Multiwavelength observations of the blazar BL Lacertae: a new fast TeV γ-ray flare

Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan (South Korea). Published in Proceeding of Science.Observations of fast TeV γ-ray flares from blazars reveal the extreme compactness of emitting regions in blazar jets. Combined with very-long-baseline radio interferometry measurements, they probe the structure and emission mechanism of the jet. We report on a fast TeV γ-ray flare from BL Lacertae observed by VERITAS, with a rise time of about 2.3 hours and a decay time of about 36 minutes. The peak flux at >200 GeV measured with the 4-minute binned light curve is (4.2±0.6)×10−6photonsm−2s−1, or ∼180% the Crab Nebula flux. Variability in GeV γ-ray, X-ray, and optical flux, as well as in optical and radio polarization was observed around the time of the TeV γ-ray flare. A possible superluminal knot was identified in the VLBA observations at 43 GHz. The flare constrains the size of the emitting region, and is consistent with several theoretical models with stationary shocks

Behaviour of the Blazar CTA 102 during two giant outbursts

Blazar CTA 102 underwent exceptional optical and high-energy outbursts in 2012 and 2016-2017. We analyze its behaviour during these events, focusing on polarimetry as a tool that allows us to trace changes in the physical conditions and geometric configuration of the emission source close to the central black hole. We also use Fermi gamma-ray data in conjunction with optical photometry in an effort to localize the origin of the outbursts.AST-1615796 - Boston Universit

The Sustainable Development Goals for Eastern Partnership Countries: Impact of Institutions

In 2015 UN established 17 Sustainable Development Goals (SDGs) as priorities for further development for 193 member countries. SDGs include 169 targets, which cover all issues of sustainability. Governments require specific researches to elaborate adequate strategies considering current parameters of social and economic development of countries. Eastern Partnership countries and the Russian Federation are classified as countries in transition with not really powerful economies. Therefore it’s very important to increase the efficiency of expenditures through enhancing institutions. This study attempts to research dependencies between changes in quality of institutions and SDGs performance for countries in transition. Panel data regression with offered Composite Index of Sustainable development Goals as dependent variable defines significance of links and can be used to define priorities in national policies

Сравнение отклика МОП-транзистора на воздействие рентгеновского и гамма-облучения

Introduction. Electromagnetic or ionizing radiation (IO) has great influence for radiation resistance of MOSFETs (metal–oxide–semiconductor field-effect transistors) and integrated circuits. Oxide, for the studied samples, is silicon dioxide, which acts as a dielectric in MOS structure. Currently, in literature there is no unambiguous idea of complete radiation response of MOSFETs to various types of ionizing radiation.Aim. To study radiation response of MOSFETs under influence of gamma and X-ray irradiation; to study effect of applied external potential of a gate substrate.Materials and methods. A total dose effect of gamma and X-ray radiation on the threshold voltage of MOSFET with a polysilicon gate and a gate oxide thickness of 120 nm with an applied external potential (-3, -2, 0, 3, 5, 10) V was studied. For gamma irradiation radionuclides cesium-137 with an energy of gamma quanta of 662 keV were used. X-ray tube with tungsten-rhenium cathode operated in modes 40 keV and 90 mkA was used as a source of X-ray radiation. Dose and time dependences of the change in the threshold voltage of n- and pchannel MOSFET were analyzed. It was performed that the influence of gamma and X-ray radiation led to the same effects in the studied structures. The maximum radiation response of MOSFETs was observed at high positive gate-substrate potentials. The approximation parameters associated with the concentration and capture cross sections of traps responsible for the formation of charges in the dielectric gate through irradiation were determined.Results. Strong influence of gamma and X-ray radiation led to the same effects in the studied structures. The applied voltage to the MOS structure during X-ray irradiation had a strong effect on their radiation response. The maximum radiation response of MOSFET at high positive gate-substrate potentials was observed. Proportionality coefficients to ensure the coincidence of the initial sections of the dose dependences for various applied gate-substrate potentials during irradiation were introduced. The coefficients allowed one to compare active and passive modes of operation of the X-ray emitter. Correction factors depended on the polarity of the applied gate-substrate potential. For negative potential, the proportionality coefficient value was 38.5. For the case of positive polarity the coefficient did not depend on the applied potential and the value was 120.Conclusion. The study allows one to determine the coefficients for dose dependences of threshold voltage changes. For the first time, to establish a numerical relations between the effects of various types of radiation sources at irradiation doses up to 1.9 · 104 Rad and proportionality coefficients becomes possible. It allows one to take into account the influence of applied potentials during irradiation on the radiation response of MOS structures.Введение. Ионизирующие излучения (ИИ) обладают большой проникающей способностью. В настоящее время в литературе нет однозначного представления о полном радиационном отклике МОПтранзисторов на различные виды ИИ (гамма- и рентгеновское). Поэтому наибольший интерес представляет радиационная стойкость МОП интегральных микросхем к воздействию этих излучений.Цель работы. Изучение отклика МОП-транзисторов на воздействие гамма- и рентгеновского облучения, а также изучение влияния на этот отклик приложенного во время рентгеновского облучения внешнего потенциала затвор‒подложка.Материалы и методы. Исследуемыми структурами являлись МОП-транзисторы с поликремниевым затвором при толщине оксида (диоксида кремния) 120 нм. Источником гамма-излучения выступали радионуклиды цезий-137, рентгеновского излучения – рентгеновская трубка с вольфрам-рениевым катодом. Анализировалось изменение порогового напряжения n- и p-канальных транзисторов методом транзисторной пары.Результаты. Гамма- и рентгеновское излучения приводят к одинаковым эффектам в исследуемых структурах. Приложение напряжения к МОП-структуре в процессе рентгеновского облучения оказывает сильное влияние на ее радиационный отклик. Максимальный радиационный отклик МОП-транзисторов наблюдался при больших положительных потенциалах затвор‒подложка. Были введены коэффициенты пропорциональности, обеспечивающие совпадение начальных участков дозовых зависимостей для различных приложенных потенциалов затвор‒подложка.Заключение. Определены значения коэффициентов пропорциональности зависимостей изменения порогового напряжения МОП-транзистора от дозы ИИ. Установлено численное соответствие между влиянием гамма- и рентгеновского изучений при дозах до 1.9 ·104 рад (коэффициент пропорциональности составил 38.5). Определены коэффициенты пропорциональности, позволяющие сопоставлять пассивный (без приложения потенциала) режим облучения гамма-квантами и активный (с приложением потенциала затвор‒подложка) режим облучения рентгеновскими квантами. Полученные поправочные коэффициенты зависят от полярности приложенного потенциала затвор‒подложка. Для отрицательного потенциала коэффициент пропорциональности составил 38.5. При приложении положительной полярности коэффициент не зависит от приложенного потенциала и составляет 120