Multi-wavelength observations of the gamma-ray flaring quasar S4 1030+61 in 2009-2014

We present a study of the parsec-scale multi-frequency properties of the quasar S4 1030+61 during a prolonged radio and gamma-ray activity. Observations were performed within Fermi gamma-ray telescope, OVRO 40-m telescope and MOJAVE VLBA monitoring programs, covering five years from 2009. The data are supplemented by four-epoch VLBA observations at 5, 8, 15, 24, and 43 GHz, which were triggered by the bright gamma-ray flare, registered in the quasar in 2010. The S4 1030+61 jet exhibits an apparent superluminal velocity of (6.4+-0.4)c and does not show ejections of new components in the observed period, while decomposition of the radio light curve reveals nine prominent flares. The measured variability parameters of the source show values typical for Fermi-detected quasars. Combined analysis of radio and gamma-ray emission implies a spatial separation between emitting regions at these bands of about 12 pc and locates the gamma-ray emission within a parsec from the central engine. We detected changes in the value and direction of the linear polarization and the Faraday rotation measure. The value of the intrinsic brightness temperature of the core is above the equipartition state, while its value as a function of distance from the core is well approximated by the power-law. Altogether these results show that the radio flaring activity of the quasar is accompanied by injection of relativistic particles and energy losses at the jet base, while S4 1030+61 has a stable, straight jet well described by standard conical jet theories.Comment: accepted by MNRAS, 16 pages, 14 figures, 8 tables, 5 pages of supplementary materia

Causal connection in parsec-scale relativistic jets: results from the MOJAVE VLBI survey

We report that active galactic nucleus (AGN) jets are causally connected on parsec scales, based on 15 GHz Very Long Baseline Array (VLBA) data from a sample of 133 AGN jets. This result is achieved through a new method for measuring the product of the jet Lorentz factor and the intrinsic opening angle Gamma*theta_j from measured apparent opening angles in flux density limited samples of AGN jets. The Gamma*theta_j parameter is important for jet physics because it is related to the jet-frame sidewise expansion speed and causal connection between the jet edges and its symmetry axis. Most importantly, the standard model of jet production requires that the jet be causally connected with its symmetry axis, implying that Gamma*theta_j < 1. When we apply our method to the MOJAVE flux density limited sample of radio loud objects, we find Gamma*theta_j = 0.2, implying that AGN jets are causally connected. We also find evidence that AGN jets viewed very close to the line of sight effectively have smaller intrinsic opening angles compared with jets viewed more off-axis, which is consistent with Doppler beaming and a fast inner spine/slow outer sheath velocity field. Notably, gamma-ray burst (GRB) jets have a typical Gamma*theta_j that is two orders of magnitude higher, suggesting that different physical mechanisms are at work in GRB jets compared to AGN jets. A useful application of our result is that a jet's beaming parameters can be derived. Assuming Gamma*theta_j is approximately constant in the AGN jet population, an individual jet's Doppler factor and Lorentz factor (and therefore also its viewing angle) can be determined using two observable quantities: apparent jet opening angle and the apparent speed of jet components.Comment: 9 pages, 4 figure

Kubo formula for Floquet states and photoconductivity oscillations in a 2D electron gas

The recent discovery of the microwave induced vanishing resistance states in a two dimensional electron system (2DES) is an unexpected and surprising phenomena. In these experiments the magnetoresistance of a high mobility 2DES under the influence of microwave radiation of frequency $\omega$ at moderate values of the magnetic field, exhibits strong oscillations with zero-resistance states (ZRS) governed by the ratio $\omega /\omega_c$, where $\omega_c$ is the cyclotron frequency. In this work we present a model for the photoconductivity of a two dimensional electron system (2DES) subjected to a magnetic field. The model includes the microwave and Landau contributions in a non-perturbative exact way, impurity scattering effects are treated perturbatively. In our model, the Landau-Floquet states act coherently with respect to the oscillating field of the impurities, that in turn induces transitions between these levels. Based on this formalism, we provide a Kubo-like formula that takes into account the oscillatory Floquet structure of the problem. We study the effects of both short-range and long-range disorder on the photoconductivity. Our calculation yields a magnetoresistance oscillatory behavior with the correct period and phase. It is found that, in agreement with experiment, negative dissipation can only be induced in very high mobility samples. We analyze the dependence of the results on the microwave power and polarization. For high-intensity radiation multi-photon processes take place predicting new negative-resistance states centered at $\omega / \omega_c=1/2$, and $\omega / \omega_c= 3/2$.Comment: Final version, accepted for publication in Phys. Rev.

MOJAVE: Monitoring of Jets in AGN with VLBA Experiments. VII. Blazar Jet Acceleration

We discuss acceleration measurements for a large sample of extragalactic radio jets from the MOJAVE program which studies the parsec-scale jet structure and kinematics of a complete, flux-density-limited sample of Active Galactic Nuclei (AGN). Accelerations are measured from the apparent motion of individual jet features or "components" which may represent patterns in the jet flow. We find that significant accelerations are common both parallel and perpendicular to the observed component velocities. Parallel accelerations, representing changes in apparent speed, are generally larger than perpendicular acceleration that represent changes in apparent direction. The trend for larger parallel accelerations indicates that a significant fraction of these changes in apparent speed are due to changes in intrinsic speed of the component rather than changes in direction to the line of sight. We find an overall tendency for components with increasing apparent speed to be closer to the base of their jets than components with decreasing apparent speed. This suggests a link between the observed pattern motions and the underlying flow which, in some cases, may increase in speed close to the base and decrease in speed further out; however, common hydro-dynamical processes for propagating shocks may also play a role. About half of the components show "non-radial" motion, or a misalignment between the component's structural position angle and its velocity direction, and these misalignments generally better align the component motion with the downstream emission. Perpendicular accelerations are closely linked with non-radial motion. When observed together, perpendicular accelerations are usually in the correct direction to have caused the observed misalignment.Comment: 17 pages, 11 figures, 1 table, accepted by the Astrophysical Journa

Magnetovibrational coupling in small cantilevers

A nano-magnetomechanical system consisting of a cantilever and a thin magnetic film is predicted to display magnetovibrational modes, which should enable applications for sensors and actuators. The {}``polaritonic{}'' modes can be detected by line splittings in ferromagnetic resonance spectra.Comment: 8 pages, 3 figure

РОЛЬ ОСНОВНИХ ЗАСОБІВ У ФОРМУВАННІ КАПІТАЛУ ПІДПРИЄМСТВА, ЇХНЯ ОЦІНКА ТА КОНТРОЛЬ

The article deals with the problem of valuation and control of non-current assets, in particular of fixed assets, determination of their role in the formation of the enterprise’s own capital, their correct and reliable evaluation at the enterprise. The need to study the effectiveness of using non-current assets at the enterprise to make sound management decisions, in particular regarding the composition of fixed assets, their updating and use is defined. The necessity of studying the influence of fixed assets on the amount of gross product is substantiated. It should be noted that non-current assets, in particular fixed assets, have a significant place in the capital formation. Therefore, in the process of managing non-current assets at the enterprise such managerial tasks are decided as substantiation of renewal fixed assets possible forms, determination of possible ways and the need for their growth, formation of necessary financial resources for acquisition of fixed assets and increase the are efficiency. Correct and substantiated non-current assets accounting system at the enterprise has a significant influence on the quality of accounting and control in general. Professionals know that without the ability to proper and quick assess business value it is impossible to get a wide middle class of owners, sustainable and dynamic market development, prevention of financial pyramids, economic lawlessness, investor mistrust and, as a result, creation of a legal and proper micro- and macroeconomic environment. The economies of Germany, France, the United States, Japan and other developed countries are based on this ability. Multi-factor economic and mathematical modeling taking into account microeconomic factors is carried out. It is proved that certain rates of development and increase of production efficiency at Ukrainian enterprises are possible provided the intensification of reproduction and better use of existing fixed assets of the enterprise, finding internal reserves for the growth of production efficiency, such as optimization of the structure of assets and the number of employees.Рассмотрена проблема оценки и контроля необоротных активов, в частности основных средств, определение их роли в формировании собственного капитала предприятия, проведение их правильной и достоверной оценки на предприятии. Определена необходимость исследования эффективности использования необоротных активов на предприятии для принятия правильных управленских решений, в частности по поводу формирования состава основных средств, их обновления и использования. Необоротные активы, в частности основные средства, играют важную роль в формировании капитала предприятия. А поэтому в процессе управления необоротными активами на предприятии решаются такие комплексы управленческих задач, как обоснование возможных форм обновления основных средств, определение их наращивания та возможных способов расширения их использования, формирование необходимых финансовых ресурсов для приобретения, повышения эффективности использования введенных в действие основных средств. Верное и обоснованное построение учета необоротных активов на предприятии имеет значительное влияние на качество учета и контроля в целом. Высококвалифицированному специалисту известно, что без умения правильно и быстро оценивать стоимость любого бизнеса невозможно создание среднего класса собственников, стойкого и динамического развития рыночных условий, упреждений финансовых пирамид, экономического беззакония, недоверия партнеров инвесторов, а в конечном результате создание законного и честного экономического микро- и макроклимата. На таком умении основано функционирование экономики Германии, Франции, США, Японии и других развитых стран. Обоснована необходимость исследования влияния основных средств на объём валового продукта. Проведено многофакторное математическое моделирование с учётом микроэкономических факторов. Доказано, что обеспечение конкретных темпов роста и повышения эффективности производства на украинских предприятиях возможно при условии интенсификации воспроизводства и лучшего использования действующих основных средств предприятия, нахождение внутренних резервов для роста эффективности производства, таких как оптимизация структуры активов и численности работников.Розглянуто проблему оцінки і контролю необоротних активів, зокрема основних засобів, визначення їхньої ролі у формуванні власного капіталу підприємства, здійснення їхньої правильної та достовірної оцінки на підприємстві. Визначено необхідність дослідження ефективності використання необоротних активів на підприємстві для ухвалення правильних управлінських рішень, зокрема щодо формування складу основних засобів, їх оновлення та використання. Необоротні активи, зокрема основні засоби, відіграють важливу роль у формуванні капіталу підприємства. А тому у процесі управління необоротними активами на підприємстві вирішуються такі комплекси управлінських завдань, як обґрунтування можливих форм оновлення основних засобів, визначення потреби в їхньому нарощенні та можливих способів розширення, формування необхідних фінансових ресурсів для придбання, підвищення ефективності використання введених у дію основних засобів. Правильна та обґрунтована побудова обліку необоротних активів на підприємстві має значний вплив на якість обліку та контролю в цілому. Кваліфікованому спеціалістові одразу видно, що без уміння правильно і швидко оцінювати вартість будь-якого бізнесу неможливо створення середнього класу власників, стійкого і динамічного розвитку ринкових умов, запобігання фінансовим пірамідам, економічного беззаконня, недовіри партнерів інвесторів, а в кінцевому підсумку створення законного і чесного економічного мікро- і макроклімату. На такому вмінні засновано функціонування економіки Німеччини, Франції, США, Японії та інших розвинутих країн. Обґрунтовано необхідність дослідження впливу основних засобів на обсяг валового продукту. Проведено багатофакторне економіко-математичне моделювання з урахуванням мікроекономічних факторів. Доведено, що забезпечення певних темпів розвитку і підвищення ефективності виробництва на українських підприємствах можливе за умови інтенсифікації відтворення та ліпшого використання наявних основних засобів підприємства, знаходження внутрішніх резервів для зростання ефективності виробництва, таких як оптимізація структури активів і чисельності працівників

MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. VI. Kinematics Analysis of a Complete Sample of Blazar Jets

We discuss the jet kinematics of a complete flux-density-limited sample of 135 radio-loud active galactic nuclei (AGN) resulting from a 13 year program to investigate the structure and evolution of parsec-scale jet phenomena. Our analysis is based on new 2 cm Very Long Baseline Array (VLBA) images obtained between 2002 and 2007, but includes our previously published observations made at the same wavelength, and is supplemented by VLBA archive data. In all, we have used 2424 images spanning the years 1994-2007 to study and determine the motions of 526 separate jet features in 127 jets. The data quality and temporal coverage (a median of 15 epochs per source) of this complete AGN jet sample represents a significant advance over previous kinematics surveys. In all but five AGNs, the jets appear one-sided, most likely the result of differential Doppler boosting. In general the observed motions are directed along the jet ridge line, outward from the optically thick core feature. We directly observe changes in speed and/or direction in one third of the well-sampled jet components in our survey. While there is some spread in the apparent speeds of separate features within an individual jet, the dispersion is about three times smaller than the overall dispersion of speeds among all jets. This supports the idea that there is a characteristic flow that describes each jet, which we have characterized by the fastest observed component speed. The observed maximum speed distribution is peaked at ~10c, with a tail that extends out to ~50c. This requires a distribution of intrinsic Lorentz factors in the parent population that range up to ~50. We also note the presence of some rare low-pattern speeds or even stationary features in otherwise rapidly flowing jets... (abridged)Comment: 19 pages, 10 figures, 2 tables, accepted by the Astronomical Journal; online only material is available from http://www.cv.nrao.edu/2cmVLBA/pub/MOJAVE_VI_suppl.zi

Catching the Radio Flare in CTA 102 III. Core-Shift and Spectral Analysis

The temporal and spatial spectral evolution of the jets of AGN can be studied with multi-frequency, multi-epoch VLBI observations. The combination of both, morphological and spectral parameters can be used to derive source intrinsic physical properties such as the magnetic field and the non-thermal particle density. In the first two papers of this series, we analyzed the single-dish light curves and the VLBI kinematics of the blazar CTA 102 and suggested a shock-shock interaction between a traveling and a standing shock wave as a possible scenario to explain the observed evolution of the component associated to the 2006 flare. In this paper we investigate the core-shift and spectral evolution to test our hypothesis of a shock-shock interaction. We used 8 multi-frequency VLBA observations to analyze the temporal and spatial evolution of the spectral parameters during the flare. We observed CTA 102 between May 2005 and April 2007 using the VLBA at six different frequencies spanning from 2 - 86 GHz. After the calibrated VLBA images were corrected for opacity, we performed a detailed spectral analysis. From the derived values we estimated the magnetic field and the density of the relativistic particles. The detailed analysis of the opacity shift reveals that the position of the jet core is proportional to nu^-1 with some temporal variations. The value suggests possible equipartition between magnetic field energy and particle kinetic energy densities at the most compact regions. From the variation of the physical parameters we deduced that the 2006 flare in CTA 102 is connected to the ejection of a new traveling feature (t=2005.9) and the interaction between this shock wave and a stationary structure around 0.1 mas from the core. The source kinematics together with the spectral and structural variations can be described by helical motions in an over-pressured jet.Comment: 35 pages, 46 figure

The Relation between Radio Polarization and Gamma-ray Emission in AGN Jets

We have compared the parsec-scale jet linear polarization properties of the Fermi LAT-detected and non-detected sources in the complete flux-density-limited (MOJAVE-1) sample of highly beamed AGN. Of the 123 MOJAVE sources, 30 were detected by the LAT during its first three months of operation. We find that during the era since the launch of Fermi, the unresolved core components of the LAT-detected jets have significantly higher median fractional polarization at 15 GHz. This complements our previous findings that these LAT sources have higher apparent jet speeds, brightness temperatures and Doppler factors, and are preferentially found in higher activity states.Comment: 6 pages, 3 figures, to appear in the proceedings of "High Energy Phenomena In Relativistic Outflows II" (Buenos Aires, Argentina, October 26-30, 2009) International Journal of Modern Physics