The SAMI–Fornax Dwarfs Survey – III. Evolution of [α/Fe] in dwarfs, from Galaxy Clusters to the Local Group

Autor(en)

J. Romero-Gómez, Reynier F. Peletier, J. A. L. Aguerri, Steffen Mieske, Nicholas Scott, Joss Bland-Hawthorn, Julia J. Bryant, Scott M. Croom, F. Sara Eftekhari, Jesús Falcón-Barroso, Michael Hilker, Glenn van de Ven, Aku Venhola

Abstrakt

Using very deep, high spectral resolution data from the SAMI Integral Field Spectrograph, we study the stellar population properties of a sample of dwarf galaxies in the Fornax Cluster, down to a stellar mass of 10

⁷ M

_☉, which has never been done outside the Local Group. We use full spectral fitting to obtain stellar population parameters. Adding massive galaxies from the ATLAS

^3D project, which we re-analysed, and the satellite galaxies of the Milky Way, we obtained a galaxy sample that covers the stellar mass range 10

⁴–10

¹² M

_☉. Using this large range, we find that the mass–metallicity relation is not linear. We also find that the [α/Fe]-stellar mass relation of the full sample shows a U-shape, with a minimum in [α/Fe] for masses between 10

⁹ and 10

¹⁰ M

_☉. The relation between [α/Fe] and stellar mass can be understood in the following way: when the faintest galaxies enter the cluster environment, a rapid burst of star formation is induced, after which the gas content is blown away by various quenching mechanisms. This fast star formation causes high [α/Fe] values, like in the Galactic halo. More massive galaxies will manage to keep their gas longer and form several bursts of star formation, with lower [α/Fe] as a result. For massive galaxies, stellar populations are regulated by internal processes, leading to [α/Fe] increasing with mass. We confirm this model by showing that [α/Fe] correlates with clustercentric distance in three nearby clusters and also in the halo of the Milky Way.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Instituto de Astrofísica de Canarias (IAC), Universidad de La Laguna, University of Groningen, European Southern Observatory (Chile), The University of Sydney, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), European Southern Observatory (Germany), University of Oulu

Journal

Monthly Notices of the Royal Astronomical Society

Band

522

Seiten

130-150

Anzahl der Seiten

21

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stad953

Publikationsdatum

06-2023

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/b15dc018-a8ba-474d-85a7-14dae735d1f4