On the accretion of a new group of galaxies on to Virgo: II. The effect of pre-processing on the stellar population content of dEs

Author(s)

Bahar Bidaran, Francesco La Barbera, Anna Pasquali, Reynier Peletier, Glenn van de Ven, Eva K. Grebel, Jesus Falcón-Barroso, Agnieszka Sybilska, Dimitri A. Gadotti, Lodovico Coccato

Abstract

Using MUSE spectra, we investigate how pre-processing and accretion on to a galaxy cluster affect the integrated stellar population properties of dwarf early-type galaxies (dEs). We analyse a sample of nine dEs with stellar masses of ∼ 10⁹, M_⊙, which were accreted (∼2-3 Gyr ago) on to the Virgo cluster as members of a massive galaxy group. We derive their stellar population properties, namely age, metallicity ([M/H]), and the abundance ratio of α elements ([α/Fe]), by fitting observed spectral indices with a robust, iterative procedure, and infer their star formation history (SFH) by means of full spectral fitting. We find that these nine dEs are more metal-poor (at the 2-3σ level) and significantly more α-enhanced than dEs in the Virgo and Coma clusters with similar stellar mass, clustercentric distance, and infall time. Moreover, for six dEs, we find evidence for a recent episode of star formation during or right after the time of accretion on to Virgo. We interpret the high [α/Fe] of our sample of dEs as the result of the previous exposure of these galaxies to an environment hostile to star formation, and/or the putative short burst of star formation they underwent after infall into Virgo. Our results suggest that the stellar population properties of low-mass galaxies may be the result of the combined effect of pre-processing in galaxy groups and environmental processes (such as ram-pressure triggering star formation) acting during the early phases of accretion on to a cluster.

Organisation(s)

Department of Astrophysics

External organisation(s)

Scientific Software Center, INAF Astronomical Observatory of Capodimonte , University of Groningen, Institute of Astrophysics of the Canary Islands, University of La Laguna, Sybilla Technologies, European Southern Observatory (Germany), Durham University

Journal

Monthly Notices of the Royal Astronomical Society

Volume

515

Pages

4622-4638

No. of pages

17

DOI

https://doi.org/10.1093/mnras/stac2005

Publication date

09-2022

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/441bcd26-5643-4f1f-996a-27865c97bda0