Manganese Indicates a Transition from Sub- to Near-Chandrasekhar Type Ia Supernovae in Dwarf Galaxies
Abstract
Manganese abundances are sensitive probes of the progenitors of Type Ia supernovae (SNe Ia). In this work, we present a catalog of manganese abundances in dwarf spheroidal satellites of the Milky Way, measured using medium-resolution spectroscopy. Using a simple chemical evolution model, we infer the manganese yield of SNe Ia in the Sculptor dwarf spheroidal galaxy (dSph) and compare to theoretical yields. The sub-solar yield from SNe Ia ([(Mn/Fe)_(Ia) = -0.30_(-0.03)^(+0.03) at [Fe/ H] = −1.5 dex, with negligible dependence on metallicity) implies that sub-Chandrasekhar-mass (sub-M_(Ch)) white dwarf progenitors are the dominant channel of SNe Ia at early times in this galaxy, although some fraction (≳ 20%) of M_(Ch) Type Ia or Type Iax SNe are still needed to produce the observed yield. First-order corrections for deviations from local thermodynamic equilibrium increase the inferred [(Mn/Fe)]_Ia by as much as ~0.3 dex. However, our results also suggest that the nucleosynthetic source of SNe Ia may depend on environment. In particular, we find that dSphs with extended star formation histories (Leo I, Fornax dSphs) appear to have higher [Mn/Fe] at a given metallicity than galaxies with early bursts of star formation (Sculptor dSph), suggesting that M Ch progenitors may become the dominant channel of SNe Ia at later times in a galaxy's chemical evolution.
Additional Information
© 2020. The American Astronomical Society. Received 2019 October 11; revised 2020 February 4; accepted 2020 February 5; published 2020 March 6. The authors thank I. Escala and G. Duggan for informing parts of the data pipeline, as well as A. Piro and A. McWilliam for helpful discussions and comments. This material is based upon work supported by the National Science Foundation under grant No. AST-1847909. M.A.dl.R. acknowledges the financial support of the NSF Graduate Research Fellowship Program. E.N.K. gratefully acknowledges support from a Cottrell Scholar award administered by the Research Corporation for Science Advancement as well as funding from generous donors to the California Institute of Technology. I.R.S. was supported by the Australian Research Council through grant No. FT160100028. The authors wish to recognize and acknowledge the deep cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this sacred mountain. Finally, we would like to express our deep gratitude to the staff at academic and telescope facilities, particularly those whose communities are excluded from the academic system, but whose labor maintains spaces for scientific inquiry. Facility: Keck:II (DEIMOS). - Software: spec2d (Cooper et al. 2012; Newman et al. 2013), Matplotlib (Hunter 2007), Astropy (Robitaille et al. 2013), Scipy (Jones et al. 2001), MOOG (Sneden et al. 2012), ATLAS9 (Castelli & Kurucz 2003).Attached Files
Published - de_los_Reyes_2020_ApJ_891_85.pdf
Accepted Version - 2001.01716.pdf
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Additional details
- Eprint ID
- 101746
- Resolver ID
- CaltechAUTHORS:20200306-133727979
- NSF
- AST-1847909
- NSF Graduate Research Fellowship
- Cottrell Scholar of Research Corporation
- Caltech
- Australian Research Council
- FT160100028
- Created
-
2020-03-06Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department