scholarly journals The Effect of a Coronal Expansion on the Computation of an Electron Temperature from Emission-Line Intensities.

1964 ◽  
Vol 139 ◽  
pp. 935 ◽  
Author(s):  
Werner M. Neupert
Keyword(s):  
Emission Line ◽  
Electron Temperature ◽  
Line Intensities

scholarly journals The SAMI Galaxy Survey: reconciling strong emission line metallicity diagnostics using metallicity gradients

2021 ◽  
Vol 502 (3) ◽  
pp. 3357-3373
Author(s):  
Henry Poetrodjojo ◽  
Brent Groves ◽  
Lisa J Kewley ◽  
Sarah M Sweet ◽  
Sebastian F Sanchez ◽  
...  
Keyword(s):  
Emission Line ◽  
Electron Temperature ◽  
Gas Phase ◽  
Mass Range ◽  
Accurate Method ◽  
Emission Lines ◽  
Mass Relation ◽  
Strong Emission ◽  
Data Release ◽  
Accurate Comparison

ABSTRACT We measure the gas-phase metallicity gradients of 248 galaxies selected from Data Release 2 of the SAMI Galaxy Survey. We demonstrate that there are large systematic discrepancies between the metallicity gradients derived using common strong emission line metallicity diagnostics. We determine which pairs of diagnostics have Spearman’s rank coefficients greater than 0.6 and provide linear conversions to allow the accurate comparison of metallicity gradients derived using different strong emission line diagnostics. For galaxies within the mass range 8.5 < log (M/M⊙) < 11.0, we find discrepancies of up to 0.11 dex/Re between seven popular diagnostics in the metallicity gradient–mass relation. We find a suggestion of a break in the metallicity gradient–mass relation, where the slope shifts from negative to positive, occurs between 9.5 < log (M/M⊙) < 10.5 for the seven chosen diagnostics. Applying our conversions to the metallicity gradient–mass relation, we reduce the maximum dispersion from 0.11 dex/Re to 0.02 dex/Re. These conversions provide the most accurate method of converting metallicity gradients when key emission lines are unavailable. We find that diagnostics that share common sets of emission line ratios agree best, and that diagnostics calibrated through the electron temperature provide more consistent results compared to those calibrated through photoionization models.

scholarly journals Temperature and Lifetime Measurements in the SSX Wind Tunnel

Plasma ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 229-241 ◽  
Author(s):  
Manjit Kaur ◽  
Kaitlin Gelber ◽  
Adam Light ◽  
Michael Brown
Keyword(s):  
Simple Model ◽  
Wind Tunnel ◽  
Electron Temperature ◽  
Langmuir Probe ◽  
Vacuum Ultraviolet ◽  
Lifetime Measurements ◽  
Line Intensities ◽  
Thermal Equilibration ◽  
Local Measurements ◽  
Doppler Spectroscopy

We describe ion and electron temperature measurements in the Swarthmore Spheromak Experiment (SSX) MHD wind tunnel with the goal of understanding limitations on the lifetime of our Taylor-state plasma. A simple model based on the equilibrium eigenvalue and Spitzer resistivity predicted the lifetime satisfactorily during the first phase of the plasma evolution. We measured an average T e along a chord by taking the ratio of the C I I I 97.7 nm to C I V 155 nm line intensities using a vacuum ultraviolet (VUV) monochromator. We also recorded local measurements of T e and n e using a double Langmuir probe in order to inform our interpretation of the VUV data. Our results indicated that the plasma decayed inductively during a large part of the evolution. Ion Doppler spectroscopy measurements suggested that ions cooled more slowly than would be expected from thermal equilibration with the electrons, which maintained a constant temperature throughout the lifetime of the plasma.

scholarly journals IUE Spectra of The by Dra/Flare Star AU Mic

1983 ◽  
Vol 71 ◽  
pp. 249-250
Author(s):  
C.J. Butler ◽  
A.D. Andrews ◽  
J.G. Doyle ◽  
P.B. Byrne ◽  
J.L. Linsky ◽  
...  
Keyword(s):  
Light Curve ◽  
Emission Line ◽  
Flare Star ◽  
Emission Lines ◽  
Spectral Variation ◽  
Strong Emission ◽  
Line Intensities ◽  
The Mean ◽  
Phase Interval

A coordinated series of ground-based optical and IUE observations of BY Dra variables was undertaken to follow the spectral variation of these stars over one cycle. In the first series 20 LWR and 19 SWP trailed spectra were taken of AU Mic over a three day period 4-6 August 1980 .In Figure 1 we show the mean integrated fluxes for the strong emission lines in the SWP spectra of AU Mic over the observed phase interval of 0.14 to 0.8 together with an approximate V light curve determined by the FES on IUE. From comparison of the emission line intensities and FES magnitudes in Figure 1 several points emerge.

Theoretical Helium i Emission-Line Intensities for Quiescent Prominences

1974 ◽  
Vol 192 ◽  
pp. 181 ◽  
Author(s):  
J. N. Heasley ◽  
Dimitri Mihalas ◽  
A. I. Poland
Keyword(s):  
Emission Line ◽  
Line Intensities

scholarly journals Spotty appearance of the solar disk as inferred from the comparaison between EUV and radio intensities

1965 ◽  
Vol 23 ◽  
pp. 109-114
Author(s):  
Z. Suemoto ◽  
F. Moriyama
Keyword(s):  
Electron Temperature ◽  
Transition Layer ◽  
Solar Disk ◽  
Sunspot Minimum ◽  
Line Intensities ◽  
Inhomogeneous Model ◽  
First Approximation

This is a revised version of the work reported to the COSPAR Symposium of 1962. In the first place, the basic components of the radio intensities ranging from 1000 MHz to 9400 MHz derived by H. Tanaka were used to establish the relation between the electron temperature and integrated number of electrons for 1960 and 1961 flights. The result justifies our former assumption that the radio intensities with which the EUV line intensities from the transition layer are to be compared should, as a first approximation, be very close to those at sunspot minimum.In the second place, the integrated numbers of electrons from the EUV line intensities were derived based on the same data as were used by Pottasch. This is to eliminate any arbitrariness in adopting parameters which are still uncertain.The result is that we still have a large amount of disagreement between the two sets of intensities in the sense that EUV line intensities are at least ten times stronger as might be inferred from the radio intensities. If one assumes an inhomogeneous model in which the solar disk is bright only in patches covering about 0.15 of its total area, the discrepancy would be eliminated.

Electron temperature and density sensitive X-ray emission line ratios for CI XVI

1993 ◽  
Vol 47 (2) ◽  
pp. 169-174 ◽  
Author(s):  
I H Coffey ◽  
F P Keenan ◽  
C E McAdam ◽  
R Barnsley ◽  
W J Dickson ◽  
...  
Keyword(s):  
Emission Line ◽  
Electron Temperature ◽  
X Ray

Transition probabilities for lines arising from the 3d4 4p configuration of Cr(II)

1994 ◽  
Vol 72 (1-2) ◽  
pp. 57-60 ◽  
Author(s):  
A. M. Gonzalez ◽  
M. Ortiz ◽  
J. Campos
Keyword(s):  
Experimental Data ◽  
Emission Line ◽  
Sum Rules ◽  
Transition Probabilities ◽  
Line Strength ◽  
Line Intensities ◽  
Cr Content ◽  
Absolute Scale ◽  
Relative Transition ◽  
Thin Plasma

Relative transition probabilities for 43 lines arising from the 3d4 4p configuration of Cr(II) with cores 3d4 (5D), 3d4 (3P), and 3d4 (3H) were determined from measurements of emission-line intensities in a laser produced plasma. This experiment was carried out with Al–Cr alloys with a Cr content of about 0.1%, in order to have an optically thin plasma. Transition probabilities were placed on an absolute scale by using, where possible, accurate experimental lifetimes from the literature and line-strength sum rules. Comparison of the present results with the available theoretical and experimental data are made.

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