of growing interest, particularly with the discovery of galaxies such as NGC 1052-DF2. Previous studies suggested that strong tidal forces could strip dark matter from satellite galaxies, but the role of dynamical friction in this process has been largely overlooked. In this paper, we present self-consistent N-body simulations that incorporate the effects of dynamical friction on the tidal formation of DF2, and compare them with the one without dynamical friction. We find that dynamical friction significantly accelerates the decay of the satellite galaxy's orbit, causing it to experience more frequent tidal stripping and leading to the earlier formation of a DM-deficient state, approximately 7-8 Gyr after infall. This is a few Gyr earlier than simulations without dynamical friction. Our results suggest that DMDGs can form in a wider range of orbital configurations, particularly on more circular orbits, than previously thought. Furthermore, we find that globular clusters in the DM-deficient phase exhibit elevated velocity dispersion, providing an observational signature of this evolutionary stage. We also examine the evolution of satellite in the phase space of total energy versus angular momentum, and show that a vertically narrow feature in this phase space is a clear signature of pericentre passage. These findings broaden the understanding of how DMDGs form and highlight the critical role of dynamical friction in shaping the evolutionary history of satellite galaxies in massive halos.