Lesson plan
K correction
K correction is a process for converting measurements of astronomical objects into their respective rest frames. The correction acts on that object's observed magnitude (or equivalently, its flux). Because astronomical observations often measure through a single filter or bandpass, observers only measure a fraction of the total spectrum, redshifted into the frame of the observer. For example, to compare measurements of stars at different redshifts viewed through a red filter, one must estimate K corrections to these measurements in order to make comparisons. If one could measure all wavelengths of light from an object (a bolometric flux), a K correction would not be required, nor would it be required if one could measure the light emitted in an emission line. Carl Wilhelm Wirtz (1918), who referred to the correction as a (German for "constant") – correction dealing with the effects of redshift of in his work on Nebula. The English-language claim for the origin of the term "K correction" is Edwin Hubble, who supposedly arbitrarily chose K to represent the reduction factor in magnitude due to this same effect and who may not have been aware of or given credit to the earlier work.…
Article summary
K correction is a process for converting measurements of astronomical objects into their respective rest frames. The correction acts on that object's observed magnitude (or equivalently, its flux). Because astronomical observations often measure through a single filter or bandpass, observers only measure a fraction of the total spectrum, redshifted into the frame of the observer. For example, to compare measurements of stars at different redshifts viewed through a red filter, one must estimate K corrections to these measurements in order to make comparisons. If one could measure all wavelengths of light from an object (a bolometric flux), a K correction would not be required, nor would it be required if one could measure the light emitted in an emission line. Carl Wilhelm Wirtz (1918), who referred to the correction as a (German for "constant") – correction dealing with the effects of redshift of in his work on Nebula. The English-language claim for the origin of the term "K correction" is Edwin Hubble, who supposedly arbitrarily chose K to represent the reduction factor in magnitude due to this same effect and who may not have been aware of or given credit to the earlier work.…
Key claims
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Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
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Key claims and bibliography are generated from the same tracked claims and sources as the article page.