Interacting galaxies in the IllustrisTNG simulations -- VI: Reconstructed orbits, close encounters and mergers

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Autori principali: Patton, David R., Faria, Lawrence, Hani, Maan H., Torrey, Paul, Ellison, Sara L., Thakur, Shivani D., Westlake, Raven I.
Natura: Preprint
Pubblicazione: 2024
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author Patton, David R.
Faria, Lawrence
Hani, Maan H.
Torrey, Paul
Ellison, Sara L.
Thakur, Shivani D.
Westlake, Raven I.
author_facet Patton, David R.
Faria, Lawrence
Hani, Maan H.
Torrey, Paul
Ellison, Sara L.
Thakur, Shivani D.
Westlake, Raven I.
contents Cosmological simulations have been used to study interacting galaxies as a function of galaxy pair separation, enabling comparisons with observational studies of galaxy pairs. The study of interacting galaxies as a function of time (i.e. merger stage) has mostly been limited to high resolution merger simulations, due to the poor time sampling available in cosmological simulations. Building on an earlier study of galaxy pairs in the IllustrisTNG cosmological simulations, we reconstruct the orbits of galaxy pairs involving massive galaxies ($M_* > 10^{10}M_{\odot}$) at redshifts of $0 \leq z < 1$, using a novel kinematic interpolation scheme to model the orbits in between the IllustrisTNG snapshots (which are separated by 162 Myr on average). We assess the accuracy of these interpolations using a pre-existing suite of merger simulations, and find that kinematic interpolations provide a remarkable improvement in accuracy compared with interpolations that use only radial separations or 3D positions. We find that nearly 90 per cent of the closest pairs ($r < 25$ kpc) have had a pericentre encounter within the past Gyr. Many of these close pairs are found on rapidly shrinking orbits, and roughly 85 per cent of these pairs will merge within 1 Gyr. However, approximately 3 per cent of these close pairs appear to be flyby systems that will never merge. These reconstructed orbits will be used in future studies to investigate how and when galaxy properties change during close encounters and mergers between galaxies in IllustrisTNG.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17889
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Interacting galaxies in the IllustrisTNG simulations -- VI: Reconstructed orbits, close encounters and mergers
Patton, David R.
Faria, Lawrence
Hani, Maan H.
Torrey, Paul
Ellison, Sara L.
Thakur, Shivani D.
Westlake, Raven I.
Astrophysics of Galaxies
Cosmological simulations have been used to study interacting galaxies as a function of galaxy pair separation, enabling comparisons with observational studies of galaxy pairs. The study of interacting galaxies as a function of time (i.e. merger stage) has mostly been limited to high resolution merger simulations, due to the poor time sampling available in cosmological simulations. Building on an earlier study of galaxy pairs in the IllustrisTNG cosmological simulations, we reconstruct the orbits of galaxy pairs involving massive galaxies ($M_* > 10^{10}M_{\odot}$) at redshifts of $0 \leq z < 1$, using a novel kinematic interpolation scheme to model the orbits in between the IllustrisTNG snapshots (which are separated by 162 Myr on average). We assess the accuracy of these interpolations using a pre-existing suite of merger simulations, and find that kinematic interpolations provide a remarkable improvement in accuracy compared with interpolations that use only radial separations or 3D positions. We find that nearly 90 per cent of the closest pairs ($r < 25$ kpc) have had a pericentre encounter within the past Gyr. Many of these close pairs are found on rapidly shrinking orbits, and roughly 85 per cent of these pairs will merge within 1 Gyr. However, approximately 3 per cent of these close pairs appear to be flyby systems that will never merge. These reconstructed orbits will be used in future studies to investigate how and when galaxy properties change during close encounters and mergers between galaxies in IllustrisTNG.
title Interacting galaxies in the IllustrisTNG simulations -- VI: Reconstructed orbits, close encounters and mergers
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2402.17889