VLBI observations of 3C 345 and NRAO 512 in right and left circular polarization

1978 ◽  
Vol 220 ◽  
pp. L27
Author(s):  
C. R. Menyuk ◽  
I. I. Shapiro ◽  
J. J. Wittels ◽  
H. F. Hinteregger ◽  
C. A. Knight ◽  
...  
Keyword(s):  
Circular Polarization ◽  
Vlbi Observations ◽  
Left Circular Polarization

scholarly journals Method of Averaged Lagrangian for Precessional Rotation and Other Complementary Effects of Waves in Nonlinear Plasmas

1983 ◽  
Vol 36 (6) ◽  
pp. 867
Author(s):  
B Chakraborty ◽  
SN Paul
Keyword(s):  
Electromagnetic Wave ◽  
Circular Polarization ◽  
Wave Number ◽  
Mathematical Technique ◽  
Relativistic Plasmas ◽  
Left Circular Polarization ◽  
Nonlinear Modulation ◽  
The Right ◽  
Elliptically Polarized

The formalism of the averaged Lagrangian has been extended and developed to evaluate the intensitydependent precessional rotation and wave number shift of an elliptically polarized electromagnetic wave in unmagnetized cold relativistic plasmas; the results are identical to those of Arons and Max (1974) and others. Moreover, the expression for two intensity-induced nonlinear modulation frequencies for both the right and left circular polarization components of the wave have been derived. The mathematical technique developed here may be useful in the study of other types of nonlinearly evolved rotational corrections for motions in fluids, and so the possibilities of broadening the scope of this formalism are discussed.

scholarly journals 1038+528 A, B: Phase-Reference and Spectral-Index Maps

1984 ◽  
Vol 110 ◽  
pp. 247-248
Author(s):  
J. Marcaide ◽  
I. Shapiro ◽  
N. Cohen ◽  
B. Corey ◽  
W. Cotton ◽  
...  
Keyword(s):  
Circular Polarization ◽  
Spectral Index ◽  
Reference Point ◽  
Reference Points ◽  
Vlbi Observations ◽  
Structure Phase ◽  
Propagation Medium ◽  
Image Position ◽  
Index Maps

On 1981 March 17–18 we undertook MkIII VLBI observations of the quasars 1038+528 A, B (Owen et al. 1979; Owen et al. 1980) with an array of 7 telescopes operating simultaneously at λ3.6 and λ13 cm with right circular polarization reception at each wavelength. Because the sources are ~33″ apart they could be observed simultaneously at every telescope. Thus the corrupting contributions of the propagation medium and the instrumentation were approximately the same for each of the quasars, hence allowing us to calibrate the structure phase of B with respect to a reference point chosen in the map of A using the expression where φB and φA are the observed fringe phases, φGB and φGA are the geometric contribution with respect to the reference points chosen in each map and φSA is the structure phase contribution with respect to the reference point chosen in the A map.

scholarly journals Magnetic Fields in Molecular Cloud Cores

1990 ◽  
Vol 140 ◽  
pp. 291-292
Author(s):  
Z.P. Zhou ◽  
X.W. Zheng
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Circular Polarization ◽  
Molecular Cloud ◽  
Zeeman Splitting ◽  
Hii Regions ◽  
Observational Evidence ◽  
Hii Region ◽  
Vlbi Observations ◽  
Cloud Cores

Strong circular polarization of OH masers at 1665 and 1667 MHz lines has been observed towards the molecular cloud cores associated with HII regions. Magnetic field strengths of a few mG are derived from the Zeeman splitting of OH lines. For instance, a magnetic field of about 4 mG in the masing region of W3(OH) has been estimated by OH-line Zeeman splitting (Davies, 1974). VLBI observations show that the OH maser spots project onto or very close to the surface of associated compact HII regions (Reid et al., 1986). The observational evidence demonstrates that the scales of OH maser components surrounding a compact HII region (R ~ 1016 cm) are about 1014 cm in diameter with an amplification pathlength of ~1015 cm. Hence the magnetic fields determined by the Zeeman splitting of OH maser lines appear partly very close to the associated HII region. Elitzur (1979) has theoretically obtained similar results as above.

scholarly journals Direct discrimination of structured light by humans

2020 ◽  
Vol 117 (26) ◽  
pp. 14682-14687 ◽  
Author(s):  
Dusan Sarenac ◽  
Connor Kapahi ◽  
Andrew E. Silva ◽  
David G. Cory ◽  
Ivar Taminiau ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Circular Polarization ◽  
Success Probability ◽  
Direct Perception ◽  
Spin Orbit ◽  
Average Sensitivity ◽  
Spatial Modes ◽  
Direct Discrimination ◽  
Left Circular Polarization ◽  
Psychophysical Study

We predict and experimentally verify an entoptic phenomenon through which humans are able to perceive and discriminate optical spin–orbit states. Direct perception and discrimination of these particular states of light with polarization-coupled spatial modes is possible through the observation of distinct profiles induced by the interaction between polarization topologies and the radially symmetric dichroic elements that are centered on the foveola in the macula of the human eye. A psychophysical study was conducted where optical states with a superposition of right and left circular polarization coupled to two different orbital angular momentum (OAM) values (ℓ1andℓ2) were directed onto the retina of participants. The number of azimuthal fringes that a human sees when viewing the spin–orbit states is shown to be equal to the number (N) of radial lines in the corresponding polarization profile of the beam, whereN=|(ℓ1−ℓ2)−2|. The participants were able to correctly discriminate between two states carrying OAM=7and differentiated byN=5andN=9, with an average success probability of 77.6% (average sensitivityd′=1.7,t(9)=5.9,p=2×10−4). These results enable methods of robustly characterizing the structure of the macula, probing retina signaling pathways, and conducting experiments with human detectors and optical states with nonseparable modes.

scholarly journals VLBI Observations of M87

1982 ◽  
Vol 97 ◽  
pp. 293-294
Author(s):  
M. J. Reid ◽  
J.H.M.M. Schmitt ◽  
F. N. Owen ◽  
R. S. Booth ◽  
P. N. Wilkinson ◽  
...  
Keyword(s):  
Circular Polarization ◽  
Flux Density ◽  
Position Angle ◽  
Large Component ◽  
Vlbi Observations ◽  
Standard Techniques

On 1980 February 20 we conducted an 8-station intercontental VLBI experiment in order to study the nucleus and jet of M87 at 1666.6 MHz in right circular polarization. Our array was sensitive to structures from 0.001 to 0.1 arcsec. We made a hybrid map of the nucleus of M87, and also searched for compact structures within the knots of the jet. The map (Figure 1) shows that the nucleus of M87 contains a one-sided jet. This morphology is similar to that observed in many compact extragalactic sources. The position angle of the nuclear jet is 290.5 (±1) degrees, which precisely matches that of the 20 arcsec jet. No bending of the jet through an angle greater than about 2 degrees is observed. The nucleus also contains a large component (>0.1 arcsec) which is elongated along the same position angle as the jet and has a flux density of roughly 1 Jy. This component is fully resolved by the vast majority of our (u, v) points, and we could not map it with standard techniques.

scholarly journals Circular Polarization at 1665 and 1667 MHz Towards OH Masers in NGC 6334N, NGC 7538N, NGC 7538S, and G45.07+0.13

1988 ◽  
Vol 129 ◽  
pp. 263-264
Author(s):  
X. W. Zheng ◽  
J. M. Moran ◽  
M. J. Reid ◽  
M. H. Schneps ◽  
J. A. Garcia-Barreto ◽  
...  
Keyword(s):  
Circular Polarization ◽  
Left Circular Polarization ◽  
The Right ◽  
Maser Sources

VLBI OH maser observations simultaneously in right and left circular polarization at the 1665 and 1667 MHz transitions were conducted by taking advantage of the multichannel capability of the Mk III system. The OH maser maps of the right and left circular polarization at both transitions were obtained toward the OH maser sources NGC 6334N, NGC 7538N, NGC 7538S, and G45.07+0.13.

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