We present a study of the inexplicit connection between radio jet activity and γ-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two γ-ray outbursts (in November 2013 and March 2015) can be seen in γ-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of 41185 days, 352±79 days, 310±57 days, and 283±55 days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths B ∼ 2 μT and electron Lorentz factors γ ∼ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we nd that the decay timescale  scales with frequency τ ν - 0.2. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the γ-ray outbursts. The spectral evolution is consistent with the `generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second -ray event indicate that this γ-ray outburst might be an `orphan' are powered by the `ring of fire' mechanism.

Active galactic nuclei (AGN) are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. On such short timescales, unexplored territory, such as the possible existence of a shortest characteristic time scale of activity and the shape of the high frequency end of AGN power spectra, still exists. We present the results of AGN single-dish fast photometry performed with the Korean VLBI Network (KVN). Observations were done in a “anti-correlated” mode using two antennas, with always at least one antenna pointing at the target. This results in an effective time resolution of less than three minutes. We used all four KVN frequencies, 22, 43, 86, and 129 GHz, in order to trace spectral variability, if any. We were able to derive high-quality light curves for 3C 111, 3C 454.3, and BL Lacertae at 22 and 43 GHz, and for 3C 279 at 86 GHz, between May 2012 and April 2013. We performed a detailed statistical analysis in order to assess the levels of variability and the corresponding upper limits. We found upper limits on flux variability ranging from ∼1.6% to ∼7.6%. The upper limits on the derived brightness temperatures exceed the inverse Compton limit by three to six orders of magnitude. From our results, plus comparison with data obtained by the University of Michigan Radio Astronomy Observatory, we conclude that we have not detected source-intrinsic variability which would have to occur at sub-per cent levels.

We report first results from KVN and VERA Array (KaVA) VLBI observations obtained in the frame of our Plasma-physics of Active Galactic Nuclei (PAGaN) project. We observed eight selected AGN at 22 and 43 GHz in single polarization (LCP) between March 2014 and April 2015. Each source was observed for 6 to 8 hours per observing run to maximize the uv coverage. We obtained a total of 15 deep high-resolution images permitting the identification of individual circular Gaussian jet components and three spectral index maps of BL Lac, 3C 111 and 3C 345 from simultaneous dual-frequency observations. The spectral index maps show trends in agreement with general expectations – flat core and steep jets – while the actual value of the spectral index for jets shows indications for a dependence on AGN type. We analyzed the kinematics of jet components of BL Lac and 3C 111, detecting superluminal proper motions with maximum apparent speeds of about 5c. This constrains the lower limits of the intrinsic component velocities to  0.98c and the upper limits of the angle between jet and line of sight to 20◦. In agreement with global jet expansion, jet components show systematically larger diameters d at larger core distances r, following the global relation d  0.2r, albeit within substantial scatter.

Active Galactic Nuclei (AGN) with bright radio jets oer the opportunity to study the structure of and physical conditions in relativistic out ows. For such studies, multi-frequency polarimetric very long baseline interferometric (VLBI) observations are important as they directly probe particle densities, magnetic eld geometries, and several other parameters. We present results from rst-epoch data obtained by the Korean VLBI Network (KVN) within the frame of the Plasma Physics of Active Galactic Nuclei (PAGaN) project. We observed seven radio-bright nearby AGN at frequencies of 22, 43, 86, and 129 GHz in dual polarization mode. Our observations constrain apparent brightness temperatures of jet components and radio cores in our sample to > 108:01 K and > 109:86 K, respectively. Degrees of linear polarization mL are relatively low overall: less than 10%. This indicates suppression of polarization by strong turbulence in the jets. We found an exceptionally high degree of polarization in a jet component of BL Lac at 43 GHz, with mL  40%. Assuming a transverse shock front propagating downstream along the jet, the shock front being almost parallel to the line of sight can explain the high degree of polarization.

In this paper we introduce the Plasma Physics of Active Galactic Nuclei project, which is an ongoing experiment with Korean VLBI Network (KVN) and KVN and VERA Array (KaVA) to study multi- frequency polarimetric properties on parsec scales of active galaxies. The goal of the project is to improve our understanding of fundamental jet physics, especially evolution of the relativistic out ow coupled with the large-scale magnetic field. We selected six radio-loud AGN as our targets. So far we (i) detected resolved emissions regions at 86 and 129 GHz on VLBI scales, (ii) constructed 2D spectral index maps of the out ows, and (iii) found polarizations at 22 and 43 GHz for a few targets. Here we present spectral index distributions of 3C 120 between 22 and 43 GHz and a linear polarization map of BL Lac at 43 GHz obtained with KVN.

목적: 본 연구의 목적은 사격 소총 선수 1명을 대상으로 긍정심리기법을 활용한 심리기술훈련이 심리변화와 경기력에 미치는 효과를 분석하는 것이다. 방법: 연구목적을 달성하기 위해 단일피험자 사례설계를 활용하였으며, 긍정심리자본, 스포츠수행전략, 심박변이도, 경기결과 분석, 심층면담을 통해 심리기술훈련의 효과를 확인하였다. 심리기술훈련 프로그램은 긍정심리기법, 목표설정, 루틴개발, 심상훈련, 이완훈련, 주의집중을 주제로 총 40주간 사전단계, 훈련단계, 사후단계로 구분하여 적용하였다. 결과: 긍정심리기법을 활용한 심리기술훈련 적용 결과 긍정 심리자본, 스포츠수행전략, 심박변이도는 물론 경기력이 긍정적으로 변화되었다. 결론: 연구대상자에게 적용된 긍정심리기법은 긍정적인 정서유발을 통해 부정적 정서와 사고를 효과적으로 대처하여 주 호소문제가 해결되었다고 사료된다. 현재 국내 선수경기력 향상을 위한 심리기술훈련 기법은 비교적 한정적인 관계로 다수의 종목 및 포지션에 따른 세심한 심리기술 적용이 제한되어 있다. 이에 후속연구에서는 긍정심리기법을 적용한 다양한 연구들이 시도되어야 한다.