Page 28 - analysis-and-interpretation-of-astronomical-sp

Analysis and Interpretation of Astronomical Spectra 28

8.3 Relationship Between Original-Continuum and Pseudo-Continuum

The following diagram shows two identical sections of the same spectrum: on the left the
undisturbed original profile and on the right the recorded raw spectrum with the

pseudo-continuum It shows each an absorption and an emission line. Within this fic-

tional spectral section, the course of , and is assumed to run horizon-

tally.

I Original Recorded
Profile Profile
IEO

Or λ ΔIC IE

ICO IAO Ps λ

IC IA

λλ

The following relationships and its consequences can be derived:

 Due to the selective attenuation, at a certain wavelength , the continuum-intensity of
the recorded profile appears to be reduced by , compared with the original-

spectrum .

8.4 Attenuation of Absorption Lines , are at-

The continuum intensity and the penetration depth of the absorption line
tenuated equally proportional.

As an example the following graph shows the Sirius spectrum with the virtual original pro-
file and the recorded pseudo-continuum . The absorption lines always remain

proportionally and inseparably connected to the continuum. Therefore the -related

measurement categories – Peak Intensity , and Equivalent width – cannot be

changed by a simple division or multiplication by .