Circular polarization measurement in millimeter-wavelength spectral-line VLBI observations

AbstractWe present here 3 epochs of 3 and 7 millimeter wavelength VLBI observations and 2 epochs of lower frequency VLBA imaging of the gamma-ray blazar NRAO 530. These observations document the evolution of the parsec scale jet in this source during the brightest flare in 3 decades. New jet components were created during the flare and are probably related to an increase in gamma-ray activity. The components travel at superluminal velocities, further confirming the connection between superluminal sources and gamma-ray blazars. The rapid evolution of the source makes tracking of components difficult. It appears that either components significantly decelerate or that there is rapid cooling and acceleration of elections. We may be identifying structure due to standing shocks. The jet is bent on all scales between 100 μarcsec to 10 arcsec. The results indicate the ability of 3 mm wavelength imaging to probe the nuclei of blazars rapidly and reliably.

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Circular Polarization Measurement Using a Tunable Lithium Niobate Fabry-Perot Filter

Solar Polarization - Astrophysics and Space Science Library ◽

10.1007/978-94-015-9329-8_27 ◽

1999 ◽

pp. 321-324

Author(s):

S. K. Mathew ◽

A. Bhatnagar ◽

C. Debi Prasad ◽

A. Ambastha

Keyword(s):

Lithium Niobate ◽

Circular Polarization ◽

Polarization Measurement ◽

Fabry Perot

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

Symposium - International Astronomical Union ◽

10.1017/s0074180900078165 ◽

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.

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Circular Polarization Measurement of Gamma Rays Following Beta Decay ofAl24andNa24to Determine the Meson Exchange Effect

Physical Review ◽

10.1103/physrev.134.b481 ◽

1964 ◽

Vol 134 (3B) ◽

pp. B481-B484 ◽

Cited By ~ 7

Author(s):

S. D. Bloom ◽

L. G. Mann ◽

R. Polichar ◽

J. R. Richardson ◽

A. Scott

Keyword(s):

Circular Polarization ◽

Beta Decay ◽

Gamma Rays ◽

Polarization Measurement ◽

Meson Exchange ◽

Exchange Effect

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Maser observations with new instruments

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312007557 ◽

2012 ◽

Vol 8 (S287) ◽

pp. 477-482

Author(s):

Alwyn Wootten

Keyword(s):

Spectral Line ◽

North American ◽

Large Array ◽

Very Large Array ◽

Millimeter Wavelength ◽

The North ◽

The Universe ◽

New Instruments

AbstractThe Atacama Large Millimeter/submillimeter Array (ALMA)‡, and the Jansky Very Large Array (JVLA) have recently begun probing the Universe. Both provide the largest collecting area available at locations on a high dry site, endowing them with unparalleled potential for sensitive spectral line observations. Over the next few years, these telescopes will be joined by other telescopes to provide advances in maser science, including NOEMA and the LMT. Other instruments of note for maser science which may commence construction include the North American Array, the CCAT, and an enlarged worldwide VLB network outfitted to operate into the millimeter wavelength regime.

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Magnetic Fields in Molecular Cloud Cores

Symposium - International Astronomical Union ◽

10.1017/s0074180900190254 ◽

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.

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