PREPRINT
048F142B-746E-46E5-806B-4A2952EE6C74

# Hermeian haloes in cosmological volumes

Anastasiia Osipova, Sergey Pilipenko, Stefan Gottlöber, Noam I. Libeskind, Oliver Newton, Jenny G. Sorce, Gustavo Yepes

Submitted on 15 September 2022

## Abstract

Recent studies based on numerical models of the Local Group predict the existence of field haloes and galaxies that have visited two distinct galaxies in the past, called Hermeian haloes. This work presents an analysis of the Hermeian haloes population in two high-resolution dark matter-only N-body simulations from the MultiDark suit (the ESMDPL, VSMDPL). Hermeian haloes make up from 0.5 to 2.5 per cent of the total number of field haloes depending on their mass. Furthermore, the results of our study suggest that at a sufficiently high resolution simulation, Hermeian haloes may be found around almost every halo, making them interesting for studies of matter exchange between galaxies. We find that about half (22 out of 49) of the selected Local Group analogues contain Hermeian haloes that passed through the haloes of both the Milky Way and M31 if the distance between the two main haloes is below 1 ${h}^{-1}\phantom{\rule{0.278em}{0ex}}\mathrm{Mpc}$; this fraction drops to one-fifth (24 out of 108) for distances of up to 1.5 ${h}^{-1}\phantom{\rule{0.278em}{0ex}}\mathrm{Mpc}$. We confirm earlier findings that unlike other field haloes, Hermeians are grouped along the line connecting the primary hosts of Local Group-like systems, which should facilitate their identification in observations. The vast majority of the Hermeian haloes, whose second target is a Milky Way analogue, are currently moving away from it with increased velocity compared to remaining field halo populations. Interestingly, the obtained data admits that NGC 3109 could have passed through the Andromeda Galaxy and the Milky Way earlier.

## Preprint

Comment: 13 pages, 13 figures, submitted to MNRAS

Subjects: Astrophysics - Astrophysics of Galaxies; Astrophysics - Cosmology and Nongalactic Astrophysics