k-corrections and spectroscopic diversity of SNe Ia
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Transcript of k-corrections and spectroscopic diversity of SNe Ia
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k-corrections and spectroscopic diversity of SNe Ia
Eric Y. HsiaoUniversity of Victoria
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k-corrections of SNe Ia
converts an observed magnitude to that which would be observed in the rest frame in another filter
usually depends on an assumed spectral distribution (spectral template)
spectroscopic diversity causes k-correction errors
Eric Y. Hsiao
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broadband colors
Eric Y. Hsiao
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spectral templateprocedures
quantify the feature strengths of the library spectra
determine the weighted mean feature strength at each epoch and wavelength
adjust a base spectral template to the weighted mean feature strengths
Eric Y. Hsiao
Hsiao et al. 2007 ApJ, 663, 1187
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spectral templatemeasurement of spectral features
Eric Y. Hsiao
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reduction of systematic errors
Eric Y. Hsiao
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principal component analysis
PCA reduces multi-dimensional data into principal components
first component is the vector pointing toward the direction of the highest variance in the multi-dimensional data space
rest of the components are orthogonal vectors ranked by their variances
Eric Y. Hsiao
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spectroscopic sequence (V band)
Eric Y. Hsiao
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spectroscopic sequence (I band)
Eric Y. Hsiao
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spectroscopic sequence (I band)
Eric Y. Hsiao
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spectroscopic sequence (I band)
Eric Y. Hsiao
2000cx
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spectroscopic sequence (I band)
Eric Y. Hsiao
1999aa
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effect of epoch and stretch
Eric Y. Hsiao
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k-correction errors
Eric Y. Hsiao
k-correction errors Dmag Dflux
broadband color 10-1 10-1
spectral features 10-2 10-2
spectroscopic sequence 10-3 10-3
bandpass uncertainty 10-2~10-3 10-2~10-3
evolution small?