On the Calculation of Equivalent Widths from SpectralLine Profiles.
Abstract
The determination of equivalent width from a line profile in terms of Hjerting functions requires knowledge of the scale factor = A /V, where AX is the displacement in wavelength from the line's center and V is the Hjerting function argument. Tables are given in Section II which will allow the determination of p for a profile Pk(AXk) evaluated only at three values of AX,. Necessary factors to compute the equivalent width, based on fitting a Hjerting function to these points, are also tabulated. More general numerical integration formulae for determining the equivalent width, based on Hjerting functions, are discussed in Section III, and the weights and divisions V, are tabulated As shown in Section IV, these formulae will give greater accuracy for fewer divisions than methods now in use. For computed profiles, this should effect a worthwhile reduction in computational effort.
 Publication:

The Astrophysical Journal
 Pub Date:
 February 1963
 DOI:
 10.1086/147522
 Bibcode:
 1963ApJ...137..470E