Identification of extragalactic star forming complexes

Нами разработана методика выделения комплексов звездообразования в других галактиках на основании анализа карт излучения в различных спектральных диапазонах. В 17 близких галактиках нами были отобраны кандидаты в комплексы звездообразования на основании трех критериев, а именно исходя из наличия излучения полициклических ароматических углеводородов, излучения холодной пыли и ультрафиолетового излучения молодых звезд. Сопоставив информацию, полученную с помощью этих критериев, мы составили выборку комплексов звездообразования для выявления корреляций между различными индикаторами звездообразования.We developed a technique for selecting star forming complexes in external galaxies based on an analysis of radiation maps in various spectral bands. Using this method, we identified star formation complex candidates in 17 nearby galaxies applying three criteria. These criteria are polycyclic aromatic hydrocarbon emission, dust emission, and ultraviolet young star emission. Relating the information derived from these criteria, we made a sample of star forming regions suitable for revealing correlations between various star formation tracers

Modeling X-Ray Outbursts During Accretion onto Neutron Stars with Oblique Magnetic Axes

На основании модели частично проникающего магнитного поля в геометрически тонкий аккреционный диск была разработана аналитическая модель магнитных моментов сил, действующих на аккреционный диск помимо вязких моментов сил. С помощью полученной информации о магнитных моментах сил было модернизировано уравнение вязкой эволюции аккреционного диска. Измененные уравнения были реализованы внутри кода freddi, который численно решает уравнение вязкой эволюции. Также была исследована эволюция частоты вращения нейтронной звезды, на которую происходит аккреция. Произведено сравнение смоделированных зависимостей и экспериментальных данных: потоков в рентгеновском диапазоне для миллисекундного аккрецирующего рентгеновского пульсара Aql X-1 и эволюции частоты рентгеновского пульсара A0535+262.For the geometrically thin accretion disc partially permeated by the magnetic field of the central star, an analytic model of the magnetic torques, acting on the accretion disc alongside the viscous torques, has been developed. Accordingly, the equation of the viscous evolution of an accretion disc has been modified. The resulting model has been implemented within the program code ”freddi”, which numerically integrates the equations and calculates the evolution of disc parameters and light curves. Also, we have examined the change of rotation frequency of a neutron star, onto which the accretion proceeds. We compare our model with observational data, for example, fluxes in the X-ray band for the accreting millisecond X-ray pulsar Aql X-1 during an outburst and the rotation frequency evolution of the accreting X-ray pulsar A0535+262.Автор выражает благодарность Фонду развития теоретической физики и математики «БАЗИС» (номер гранта 21-2-1-31-1) и Российскому научному фонду (номер гранта 21-12-00141) за поддержку

Radial and Vertical Structure of Accretion Disk Penetrated by Magnetic Field of Neutron Star

В работе рассматривается влияние магнитного поля центральной звезды на стационарный аккреционный диск в предположении, что магнитное поле проникает в диск. Мы строим аналитическую модель взаимодействия магнитного поля с веществом в диске и исследуем, как вертикальная и радиальная структура диска зависит от магнитного поля. Для этого мы решаем модифицированную систему уравнений вертикальной структуры совместно с уравнением индукции магнитного поля. Обнаружено, что при наличии такого магнитного поля существенно меняется вид тензора вязких напряжений и, как следствие, радиальная структура диска и его спектр. Также мы исследуем зависимость полученных результатов от наклона магнитной оси.We consider effects of the magnetic field of a central star on a steady accretion disk assuming that magnetic field of a central star can penetrate the disk. We construct an analytical model of disk—magnetic field interaction and examine how the structure of the accretion disk depends on the magnetic field. We do this by solving the modified system of equations for the vertical structure self-consistently with the induction equation. It is shown the magnetic field can sufficiently modify the viscous tensor and, consequently, radial structure of the disk. We also examine the dependence of the results on the inclination of the magnetic axis of the neutron star.Авторы выражают благодарность гранту Российского научного фонда (номер гранта 21-12-00141)

Spatial variations in lead isotopes, Tasman Element, eastern Australia

Lead isotope data from ore deposits and mineral occurrences in the Tasman Element of eastern Australia have been used to construct isotopic maps of this region. These maps exhibit systematic patterns in parameters derived from isotope ratios. The parameters include μ (238U/204Pb), as calculated using the Cumming and Richards (1975) lead evolution model, and the difference between true age of mineralisation and the Cumming and Richards lead isotope model age of mineralisation (Δt). Variations in μ coincide with boundaries at the orogen, subprovince and zone scales. The boundary between the Lachlan and New England orogens is accompanied by a decrease in μ, and within the Lachlan Orogen, the Central Subprovince is characterised by μ that is significantly higher than in the adjacent Eastern and Western subprovinces. Within the Eastern Subprovince, the Cu-Au-rich Macquarie Arc is characterised by significantly lower μ relative to adjacent rocks. The Macquarie Arc is also characterised by very high Δt (generally above 200 Myr). Other regions characterised by very high Δt include western Tasmania, the southeastern New England Orogen, and the Hodgkinson Province in northern Queensland. These anomalies are within a broad pattern of decreasing Δt from east to west, with Paleozoic deposits within or adjacent to Proterozoic crust characterised by Δt values of 50 Myr or below. The patterns in Δt are interpreted to reflect the presence of the two major tectonic components involved in the Paleozoic Tasman margin in Australia (cf., Münker, 2000): subducting proto-Pacific crust (Δt >150 Myr), and Proterozoic Australia crust (Δt < 50 Myr) on the over-riding plate. Proterozoic Australia crustal sources are interpreted to dominate the western parts of the Tasman Element and Proterozoic crust further to the west, whereas Pacific crustal sources are inferred to characterise western Tasmania and much of the eastern part of the Tasman Element. Contrasts in Δt between the Cambrian Mount Read Volcanics in western Tasmania and similar aged rocks in western Victoria and New South Wales make direct tectonic correlation between these rocks problematic

Late pleistocene sedimentation history of the Shirshov Ridge, Bering Sea

The analysis of the lithology, grain-size distribution, clay minerals, and geochemistry of Upper Pleistocene sediments from the submarine Shirshov Ridge (Bering Sea) showed that the main source area was the Yukon–Tanana terrane of Central Alaska. The sedimentary materials were transported by the Yukon River through Beringia up to the shelf break, where they were entrained by a strong northwestward-flowing sea current. The lithological data revealed several pulses of ice-rafted debris deposition, roughly synchronous with Heinrich events, and periods of weaker bottom-current intensity. Based on the geochemical results, we distinguished intervals of an increase in paleoproductivity and extension of the oxygen minimum zone. The results suggest that there were three stages of deposition driven by glacioeustatic sea-level fluctuations and glacial cycles in Alaska

ІМІТАЦІЙНА МОДЕЛЬ ДЛЯ ОЦІНЮВАННЯ РИЗИКУ ТА МОЖЛИВИХ НАПРЯМКІВ ЗАВДАННЯ УДАРІВ БЕЗПІЛОТНИМИ ЛІТАЛЬНИМИ АПАРАТАМИ ПО ОБ’ЄКТАХ, ЩО ОХОРОНЯЮТЬСЯ

The most important features of the drone (unmanned aerial vehicle) are its survivability, noise immunity and secrecy. In this context, the threats that arise during the protection of weapons depots and important public facilities have been analyzed. The parameters of the early detection of drone attacks have been studied. The possibilities of countering the unmanned aircraft attack by means of air defense and electronic warfare systems are considered. In the geographic information system for an electronic map of the area, a simulation model is proposed. The model has an aircraft route organizer that allows analyzing possible flight directions at given altitudes and speeds on various route segments. With fixed initial conditions and repeated model execution, a statistically significant result can be obtained in the form of a mathematical probability of defeat (neutralization) of an unmanned aerial vehicle. This feature is implemented using the definition in the model of the states and events of an unmanned aerial vehicle along segments of the route. For example, a  case when the device enters the zone of action of one or more air defense means. Or, an example of another situation, when the drone with a certain probability is affected by air defense units. In the model it is possible to calculate and correct the probabilities of detection, neutralization and hitting of the drones.If in the process of the simulation model re-running, negative results in covering the objects are obtained, then the locations of observation points, electronic warfare and anti-aircraft defense facilities should be changed. The newly formed detection, cover and defeat zones should ensure the neutralization of the UAV in a potentially dangerous direction. In addition, on the base of results of the model, this approach can be used for the protection of other electronic warfare and air defense systems with higher likelihood of destruction and neutralization of the drones.Розглянуто особливості застосування ударного безпілотного літального апарата (БПЛА) та проаналізовано загрози, які виникають під час охорони складів озброєння та важливих державних об’єктів. Для електронної карти місцевості розроблено імітаційну модель, за допомогою якої може бути отриманий статистично значущий результат у вигляді математичного сподівання оцінки ступеня ураження (нейтралізації) БПЛА за умов багаторазового її виконання

The Grain Dynamics in a Region of an Ionized Hydrogen

We consider a grain dynamics in a region of ionized hydrogen around a massive star for estimating a time of setting a grain terminal velocity. We determine the applicability limits for the terminal velocity approximation for evolutionary models of ionized hydrogen regions that take into account a relative motion of dust and gas. For that purpose, we solve numerically the equation of motion for dust grains of several kinds typical for massive star forming regions.Работа посвящена изучению динамики пылинок в областях ионизованного водорода около массивных звезд с целью оценки времени достижения пылинками терминальной скорости. Определены границы применимости приближения терминальной скорости в эволюционных моделях областей ионизованного водорода с учетом движения пылинок относительно газа. Для этого проводится численное интегрирование уравнения движения для пылинок различных типов, характерных для областей образования массивных звезд