- K correction
K correction is a correction to an astronomical object's magnitude (or equivalently, its
flux ) that allows a measurement of a quantity of light from an object at aredshift "z" to be converted to an equivalent measurement in therest frame of the object. If one could measure all the light from an object at allwavelength s (a bolometric flux), a K correction would not be required. If one measures the light emitted in anemission line , a K-correction is not required. The need for a K-correction arises because an astronomical measurement through a single filter or a single bandpass only sees a fraction of the totalspectrum , redshifted into the frame of the observer. So if the observer wants to compare the measurements through a red filter of objects at different redshifts, the observer will have to apply estimates of the K corrections to these measurements to make a comparison.The exact nature of the calculation that needs to be applied in order to perform a K correction depends upon the type of filter used to make the observation and the shape of the object's spectrum.
The term K correction was coined by
Edwin Hubble , who arbitrarily chose to represent the reduction factor in magnitude due to this effect. [cite journal | title=Effects of Red Shifts on the Distribution of Nebulae | authorlink=Edwin Hubble | first=Edwin | last=Hubble | year=1936 | journal=Astrophysical Journal | volume=84 | pages=517–554]References
External links
* [http://www.ucolick.org/~cnaw/kcorr/kplot.html K Correction plots]
* [http://xxx.lanl.gov/abs/astro-ph/0210394 The K correction]
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