Imperial College London
Portrait Picture

Professor David van Dyk

Faculty of Natural Sciences, Department of Mathematics

Chair in Statistics
 
 
 
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Contact

 

+44 (0)20 7594 8574d.van-dyk Website

 
 
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Assistant

 

Mr David Whittaker +44 (0)20 7594 8481

 
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Location

 

539Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Yu:2018:1538-4357/aadfdd,
author = {Yu, X and Del, Zanna G and Stenning, D and Cisewski-Kehe, J and Kashyap, V and Stein, N and van, Dyk D and Warren, H and Weber, MA},
doi = {1538-4357/aadfdd},
journal = {The Astrophysical Journal: an international review of astronomy and astronomical physics},
title = {Incorporating uncertainties in atomic data Into the analysis of solar and stellar observations: a case study in Fe XIII},
url = {http://dx.doi.org/10.3847/1538-4357/aadfdd},
volume = {866},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Information about the physical properties of astrophysical objects cannot be measured directly but is inferred by interpreting spectroscopic observations in the context of atomic physics calculations. Ratios of emission lines, for example, can be used to infer the electron density of the emitting plasma. Similarly, the relative intensities of emission lines formed over a wide range of temperatures yield information on the temperature structure. A critical component of this analysis is understanding how uncertainties in the underlying atomic physics propagate to the uncertainties in the inferred plasma parameters. At present, however, atomic physics databases do not include uncertainties on the atomic parameters and there is no established methodology for using them even if they did. In this paper we develop simple models for uncertainties in the collision strengths and decay rates for Fe xiii and apply them to the interpretation of density-sensitive lines observed with the EUV (extreme ultraviolet) Imagining spectrometer (EIS) on Hinode. We incorporate these uncertainties in a Bayesian framework. We consider both a pragmatic Bayesian method where the atomic physics information is unaffected by the observed data, and a fully Bayesian method where the data can be used to probe the physics. The former generally increases the uncertainty in the inferred density by about a factor of 5 compared with models that incorporate only statistical uncertainties. The latter reduces the uncertainties on the inferred densities, but identifies areas of possible systematic problems with either the atomic physics or the observed intensities.
AU  - Yu,X
AU  - Del,Zanna G
AU  - Stenning,D
AU  - Cisewski-Kehe,J
AU  - Kashyap,V
AU  - Stein,N
AU  - van,Dyk D
AU  - Warren,H
AU  - Weber,MA
DO  - 1538-4357/aadfdd
PY  - 2018///
SN  - 0004-637X
TI  - Incorporating uncertainties in atomic data Into the analysis of solar and stellar observations: a case study in Fe XIII
T2  - The Astrophysical Journal: an international review of astronomy and astronomical physics
UR  - http://dx.doi.org/10.3847/1538-4357/aadfdd
UR  - http://hdl.handle.net/10044/1/64083
VL  - 866
ER  -
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