New Model Explains Energy Changes in Galaxy Shell Formation

A new semi-analytical model has been developed to understand the energy evolution in the progenitor of galaxy shells. This model focuses on the stellar shells surrounding elliptical galaxies, which are remnants of dwarf galaxies disrupted during merging events. The research, conducted by Beibei Guo and colleagues, highlights how the self-gravity of the progenitor affects the energy and angular momentum of particles during their initial infall into a larger galaxy.

Key findings include:

• The model describes changes in energy ($\Delta E_i$) and angular momentum ($\Delta Lz_i$) for particles, indicating that these changes are significant in broadening the initial energy distribution of progenitor models like Plummer or Hernquist.
• Following the disintegration of the progenitor potential, particles transition from being bound by self-gravity to moving within the gravitational potential of the target galaxy.
• The relationship between the radial period and the energy of particles undergoing radial motion is investigated, emphasizing the importance of accurately modeling the energy range of the dwarf galaxy at the time of disruption.
• The findings suggest that understanding these energy changes is crucial for predicting the number of observable shells around galaxies.

This research contributes to the broader understanding of galaxy formation and evolution, particularly how smaller galaxies interact and merge to form larger structures. The implications of this work could enhance our knowledge of the dynamics involved in galaxy mergers and the resulting stellar distributions.

The paper titled "Energy evolution in the progenitor of galaxy shells: a semi-analytical model" can be accessed here.