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I have the following equation used to calculate line flux from equivalent width.

$F_{line}=EW \times F_{cont}$

If $EW$, the equivalent width of a line is in Angstroms, and $F_{cont}$, the continuum flux density unit is in $ erg\hspace{1pt} s^{-1} cm^{-2}{Hz}^{-1}$, then what would be the units of $F_{line}$? From the equation the units should be $erg\hspace{1pt} s^{-1} cm^{-2}{Hz}^{-1}A$ but the line flux units are $erg\hspace{1pt} s^{-1} cm^{-2}A^{-1}$.

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The equation is dimensionally incorrect, or at least the two "fluxes", represented by $F$ cannot have the same units.

Equivalent width is in units of wavelength, thus the units of $F_{\rm line}$ are the units of $F_{\rm cont}$ multiplied by a wavelength.

For example, $F_{\rm cont}$ could be in erg cm$^{-2}$ per Angstrom, the equivalent width would be in Angstroms and $F_{\rm line}$ would be in erg cm$^{-2}$.

If $F_{\rm cont}$ is not expressed per unit of wavelength, then it needs to be converted to be so before multiplying it by equivalent width.

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