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UNCERTAINTIES IN GALACTIC CHEMICAL EVOLUTION MODELS

Côté, Benoit; Côté, Benoît; Ritter, Christian; O’Shea, Brian W.; Herwig, Falk; Pignatari, Marco; Jones, Samuel; Fryer, Chris L.

Authors

Benoît Côté

Benoit Côté

Christian Ritter

Brian W. O’Shea

Falk Herwig

Samuel Jones

Chris L. Fryer

Abstract

We use a simple one-zone galactic chemical evolution model to quantify the uncertainties generated by the input parameters in numerical predictions for a galaxy with properties similar to those of the Milky Way. We compiled several studies from the literature to gather the current constraints for our simulations regarding the typical value and uncertainty of the following seven basic parameters: the lower and upper mass limits of the stellar initial mass function (IMF), the slope of the high-mass end of the stellar IMF, the slope of the delay-time distribution function of Type Ia supernovae (SNe Ia), the number of SNe Ia per M ⊙ formed, the total stellar mass formed, and the final mass of gas. We derived a probability distribution function to express the range of likely values for every parameter, which were then included in a Monte Carlo code to run several hundred simulations with randomly selected input parameters. This approach enables us to analyze the predicted chemical evolution of 16 elements in a statistical manner by identifying the most probable solutions, along with their 68% and 95% confidence levels. Our results show that the overall uncertainties are shaped by several input parameters that individually contribute at different metallicities, and thus at different galactic ages. The level of uncertainty then depends on the metallicity and is different from one element to another. Among the seven input parameters considered in this work, the slope of the IMF and the number of SNe Ia are currently the two main sources of uncertainty. The thicknesses of the uncertainty bands bounded by the 68% and 95% confidence levels are generally within 0.3 and 0.6 dex, respectively. When looking at the evolution of individual elements as a function of galactic age instead of metallicity, those same thicknesses range from 0.1 to 0.6 dex for the 68% confidence levels and from 0.3 to 1.0 dex for the 95% confidence levels. The uncertainty in our chemical evolution model does not include uncertainties relating to stellar yields, star formation and merger histories, and modeling assumptions.

Journal Article Type Article
Publication Date Jun 15, 2016
Journal The astrophysical journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 824
Issue 2
Article Number ARTN 82
Institution Citation Côté, B., Ritter, C., O’Shea, B. W., Herwig, F., Pignatari, M., Jones, S., & Fryer, C. L. (2016). UNCERTAINTIES IN GALACTIC CHEMICAL EVOLUTION MODELS. The Astrophysical journal, 824(2), https://doi.org/10.3847/0004-637X/824/2/82
DOI https://doi.org/10.3847/0004-637X/824/2/82
Keywords Galaxy : abundances; Galaxy : evolution; Stars : abundances
Publisher URL http://iopscience.iop.org/article/10.3847/0004-637X/824/2/82/meta
Additional Information Journal title: The Astrophysical Journal; Article type: paper; Article title: UNCERTAINTIES IN GALACTIC CHEMICAL EVOLUTION MODELS; Copyright information: © 2016. The American Astronomical Society. All rights reserved.; Date received: 2015-09-14; Date accepted: 2016-04-09; Online publication date: 2016-06-15

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