A stream come true: Connecting tidal tails, shells, streams, and planes with galaxy kinematics and formation history

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Hauptverfasser: Valenzuela, Lucas M., Remus, Rhea-Silvia
Format: Preprint
Veröffentlicht: 2022
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author Valenzuela, Lucas M.
Remus, Rhea-Silvia
author_facet Valenzuela, Lucas M.
Remus, Rhea-Silvia
contents The rapidly improving quality and resolution of both low surface brightness observations and cosmological simulations of galaxies enables one to address the important question how the formation history is imprinted in the outer, unrelaxed regions of galaxies, and to inspect the correlations of such imprints with the internal kinematics. Using the hydrodynamical cosmological simulation Magneticum Pathfinder, we identify tidal tails, shells, streams, and satellite planes, and connect their existence to the amount of rotational support and the formation histories of the host galaxies. This presents the first combined statistical census considering all those four types of features in hydrodynamical cosmological simulations. Tidal features are visually classified from a 3D rendering of the simulated galaxies by several scientists. The results are compared to observations, especially from the MATLAS survey. Prominent features are more common around elliptical than around disk galaxies. Shells are preferentially found around kinematically slowly rotating galaxies in both simulations and observations, while streams only have a slight preference to be present around slowly rotating galaxies. Tails and satellite planes appear independently of the internal kinematics of the central galaxy, indicating that they are formed through processes that have not (yet) affected the internal kinematics. As shells are formed through radial merger events while streams are remnants of circular merger infall, this suggests that the orbital angular momentum of the merger event plays a more crucial role in transforming the host galaxy than previously anticipated. The existence of shells around slow rotators is further a sign of a radial merger formation for the particular slow rotators, as a third of the galaxies with a shell were transformed into slow rotators by the merger event that also caused the shells.
format Preprint
id arxiv_https___arxiv_org_abs_2208_08443
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A stream come true: Connecting tidal tails, shells, streams, and planes with galaxy kinematics and formation history
Valenzuela, Lucas M.
Remus, Rhea-Silvia
Astrophysics of Galaxies
The rapidly improving quality and resolution of both low surface brightness observations and cosmological simulations of galaxies enables one to address the important question how the formation history is imprinted in the outer, unrelaxed regions of galaxies, and to inspect the correlations of such imprints with the internal kinematics. Using the hydrodynamical cosmological simulation Magneticum Pathfinder, we identify tidal tails, shells, streams, and satellite planes, and connect their existence to the amount of rotational support and the formation histories of the host galaxies. This presents the first combined statistical census considering all those four types of features in hydrodynamical cosmological simulations. Tidal features are visually classified from a 3D rendering of the simulated galaxies by several scientists. The results are compared to observations, especially from the MATLAS survey. Prominent features are more common around elliptical than around disk galaxies. Shells are preferentially found around kinematically slowly rotating galaxies in both simulations and observations, while streams only have a slight preference to be present around slowly rotating galaxies. Tails and satellite planes appear independently of the internal kinematics of the central galaxy, indicating that they are formed through processes that have not (yet) affected the internal kinematics. As shells are formed through radial merger events while streams are remnants of circular merger infall, this suggests that the orbital angular momentum of the merger event plays a more crucial role in transforming the host galaxy than previously anticipated. The existence of shells around slow rotators is further a sign of a radial merger formation for the particular slow rotators, as a third of the galaxies with a shell were transformed into slow rotators by the merger event that also caused the shells.
title A stream come true: Connecting tidal tails, shells, streams, and planes with galaxy kinematics and formation history
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2208.08443