The galaxy "missing dark matter" NGC1052-DF4 is undergoing tidal disruption (2010.09719v1)

Abstract: The existence of long-lived galaxies lacking dark matter represents a challenge to our understanding of how galaxies form. Here, we present evidence that explains the lack of dark matter in one of such galaxies: NGC1052-DF4. Deep optical imaging of the system has detected tidal tails in this object caused by its interaction with its neighbouring galaxy NGC1035. As stars are more centrally concentrated than the dark matter, the tidal stripping will remove a significant percentage of the dark matter before affecting the stars of the galaxy. Only ~7% of the stellar mass of the galaxy is in the tidal tails, suggesting that the stars of NGC1052-DF4 are starting only now to be affected by the interaction, while the percentage of remaining dark matter is <1%. This naturally explains the low content of dark matter inferred for this galaxy and reconciles these type of galaxies with our current models of galaxy formation.

• The paper demonstrates that tidal stripping, driven by gravitational interactions with a neighboring galaxy, explains the dark matter deficit in NGC1052-DF4.
• High-resolution imaging reveals tidal tails and quantifies that less than 1% of dark matter remains compared to a modest stellar mass extension.
• The results reinforce galaxy formation models by illustrating how environmental forces can preferentially remove dark matter from satellite galaxies.

Analysis of Tidal Disruption in NGC1052-DF4 and Its Implications on Dark Matter Content

The academic paper titled "The galaxy 'missing dark matter' NGC1052-DF4 is undergoing tidal disruption" by Montes et al. provides a detailed astrophysical investigation into the peculiar characteristics of the galaxy NGC1052-DF4. This paper addresses a deviation from conventional dark matter theories by positing a tidal disruption as the mechanism behind the observed depletion of dark matter in NGC1052-DF4, thereby aligning its behavior with current models of galaxy formation.

Summary of Findings

NGC1052-DF4 was previously noted for its unusual lack of dark matter, a characteristic that challenges existing paradigms of galaxy formation where dark matter is a fundamental component. This paper provides convincing evidence that the apparent lack of dark matter is due to tidal stripping, prompted by the gravitational interactions with a neighboring galaxy, NGC1035. High-resolution imaging reveals the presence of tidal tails in NGC1052-DF4, a classic indicator of such interactions.

Quantitatively, the research observed that only approximately 7% of the stellar mass resides in these tidal extensions, while less than 1% of the dark matter remains, suggesting that dark matter is preferentially stripped before the stars. This finding provides crucial insight into the dynamics of satellite galaxies and the spatial distribution of dark matter and stellar matter.

Implications for Galaxy Formation and Dark Matter Models

The implications of this research are multi-faceted. Firstly, the case paper of NGC1052-DF4 serves as a natural laboratory to explore the interactions between baryonic matter and dark matter in galaxies undergoing tidal disruption. It provides a clear example that corroborates theoretical predictions that dark matter is stripped more rapidly than stars due to its more diffuse distribution in galaxy halos.

Moreover, these findings bring light to the complexities of studying dark matter in low-surface-brightness galaxies, where traditional assumptions based on isolated systems might not hold. By resolving the paradox of the 'missing dark matter' in NGC1052-DF4, the paper emphasizes the necessity of considering environmental factors, such as tidal forces, in the evaluation of galactic dark matter content.

Prospects for Future Research

This research opens several pathways for further exploration. Future studies may focus on conducting detailed simulations of similar tidal stripping events to determine their prevalence and impact across different galactic environments. Comparative analysis with other ultra-diffuse galaxies suspected of low dark matter content might provide additional data points to verify the universality of these findings.

Additionally, advanced observational tools and methodologies should be employed to explore the outskirts of suspected galaxies with similar structural irregularities to NGC1052-DF4. This would enhance our understanding of dark matter distribution in interacting systems and expand our grasp of galaxy evolution influenced by external gravitational interactions.

In conclusion, the proposed tidal disruption hypothesis not only accounts for the anomalous properties of NGC1052-DF4 but also strengthens the existing framework of galaxy formation and evolution, emphasizing the significance of external environmental effects in shaping galactic structures and their dark matter halos.