Gamma-ray Luminosity and Photon Index Evolution of FSRQ Blazars and Contribution to the Gamma-ray Background

We present the redshift evolutions and distributions of the gamma-ray luminosity and photon spectral index of flat spectrum radio quasar (FSRQ) type blazars, using non-parametric methods to obtain the evolutions and distributions directly from the data. The sample we use for analysis consists of almost all FSRQs observed with a greater than approximately 7 sigma detection threshold in the first year catalog of the Fermi Gamma-ray Space Telescope's Large Area Telescope, with redshfits as determined from optical spectroscopy by Shaw et al. We find that FSQRs undergo rapid gamma-ray luminosity evolution, but negligible photon index evolution, with redshift. With these evolutions accounted for we determine the density evolution and luminosity function of FSRQs, and calculate their total contribution to the extragalactic gamma-ray background radiation, resolved and unresolved, which is found to be 16(+10/-4)%, in agreement with previous studies.Comment: 9 pages, 10 figures, Accepted to Ap

Approximate solutions of radiative transfer in dusty nebulae. 2: Hydrogen and helium

The ionization structure of hydrogen and helium in dusty nebulae is discussed. The general equations for pure hydrogen nebulae are modified to include helium. An approximate analytic solution is presented for Stroemgren radii of hydrogen and helium in the absence of dust. It is shown that these results, with simple modifications, are also applicable to dusty nebulae where the effective absorption cross section of dust grains varies slowly with frequency in the 1000 to 200A range. No analytic solutions are possible if this cross section varies rapidly with frequency. In this case, however, simple coupled differential equations are derived. Approximate analytic expressions are presented for evaluation of the variation of the fraction of ionizing radiation absorbed by dust and the ratio of the volume emission measures of He II to H II regions with the spectrum of the ionizing source, helium abundance, and absorption properties of dust. The effects of dust on the He III zone are discussed. Results are restricted to spherically symmetric nebulae, but nonuniform gas and dust distributions and clumpiness can be taken into account

New data on the peculiar galaxy MRK 273

Colorimetric and spectral investigations of Markarian 273 and its three neighbors were performed on the basis of direct ultraviolet blue visual (UBV) and spectral observations with the 2-m Tautenburg telescope and the 6-m telescope of the Special Astrophysical Observatory of the USSR Academy of Sciences. The results obtained suggest that this galaxy is a close system of two objects with active nuclei. The observed straight tail with a thermal emission character is probably the result of the interaction of these galaxies

The interpretation of hard X-ray polarization measurements in solar flares

Observations of polarization of moderately hard X-rays in solar flares are reviewed and compared with the predictions of recent detailed modeling of hard X-ray bremsstrahlung production by non-thermal electrons. The recent advances in the complexity of the modeling lead to substantially lower predicted polarizations than in earlier models and more fully highlight how various parameters play a role in determining the polarization of the radiation field. The new predicted polarizations are comparable to those predicted by thermal modeling of solar flare hard X-ray production, and both are in agreement with the observations. In the light of these results, new polarization observations with current generation instruments are proposed which could be used to discriminate between non-thermal and thermal models of hard X-ray production in solar flares

On the Role of Minor Galaxy Mergers in the Formation of Active Galactic Nuclei

The large scale (~ 100 kpc) environments of Seyfert galaxies are not significantly different from those of non-Seyfert galaxies. In the context of the interaction model of the formation of active galactic nuclei (AGN), it has been proposed that AGN form via "minor mergers" of large disk galaxies with smaller companions. We test this hypothesis by comparing the nuclear spectra of 105 bright nearby galaxies with measurements of their R or r band morphological asymmetries at three successive radii. We find no significant differences in these asymmetries between the 13 Seyfert galaxies in the sample and galaxies having other nuclear spectral types (absorption, H II-region like, LINER), nor is there strong qualitative evidence that such mergers have occured among any of the Seyferts or LINERs. Thus either any minor mergers began > 1 Gyr ago and are essentially complete, or they did not occur at all, and AGN form independently of any type of interaction. Support for the latter interpretation is provided by the growing evidence that supermassive black holes exist in the cores of most elliptical and early-type spiral galaxies, which in turn suggests that nuclear activity represents a normal phase in the evolution of the bulges of massive galaxies. Galaxy mergers may increase the luminosity of Seyfert nuclei to the level of QSOs, which could explain why the latter objects appear to be found in rich environments and in interacting systems.Comment: 13 pages, 2 figures, to appear in Astrophysical Journal Letter

Controlling stress state of a hoisting shaft frame in the context of specific freezing process

Purpose is to obtain regularities of a stress state of such multilayer system as neighbourhood rock mass – frozen soil – hoisting shaft frame in the process of numerical analysis to control a frame state with the selection of efficient parameters; thickness depending upon a specific frozen process specifically. Methods. Numerical analysis on the basis of a finite-element method has been implemented relying upon Pro Complex Structure CAD for Windows (SCAD) which made it possible to obtain stress state of a hoisting shaft frame and its interaction with ice-soil blocking as well as with neighbourhood rock mass soil. Findings. Hoisting shaft model has been developed. The model is based upon actual geometry and results of laboratory studies. Three blocking types (i.e. reinforced-concrete blocks, gray cast-iron tubbings, and modified gray cast-iron tubbings) and two soil types (i.e. sand and clayish soil at +8°С temperature) in terms of different freezing temperatures (i.e. (–2, –6 and –10°С) were analyzed numerically with the use of the SCAD. Results of the research have helped identify dependences concerning formation of a stress state of the multilayer neighbourhood rock mass – frozen soil – hoisting shaft frame system while varying properties of the listed types of a frame, neighbourhood rock mass, and ice-soil blocking. Regularities of the stressed state components deepening upon the frozen soil elasticity modulus, corresponding to its certain temperature, and elasticity modulus of a hoisting shaft frame have been obtained. The regularities connect changes in the stress of a hoisting shaft blocking in the context of specific freezing process. Originality. The obtained dependences of the stressed state of a hoisting shaft frame on the soil elasticity modulus and the material are composite spatial surfaces reflecting representatively the stressed state of such multilayer systems as neighbourhood rock mass – frozen soil – hoisting shaft frame. Practical implications. The regularities of the stressed state, determined for such multilayer systems as neighbourhood rock mass – frozen soil – hoisting shaft frame, make it possible to control stress components selecting rational geometry of a frame and its material or temperature cycle to freeze soils while applying the specific method.Мета. Отримання в ході чисельного аналізу закономірностей зміни напруженого стану багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру” для управління напруженим станом оправи із підбором ефективних параметрів (наприклад, товщини) в залежності від параметрів спеціального способу заморожування. Методика. Застосовано чисельний аналіз на основі методу скінченних елементів, реалізований на базі професійного комплексу Structure CAD for Windows (SCAD), що дозволив отримати напружений стан оправи шахтного стовбуру із його взаємодією із льодоґрунтовим огородженням та ґрунтом оточуючого масиву. Результати. Створено модель шахтного стовбура, що побудована на основі реальних геометричних розмірів і результатів лабораторних досліджень. В ході чисельного аналізу із застосуванням SCAD досліджено три типи оправи (залізобетонні блоки, тюбінги з сірого чавуну та тюбінги з модифікованого сірого чавуну), два типи ґрунтів (пісок та суглинок при температурі +8°С) при різних температурах заморожування (–2, –6 і –10°С). Результати досліджень дозволили відшукати залежності формування напруженого стану багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру” при варіації властивостей вказаних типів оправи, ґрунту оточуючого масиву та льодоґрунтового огородження. Отримано закономірності компонент напруженого стану від модуля пружності замороженого ґрунту, що відповідає певній його температурі, та модуля пружності оправи шахтного стовбуру. Дані закономірності пов’язують зміну напружень оправи шахтного стовбуру при спеціальному способі заморожування. Наукова новизна. Отримані залежності компонент напруженого стану оправи шахтного стовбуру від модулю пружності ґрунту та матеріалу є складними просторовими поверхнями, що репрезентативно відображають напружений стан багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру”. Практична значимість. Закономірності напруженого стану, визначені для багатошарової системи “ґрунт оточуючого масиву – заморожений ґрунт – оправа шахтного стовбуру”, дозволяють управляти компонентами напружень, підбираючи раціональні геометричних параметри та матеріал оправи, або температуру циклу заморожування ґрунтів при застосуванні цього спеціального способу.Цель. Получение в ходе численного анализа закономерностей изменения напряженного состояния многослойной системы “ґрунт окружающего массива – замороженный грунт – оправа шахтного ствола” для управления напряженным состоянием оправы с подбором эффективных параметров (например, толщины) в зависимости от параметров специального способа замораживания. Методика. Применен численный анализ на основе метода конечных элементов, реализованный на базе про-профессионального комплекса Structure CAD for Windows (SCAD), позволивший получить напряженное состояние оправы шахтного ствола с его взаимодействием с льодоґрунтовым ограждением и грунтом окружающего массива. Результаты. Создана модель шахтного ствола, построенная на основе реальных геометрических размеров и результатов лабораторных исследований. В ходе численного анализа с применением SCAD исследованы три типа оправы (железобетонные блоки, тюбинги из серого чугуна и тюбинги из модифицированного серого чугуна), два типа грунтов (песок и суглинок при температуре +8°С) при различных температурах замораживания (–2, –6 и –10°С). Результаты исследований позволили отыскать зависимости формирования напряженного состояния многослойной системы “грунт окружающего массива – замороженный грунт – оправа шахтного ствола” при вариации свойств указанных типов оправы, грунта окружающей массива и льодоґрунтового ограждения. Получены закономерности компонент напряженного состояния от модуля упругости замороженного грунта, что соответствует определенной его температуре, и модуля упругости оправы шахтного ствола. Данные закономерности связывают изменение напряжений оправы шахтного ствола при специальном способе замораживания. Научная новизна. Полученные зависимости компонент напряженного состояния оправы шахтного ствола от модуля упругости грунта и материала являются сложными пространственными поверхностями, репрезентативно отражающие напряженное состояние многослойной системы “грунт окружающей массива – замороженный грунт – оправа шахтного ствола”. Практическая значимость. Закономерности напряженного состояния, определенные для многослойной системы “грунт окружающей массива – замороженный грунт – оправа шахтного ствола”, позволяют управлять компонентами напряжений, подбирая рациональные геометрические параметры и материал оправы, или температуру цикла замораживания грунтов при применении этого специального способа.The results of the study were obtained in the process of implementing the state-financed research Analytical regularities of a stress-strain state of frame of hoisting shafts while specific operation performing (official registration No. 0117U006810). The authors express thanks to S.M. Likhman, Chief Engineer of Kyivmetrobud PJSC, and M.V. Bilous, Candidate of Science and Director of a Ukrheodezmark being a subsidiary company of Kyivmetrobud PJSC for their counseling as for the specific method of soil freezing and selection of rational designs of a hoisting shaft

Optical radiation from the Crab pulsar

Possible mechanisms for producing the optical radiation from the Crab pulsar are proposed and discussed. There are severe difficulties in interpreting the radiation as being produced by an incoherent process, whether it be synchrotron radiation, inverse-Compton radiation or curvature radiation. It is proposed therefore that radiation in the optical part of the spectrum is coherent. In the polar cap model, a small bunch of electrons and positrons forms near each primary electron as a result of the pair-production cascade process. Ambient electric fields give rise to energy separation, as a result of which either the electrons or positrons will dominate the radiation from each bunch. The roll-off in the infrared is ascribed to synchrotron absorption by electrons and positrons located between the surface of the star and the force-balance radius. Various consequences of this model, which may be subjected to observational test, are discussed

Close pairs of galaxies with different activity levels

We selected and studied 180 pairs with dV < 800 km/s and Dp < 60 kpc containing Markarian (MRK) galaxies to investigate the dependence of galaxies' integral parameters, star-formation (SF) and active galactic nuclei (AGN) properties on kinematics of pairs, their structure and large-scale environments. Projected radial separation Dp and perturbation level P are better measures of interaction strength than dV. The latter correlates with the density of large-scale environment and with the morphologies of galaxies. Both galaxies in a pair are of the same nature, the only difference is that MRK galaxies are usually righter than their neighbors. Specific star formation rates (SSFR) of galaxies in pairs with smaller Dp or dV is in average 0.5 dex higher than that of galaxies in pairs with larger Dp or dV. Closeness of a neighbor with the same and later morphological type increases the SSFR, while earlier-type neighbors do not increase SSFR. Major interactions/mergers trigger SF and AGN more effectively than minor ones. The fraction of AGNs is higher in more perturbed pairs and pairs with smaller Dp. AGNs typically are in stronger interacting systems than star-forming and passive galaxies. There are correlations of both SSFRs and spectral properties of nuclei between pair members.Comment: 4 pages, 3 figures. arXiv admin note: substantial text overlap with arXiv:1310.024