Low-metallicity Galaxies from the Dark Energy Survey
Abstract
We present a new selection of 358 blue compact dwarf galaxies (BCDs) from 5000 square degrees in the Dark Energy Survey, and the spectroscopic follow-up of a subsample of 68 objects. For the subsample of 34 objects with deep spectra, we measure the metallicity via the direct T_e method using the auroral [O III]λ 4363 emission line. These BCDs have an average oxygen abundance of 12+log(O/H) = 7.8, with stellar masses between 10⁷ and 10⁸M⊙ and specific star-formation rates between ∼10−⁹ and 10−⁷ yr⁻¹. We compare the position of our BCDs with the mass–metallicity (M–Z) and luminosity–metallicity (L–Z) relation derived from the Local Volume Legacy sample. We find the scatter about the M–Z relation is smaller than the scatter about the L–Z relation. We identify a correlation between the offsets from the M–Z and L–Z relation that we suggest is due to the contribution of metal-poor inflows. Finally, we explore the validity of the mass–metallicity–SFR fundamental plane in the mass range probed by our galaxies. We find that BCDs with stellar masses smaller than 10⁸M⊙ do not follow the extrapolation of the fundamental plane. This result suggests that mechanisms other than the balance between inflows and outflows may be at play in regulating the position of low-mass galaxies in the M–Z–SFR space.
Additional Information
© 2023. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. All the GALEX data used in this paper can be found in MAST: 10.17909/T9H59D. This research uses services or data provided by the Astro Data Lab at NSF's NOIRLab. NOIRLab is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation. MH is fellow of the Knut & Alice Wallenberg Foundation.Attached Files
Published - Lin_2023_ApJ_951_138.pdf
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Additional details
- Eprint ID
- 122397
- Resolver ID
- CaltechAUTHORS:20230725-745861000.21
- NSF
- Knut and Alice Wallenberg Foundation
- Created
-
2023-07-28Created from EPrint's datestamp field
- Updated
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2023-07-28Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)