• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.345-353
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• 2013

A W-band Orthomode Transducer (OMT) has been developed for Korean VLBI Network (KVN) polarization observation. The OMT design was based on E-plane split-block technique using septum structure. 3-dimensional electromagnetic simulation was fully employed to optimize the performance of the OMT. Measurements of the fabricated OMT show that the return losses for the vertically and horizontally polarized modes are better than -20 dB across 80 ~ 108 GHz and the insertion losses for the both modes are less than 0.47 dB. The cross-polarization level of the OMT is less than -30 dB. The bandwidth of the developed OMT is estimated as around 30%.

• Journal of Astronomy and Space Sciences
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• v.38 no.4
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• pp.193-202
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• 2021

We present analysis results of Korean VLBI Network (KVN) four-band data for the highly variable blazar 3C 279. We measured the 22, 43, 86, and 129 GHz flux densities and spectral indices of the source using contemporaneous data taken over 5.6 years. We used the discrete correlation function to investigate correlations between the radio emission properties and those measured in the optical (2 × 10¹⁴ - 1.5 × 10¹⁵ Hz), X-ray (0.3-10 keV), and gamma-ray (0.1-300 GeV) bands. We found a significant correlation between the radio spectral index and gamma-ray flux without a time delay and interpreted the correlation using an extended jet scenario for blazar emission.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.51.3-51.3
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• 2019

Its ability to measure the polarization of light at four frequencies makes the KVN a "plasma physics observatory" that can probe the internal physics (e.g., magnetic fields, outflow geometries) of AGN radio jets and cores. We initiated a Key Science Program, the Plasma-physics of Active Galactic Nuclei (PAGaN) project, dedicated to polarimetric monitoring of 14 radio-bright AGN. We have been able to measure the Faraday rotation measure of the cores of our targets as function of frequency; the observed scaling relation is in good agreement with conically expanding outflows to first order. We are further probing a polarized hotspot in the jet of 3C84 and possible systematic differences in the Faraday rotation in BL Lacertae objects and flat spectrum radio quasars.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.51.1-51.1
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• 2015

Over several decades, a historical review of receiver development for radio astronomy in Korea such TRAO, SRAO and KVN will be presented.

• The Bulletin of The Korean Astronomical Society
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• v.31 no.1
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• pp.50.2-50.2
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• 2006

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.52.1-52.1
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• 2004

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.55.1-55.1
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• 2004

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.56.1-56.1
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• 2004

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.56.2-56.2
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• 2004

• The Bulletin of The Korean Astronomical Society
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• v.29 no.2
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• pp.55.2-55.2
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• 2004