Constraints on the in situ and ex situ stellar masses in nearby galaxies obtained with artificial intelligence

Autor(en)

Eirini Angeloudi, Jesús Falcón-Barroso, Marc Huertas-Company, Alina Boecker, Regina Sarmiento, Lukas Eisert, Annalisa Pillepich

Abstrakt

The hierarchical model of galaxy evolution suggests that mergers have a substantial impact on the intricate processes that drive stellar assembly within a galaxy. However, accurately measuring the contribution of accretion to a galaxy’s total stellar mass and its balance with in situ star formation poses a persistent challenge, as it is neither directly observable nor easily inferred from observational properties. Using data from MaNGA, we present theory-motivated predictions for the fraction of stellar mass originating from mergers in a statistically significant sample of nearby galaxies. Employing a robust machine learning model trained on mock MaNGA analogues (MaNGIA) obtained from a cosmological simulation (TNG50), we unveil that in situ stellar mass dominates almost across the entire stellar mass spectrum (10⁹ M_⊙ < M_⋆ < 10¹² M_⊙). Only in more massive galaxies (M_⋆ > 10¹¹ M_⊙) does accreted mass become a substantial contributor, reaching up to 35–40% of the total stellar mass. Notably, the ex situ stellar mass in the nearby Universe exhibits notable dependence on galaxy characteristics, with higher accreted fractions favoured being by elliptical, quenched galaxies and slow rotators, as well as galaxies at the centre of more massive dark matter haloes.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Instituto de Astrofísica de Canarias (IAC), Universidad de La Laguna, University of California, Santa Cruz, Université Paris-Cité, Max-Planck-Institut für Astronomie

Journal

Nature Astronomy

Band

8

Seiten

1310-1320

Anzahl der Seiten

11

ISSN

2397-3366

Publikationsdatum

10-2024

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

ASJC Scopus Sachgebiete

Astronomy and Astrophysics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/8da5ffbb-31c8-4d61-8df6-82fc9f97aabe