Remarks on statistical errors in equivalent widths

Klaus Vollmann and Thomas Eversberg

Schnörringen Telescope Science Institute (STScI), Ringweg 7, 51545 Waldbröl, Germany

Equivalent width measurements for rapid line variability in atomic spectral lines are degraded by increasing error bars with shorter exposure times. We derive an expression for the error of the line equivalent width $\sigma(W_\lambda)$ with respect to pure photon noise statistics and provide a correction value for previous calculations.

Reference: Astronomical Notes
Status: Manuscript has been accepted