scholarly journals Interpretation of Quiescent Behavior of Iron K-alpha (Fe Kα) Emission Line from Sigma Gem

2020 ◽  
Vol 7 (1) ◽  
pp. 15
Author(s):  
Ogbodo Osondu Vivian ◽  
Chima Abraham Iheanyichukwu ◽  
Onyia Augustine Ike
Keyword(s):  
Emission Line

FeXIV Line Emission Polarization of the July 11, 1991 Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 541-547
Author(s):  
J. Sýkora ◽  
J. Rybák ◽  
P. Ambrož
Keyword(s):  
High Resolution ◽  
Solar Corona ◽  
Emission Line ◽  
Solar Eclipse ◽  
White Light ◽  
Preliminary Analysis ◽  
Line Emission ◽  
Total Solar Eclipse ◽  
Degree Of Polarization ◽  
High Resolution Images

AbstractHigh resolution images, obtained during July 11, 1991 total solar eclipse, allowed us to estimate the degree of solar corona polarization in the light of FeXIV 530.3 nm emission line and in the white light, as well. Very preliminary analysis reveals remarkable differences in the degree of polarization for both sets of data, particularly as for level of polarization and its distribution around the Sun’s limb.

Structuring, Motions and Shapes of Corona Emission Line Profiles

1994 ◽  
Vol 144 ◽  
pp. 421-426
Author(s):  
N. F. Tyagun
Keyword(s):  
Emission Line ◽  
Filling Factor ◽  
Direct Relationship ◽  
Coronal Plasma ◽  
Line Of Sight ◽  
Line Profiles ◽  
The Difference ◽  
Yellow Line ◽  
Red Line

AbstractThe interrelationship of half-widths and intensities for the red, green and yellow lines is considered. This is a direct relationship for the green and yellow line and an inverse one for the red line. The difference in the relationships of half-widths and intensities for different lines appears to be due to substantially dissimilar structuring and to a set of line-of-sight motions in ”hot“ and ”cold“ corona regions.When diagnosing the coronal plasma, one cannot neglect the filling factor - each line has such a factor of its own.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

THEORETICAL ELECTRON DENSITY AND TEMPERATURE SENSITIVE EMISSION LINE RATIOS FOR HELIUM-LIKE Si XIII COMPARED TO DITE TOKAMAK OBSERVATIONS

1989 ◽  
Vol 50 (C1) ◽  
pp. C1-559-C1-564
Author(s):  
F. P. KEENAN ◽  
R. BARNSLEY ◽  
J. DUNN ◽  
K. D. EVANS ◽  
S. M. McCANN ◽  
...  
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
Temperature Sensitive ◽  
Electron Density And Temperature

Laser optoacoustic detection of trace concentration levels of ethylene, vinylchloride, and styrene in the atmosphere

1989 ◽  
Vol 54 (10) ◽  
pp. 2667-2673 ◽  
Author(s):  
Vojtěch Steiner ◽  
Pavel Engst ◽  
Zdeněk Zelinger ◽  
Milan Horák
Keyword(s):  
Detection Limit ◽  
Emission Line ◽  
Laser Line ◽  
Laser Source ◽  
Trace Concentration ◽  
Selective Determination ◽  
Hygienic Standard ◽  
Trace Concentrations ◽  
Concentration Levels

The optoacoustic analyzer with a tunable CO2 laser source employed in the present work permits a selective determination of ethylene in trace concentrations higher than 5 ppb (=detection limit for the 10P(14) emission line of the CO2 laser, ν = 949.5 cm-1) and of vinylchloride higher than 42 ppb (= detection limit for the 10P(22) CO2 laser line, ν= 942.4 cm-1). this method covers for both compounds the concentration range corresponding to the hygienic standard. It can be also used for the determination of styrene vapour with concentrations higher than 1.5 ppm.

Wind Inhomogeneities in Wolf-Rayet Stars. III. Unusual Emission-Line Profile Variations in [FORMULA][F]γ[SUP]2[/SUP][/F][/FORMULA] Velorum

1999 ◽  
Vol 117 (3) ◽  
pp. 1441-1453 ◽  
Author(s):  
Sébastien Lépine ◽  
Thomas Eversberg ◽  
Anthony F. J. Moffat
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Emission Line Profile

Emission-Line Diagnostics of T Tauri Magnetospheric Accretion. I. Line Profile Observations

1998 ◽  
Vol 116 (1) ◽  
pp. 455-468 ◽  
Author(s):  
James Muzerolle ◽  
Lee Hartmann ◽  
Nuria Calvet
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
T Tauri ◽  
Magnetospheric Accretion

Wind Inhomogeneities in Wolf‐Rayet Stars. II. Investigation of Emission‐Line Profile Variations

1999 ◽  
Vol 514 (2) ◽  
pp. 909-931 ◽  
Author(s):  
Sebastien Lepine ◽  
Anthony F. J. Moffat
Keyword(s):  
Emission Line ◽  
Line Profile ◽  
Emission Line Profile

scholarly journals Gaia-assisted discovery of a detached low-ionisation BAL quasar with very large ejection velocities

2020 ◽  
Vol 634 ◽  
pp. A111 ◽  
Author(s):  
J. P. U. Fynbo ◽  
P. Møller ◽  
K. E. Heintz ◽  
J. N. Burchett ◽  
L. Christensen ◽  
...  
Keyword(s):  
Emission Line ◽  
Absorption Line ◽  
Emission Lines ◽  
Broad Absorption ◽  
Broad Absorption Line ◽  
Red Edge ◽  
First Case ◽  
Bl Lac ◽  
Spatially Extended ◽  
Extended Emission

We report on the discovery of a peculiar broad absorption line (BAL) quasar identified in our Gaia-assisted survey of red quasars. The systemic redshift of this quasar was difficult to establish because of the absence of conspicuous emission lines. Based on deep and broad BAL troughs of at least Si IV, C IV, and Al III, a redshift of z = 2.41 was established under the assumption that the systemic redshift can be inferred from the red edge of the BAL troughs. However, we observe a weak and spatially extended emission line at 4450 Å that is most likely due to Lyman-α emission, which implies a systemic redshift of z = 2.66 if correctly identified. There is also evidence for the onset of Lyman-α forest absorption bluewards of 4450 Å and evidence for Hα emission in the K band consistent with a systemic redshift of z = 2.66. If this redshift is correct, the quasar is an extreme example of a detached low-ionisation BAL quasar. The BALs must originate from material moving with very large velocities ranging from 22 000 km s−1 to 40 000 km s−1. To our knowledge, this is the first case of a systemic-redshift measurement based on extended Lyman-α emission for a BAL quasar. This method could also be useful in cases of sufficiently distant BL Lac quasars without systemic-redshift information.

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.

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