The distribution of stellar orbits in Eagle galaxies - the effect of mergers, gas accretion, and secular evolution
- Autor(en)
- Giulia Santucci, Claudia Del P. Lagos, Katherine E. Harborne, Aaron Ludlow, Katy L. Proctor, Caro Foster, Richard McDermid, Adriano Poci, Sabine Thater, Glenn van de Ven, Ling Zhu, Daniel Walo Martin
- Abstrakt
The merger history of a galaxy is thought to be one of the major factors determining its internal dynamics, with galaxies having undergone different types or mergers (e.g. dry, minor or major mergers) predicted to show different dynamical properties. We study the instantaneous orbital distribution of galaxies in the Eagle simulation, colouring the orbits of the stellar particles by their stellar age, in order to understand whether stars form in particular orbits (e.g. in a thin or thick disc). We first show that Eagle reproduces well the observed stellar mass fractions in different stellar orbital families as a function of stellar mass and spin parameter at z = 0. We find that the youngest stars reside in a thin disc component that can extend to the very inner regions of galaxies, and that older stars have warmer orbits, with the oldest ones showing orbits consistent with both hot and counter-rotating classifications, which is consistent with the trend found in the Milky-Way and other disc galaxies. We also show that counter-rotating orbits trace galaxy mergers - in particular dry mergers, and that in the absence of mergers, counter-rotating orbits can also be born from highly misaligned gas accretion that leads to star formation.
- Organisation(en)
- Institut für Astrophysik
- Externe Organisation(en)
- Chinese Academy of Sciences (CAS), University of Western Australia, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), University of New South Wales, Macquarie University, Durham University
- Journal
- Monthly Notices of the Royal Astronomical Society
- Band
- 528
- Seiten
- 2326-2345
- Anzahl der Seiten
- 20
- ISSN
- 0035-8711
- Publikationsdatum
- 02-2024
- Peer-reviewed
- Ja
- ÖFOS 2012
- 103003 Astronomie, 103004 Astrophysik
- Schlagwörter
- ASJC Scopus Sachgebiete
- Astronomy and Astrophysics, Space and Planetary Science
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/b7131bc8-6539-433f-8cf3-2335f54e719b