Abnormal scattering event in the direction to the pulsar B0834+06

2020 ◽  
Vol 496 (4) ◽  
pp. 5149-5159
Author(s):  
T V Smirnova ◽  
V I Shishov ◽  
A S Andrianov ◽  
M S Burgin ◽  
E N Fadeev ◽  
...  
Keyword(s):  
Strong Influence ◽  
Axial Ratio ◽  
Major Axis ◽  
Position Angle ◽  
Small Scale ◽  
High Electron ◽  
High Electron Density ◽  
Vlbi Observations ◽  
Scattering Time ◽  
Very High

ABSTRACT Analysis of Space-VLBI observations of the pulsar B0834+06 conducted with RadioAstron at 324 MHz shows that in some cases one of the scattering screens could be located very close to the pulsar (about 10 pc from the pulsar), and it has a strong influence on the secondary spectra. For this case, the vertices of inverted arcs are aligned along the main parabolic arc and their width is inversely proportional to the scattering time. The shape of the main arc is determined by another scattering screen that is located at a distance of about 210 pc from the pulsar. The position of this screen is observed to be stable during 19 yr and its spatial scale is larger than 5.6 × 1015 cm. We found that the scattering disc may be approximated by an ellipse with a 2.5 axial ratio and with the position angle of the major axis of about −8○. A small-scale structure with a size of 0.1 au located at the close to observer screen and very high electron density of tens to a few thousand cm−3 for different models can be responsible for arclets in a secondary spectra. Additionally, angular refraction exists in the direction towards the pulsar. That suggests the presence of the cosmic prism. We have estimated the angle of refraction to be θref > 2 mas and the distance from prism to the observer D < 160 pc.

scholarly journals The Orientation of Galaxies in Superclusters

1988 ◽  
Vol 130 ◽  
pp. 239-241
Author(s):  
Piotr Flin
Keyword(s):  
Positive Result ◽  
Spatial Orientation ◽  
Axial Ratio ◽  
Major Axis ◽  
Position Angle ◽  
Main Plane ◽  
Local Supercluster ◽  
The Galaxy ◽  
Spatial Geometry

The alignment of galaxies with the main plane of supercluster can contribute to recovering information on the structure origin. The positive result of the preliminary search for galaxy alignment in the Local Supercluster /Flin and Godlowski 1986, hereafter FG/ have stimulated further studies. Following Jaaniste and Saar /1977/, the both parameters, the position angle of the galaxy major axis p and the axial ratio b/a of the galaxy image, were used for the better determination of the actual spatial orientation of the galaxy disc. This approach also permit to consider “face-on” objects, whose discounting leads to obvious incompleteness of the analysed data. Each galaxy has two possible orientations and both were taken into account during calculations. The analysis is perfomed by transforming position angle p and coordinates α, δ of galaxies expressed in the equatorial coordinates into coordinate system connected with each parent supercluster separately, which gives parameters P, l and b respectively. The main supercluster plane should be determined, which resticts the present study to the three superclusters with a known spatial geometry, i.e. LSC /Tully 1982/, Perseus and Coma/A1367 /Chincarini et al. 1983/.

Production of very high electron density assisted by lasers

1989 ◽  
Vol 24 (6) ◽  
pp. 1049-1052 ◽  
Author(s):  
J.P. Girardeau-Montaut ◽  
C. Girardeau-Montaut ◽  
R. Dei-Cas
Keyword(s):  
Electron Density ◽  
High Electron ◽  
High Electron Density ◽  
Very High

scholarly journals Resolving the Nucleus of Centaurus A at Mid-Infrared Wavelengths

2010 ◽  
Vol 27 (4) ◽  
pp. 490-495 ◽  
Author(s):  
Leonard Burtscher ◽  
Klaus Meisenheimer ◽  
Walter Jaffe ◽  
Konrad R. W. Tristram ◽  
Huub J. A. Rottgering
Keyword(s):  
Dust Emission ◽  
Galactic Nuclei ◽  
Major Axis ◽  
Seyfert Galaxies ◽  
Position Angle ◽  
Small Scale ◽  
Mid Infrared ◽  
Very Large Telescope ◽  
Infrared Wavelengths ◽  
Centaurus A

AbstractWe have observed Centaurus A with the Mid-Infrared Interferometric Instrument (MIDI) at the Very Large Telescope Interferometer at resolutions of 7–15 mas (at 12.5 μm) and filled gaps in the (u, v) coverage in comparison to earlier measurements. We are now able to describe the nuclear emission in terms of geometric components and derive their parameters by fitting models to the interferometric data. With simple geometrical models, the best fit is achieved for an elongated disk with flat intensity profile with diameter 76 ± 9 × 35 ± 2 mas (1.41 ± 0.17 × 0.65 ± 0.03 pc) whose major axis is oriented at a position angle (PA) of 10.1 ± 2.2° east of north. A point source contributes 47 ± 11% of the nuclear emission at 12.5 μm. There is also evidence that neither such a uniform nor a Gaussian disk are good fits to the data. This indicates that we are resolving more complicated small-scale structure in active galactic nuclei with MIDI, as has been seen in Seyfert galaxies previously observed with MIDI. The PA and inferred inclination i = of the dust emission are compared with observations of gas and dust at larger scales.

DEVELOPMENT OF A LAND DEGRADATION ASSESSMENT MODEL BASED ON FIELD INDICATORS ASSESSMENT AND PREDICTION METHODS IN WAI SARI, SUB-WATERSHED KAIRATU DISTRICT, WESTERN SERAM REGENCY, MALUKU PROVINCE, INDONESIA

2019 ◽  
Vol 2 (1) ◽  
pp. 071-084
Author(s):  
Silwanus M. Talakua ◽  
Rafael M. Osok
Keyword(s):  
Land Degradation ◽  
Soil Loss ◽  
Assessment Model ◽  
Small Scale ◽  
Small Islands ◽  
Topographic Map ◽  
Field Assessment ◽  
Field Indicators ◽  
Degradation Measurement ◽  
Very High

The study was conducted in Wai Sari sub-watershed, Western Seram Regency Maluku to develop an accurate land degradation assessment model for tropical small islands. The Stocking’s field land degradation measurement and RUSLE methods were applied to estimate soil loss by erosion and the results of both methods were statistically tested in order to obtain a correction factor. Field indicators and prediction data were measured on 95 slope units derived from the topographic map. The rates of soil loss were calculated according to both methods, and the results were used to classify the degree of land degradation. The results show that the degree of land degradation based on the field assessment ranges from none-slight (4.04 - 17.565 t/ha/yr) to very high (235.44 - 404.00 t/ha/yr), while the RUSLE method ranges from none-slight (0.04-4.59 t/ha/yr) to very high 203.90 - 518.13 t/ha/yr.  However, the RUSLE method shows much higher in average soil loss (133.4 t/ha/yr) than the field assessment (33.9 t/ha/yr). The best regression equation of  logD/RP = - 0.594 + 1.0 logK + 1.0 logLS + 1.0 logC or D = 0.2547xRxKxLSx CxP was found to be a more suitable land degradation assessment  model for a small-scale catchment area in the tropical small islands.

Unusually high electron density in an intermolecular non-bonding region: Role of metal substrate

2017 ◽  
Vol 28 (4) ◽  
pp. 759-764 ◽  
Author(s):  
Chen-Guang Wang ◽  
Zhi-Hai Cheng ◽  
Xiao-Hui Qiu ◽  
Wei Ji
Keyword(s):  
Electron Density ◽  
Metal Substrate ◽  
High Electron ◽  
High Electron Density

Partially planar BP3with high electron mobility as a phosphorene analog

2017 ◽  
Vol 5 (43) ◽  
pp. 11267-11274 ◽  
Author(s):  
Fazel Shojaei ◽  
Hong Seok Kang
Keyword(s):  
Electron Mobility ◽  
High Electron ◽  
Two Dimensional ◽  
High Electron Mobility ◽  
Stacking Pattern ◽  
Very High ◽  
Bilayer Formation

We propose a two-dimensional BP3crystal with a very high electron mobility of 4.6 × 104cm2V−1s−1. Bilayer formation, specifically stacking pattern AA, results in an even higher electron mobility of ∼3.7 × 105cm2V−1s−1, which is ∼2500 times larger than that of an α phosphorene bilayer.

scholarly journals Very high electron temperatures in the daytime F region at Sondrestrom

1984 ◽  
Vol 11 (9) ◽  
pp. 919-922 ◽  
Author(s):  
Wlodek Kofman ◽  
Vincent B. Wickwar
Keyword(s):  
High Electron ◽  
F Region ◽  
Very High
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