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Accepted manuscript

Radial velocities and stellar populations for a sample of MATLAS survey dwarfs

Published online by Cambridge University Press:  15 July 2025

Kate Southon Open the ORCID record for Kate Southon [Opens in a new window] ,
Jonah S. Gannon Open the ORCID record for Jonah S. Gannon [Opens in a new window] ,
Duncan A. Forbes Open the ORCID record for Duncan A. Forbes [Opens in a new window] ,
Arsen Levitskiy ,
Maria Luisa Buzzo ,
Aaron J. Romanowsky  and
Jean P. Brodie
Kate Southon
Affiliation:
School of Physical and Chemical Sciences – Te Kura Matū, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand Centre for Astrophysics and Supercomputing, Swinburne University, John Street, Hawthorn VIC 3122, Australia
Jonah S. Gannon
Affiliation:
Centre for Astrophysics and Supercomputing, Swinburne University, John Street, Hawthorn VIC 3122, Australia
Duncan A. Forbes
Affiliation:
Centre for Astrophysics and Supercomputing, Swinburne University, John Street, Hawthorn VIC 3122, Australia
Arsen Levitskiy
Affiliation:
Centre for Astrophysics and Supercomputing, Swinburne University, John Street, Hawthorn VIC 3122, Australia
Maria Luisa Buzzo
Affiliation:
Centre for Astrophysics and Supercomputing, Swinburne University, John Street, Hawthorn VIC 3122, Australia
Aaron J. Romanowsky
Affiliation:
Department of Physics and Astronomy, San José State University, One Washington Square, San Jose, CA 95192, USA Department of Astronomy & Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
Jean P. Brodie
Affiliation:
Centre for Astrophysics and Supercomputing, Swinburne University, John Street, Hawthorn VIC 3122, Australia Department of Astronomy & Astrophysics, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
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Abstract

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Spectroscopic observations are essential for confirming associations, measuring kinematics, and determining stellar populations in dwarf galaxies. Here, we present Keck CosmicWeb Imager (KCWI) spectra for 12 MATLAS survey dwarfs. For 9, we confirm recession velocities consistent with their literature-assumed host galaxies. We propose revisions of the host galaxy associations for MATLAS-631, 1494, and 1938. For MATLAS-1494, our measured redshift reclassifies it from an ultra-diffuse galaxy candidate to a dwarf galaxy that is of smaller physical size and places it in the field. It also appears old and passive, providing a challenge to models that invoke quenching by tidal effects. Additionally, we measure stellar population estimates for 7 of the 12 galaxies, finding a ‘mixed bag’ of old quenched galaxies and those that are currently forming stars. Compared to the literature we find generally younger ages and higher metallicities. This result may help reconcile the observed offset of MATLAS survey dwarf galaxies from the universal stellar mass–metallicity relationship reported by Heesters et al. (2023).

Keywords

galaxies: distances and redshiftsgalaxies: dwarfgalaxies: evolutiongalaxies: general

Information

Type
Research Article
Information
Publications of the Astronomical Society of Australia , Accepted manuscript , pp. 1 - 12
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Astronomical Society of Australia