Complex Variations in the Line-Intensity Ratio of Coronal Emission Lines with Height above the Limb

2004 ◽  
Vol 617 (1) ◽  
pp. L81-L84 ◽  
Author(s):  
Jagdev Singh ◽  
Takashi Sakurai ◽  
Kiyoshi Ichimoto ◽  
Tetsuya Watanabe
Keyword(s):  
Line Intensity ◽  
Intensity Ratio ◽  
Emission Lines ◽  
Coronal Emission ◽  
Line Intensity Ratio

On green-to-red line intensity ratio in the solar corona

Solar Physics ◽  
1976 ◽  
Vol 46 (1) ◽  
pp. 183-184 ◽  
Author(s):  
S. Chandra ◽  
U. Narain
Keyword(s):  
Solar Corona ◽  
Line Intensity ◽  
Intensity Ratio ◽  
Line Intensity Ratio ◽  
Red Line

scholarly journals Comparing the emission spectra of U and Th hollow cathode lamps and a new U line list

2018 ◽  
Vol 618 ◽  
pp. A118 ◽  
Author(s):  
L. F. Sarmiento ◽  
A. Reiners ◽  
P. Huke ◽  
F. F. Bauer ◽  
E. W. Guenter ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Hollow Cathode ◽  
Line Intensity ◽  
Line Strength ◽  
Emission Spectra ◽  
Emission Lines ◽  
Line List ◽  
Line Intensity Ratio ◽  
Suitable Combination

Context. Thorium hollow cathode lamps (HCLs) are used as frequency calibrators for many high resolution astronomical spectrographs, some of which aim for Doppler precision at the 1 m s−1 level. Aims. We aim to determine the most suitable combination of elements (Th or U, Ar or Ne) for wavelength calibration of astronomical spectrographs, to characterize differences between similar HCLs, and to provide a new U line list. Methods. We record high resolution spectra of different HCLs using a Fourier transform spectrograph: (i) U–Ne, U–Ar, Th–Ne, and Th–Ar lamps in the spectral range from 500 to 1000 nm and U–Ne and U–Ar from 1000 to 1700 nm; (ii) we systematically compare the number of emission lines and the line intensity ratio for a set of 12 U–Ne HCLs; and (iii) we record a master spectrum of U–Ne to create a new U line list. Results. Uranium lamps show more lines suitable for calibration than Th lamps from 500 to 1000 nm. The filling gas of the lamps significantly affects their performance because Ar and Ne lines contaminate different spectral regions. We find differences (up to 88%) in the line intensity of U lines in different lamps from the same batch. We find 8239 isolated lines between 500 and 1700 nm that we attribute to U, 3379 of which were not contained in earlier line lists. Conclusions. We suggest using a combination of U–Ne and U–Ar lamps to wavelength-calibrate astronomical spectrographs up to 1 μm. From 1 to 1.7 μm, U–Ne shows better properties. The differences in line strength between different HCLs underline the importance of characterizing HCLs in the laboratory. The new 3379 U lines can significantly improve the radial velocity precision of astronomical spectrographs.

Detection of Singly Ionized Oxygen Around Jupiter

Science ◽  
1979 ◽  
Vol 205 (4403) ◽  
pp. 297-298 ◽  
Author(s):  
C. B. PILCHER ◽  
J. S. MORGAN
Keyword(s):  
Line Intensity ◽  
Intensity Ratio ◽  
Magnetic Equator ◽  
Jovian Magnetosphere ◽  
Line Intensity Ratio ◽  
Sulfur Emission ◽  
Plasma Characteristics

Forbidden emission from singly ionized oxygen at wavelengths of 3726 and 3729 angstroms has been detected in the inner Jovian magnetosphere. The emission is present between ∼4 and ∼7 to 8 Jovian radii from the planet and appears concentrated in the magnetic equator. The line intensity ratio indicates the same plasma characteristics as those derived from observations of forbidden sulfur emission.

scholarly journals X-ray Lines From Mg VIII and Si X Ions and Their Diagnostic Use

1990 ◽  
Vol 115 ◽  
pp. 40-43
Author(s):  
Bhola N. Dwivedi
Keyword(s):  
Electron Density ◽  
Line Intensity ◽  
Coronal Holes ◽  
Emission Lines ◽  
X Ray ◽  
Quiet Sun ◽  
Diagnostic Use ◽  
Line Intensity Ratio ◽  
Theoretical Line ◽  
Intensity Ratios

AbstractThe solar X-ray emission lines from Mg VIII and Si X ions have been studied. The variation of theoretical line intensity ratio I(λ 75.03)/I(λ 74.86) from Mg VIII and I(λ 50.69)/I(λ 50.52) from Si X as a function of electron density is found to be good density monitors of the emitting regions of solar plasma. The computed values of line intensity from these ions based on Kopp and Orrall model have been used to derive electron density of the quiet Sun and coronal holes. The electron densities of 109 cm-3 and 4.6 × 108 cm-3 are estimated at the electron temperatures of 8 x 105 K and 1.6 x 106 K for the quiet Sun whereas the respective values of 5.4 x 108 cm-3 and 1.7 x 108 cm-3 are obtained for the coronal holes. The line intensity ratios studied here are independent of temperature variation and are therefore excellent candidates for electron density diagnostics. However, observational data with improved spectral resolution is needed for using X-ray line pairs studied for their diagnostic use.

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