Absolute fluxes, equivalent width and centre-to-limb profiles of the solar Mg II resonance lines (I).
Abstract
For the average quiet Sun we derive from high resolution Fabry Perot-echelle spectrograms profiles of the Mg II resonance lines in the wavelength region 2760 Å ≲ λ ≲ 2820 Å for the radial positions 1.0 ≧ = μ ≧ 0.995, 0.60±0.06 and 0.43±0.10. The profile of a plage region near the disc centre is also presented.
From the absolute flux calibrated observations of Kachalov and Jakovleva (1962), and Tousey et al. (1974), we derive the Mg II flux profile in the wavelength region 2660 Å ≲ λ ≲ 2940 Å. The Minnaert-Houtgast method is applied to the far wings of this profile in order to determine the undisturbed continuum level. Related to this continuum the equivalent width of the Mg II resonance lines is 83 Å. For the region 2770 Å ≲ λ ≲ 2820 Å a wavelength averaged limb darkening curve is derived. The Mg II profiles are calibrated using a combination of this limb darkening curve and the low spectral resolution flux profile. Our profile for the disc centre agrees in shape and absolute intensity with Kohl and Parkinson's (1976) recent observation. In the Appendix we generalize the Minnaert-Houtgast method for a blend of two strong multiplet lines and a linear variation of the continuum intensity.- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 1980
- Bibcode:
- 1980A&A....90..224G
- Keywords:
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- Line Spectra;
- Magnesium;
- Solar Limb;
- Solar Spectra;
- Spectral Line Width;
- Absorption Spectra;
- Interferometry;
- Resonance;
- Rocket Sounding;
- Spectrographs;
- Stellar Spectra;
- Solar Physics;
- Limb Darkening:Sun;
- Line Profiles:Solar Spectrum