New atlas of open star clusters

Due to numerous new discoveries of open star clusters in the last two decades, astronomers need an easy-to-use resource to get visual information on the relative position of clusters in the sky. Therefore we propose a new atlas of open star clusters. It is based on a table compiled from the largest modern cluster catalogues. The atlas shows the positions and sizes of 3291 clusters and associations, and consists of two parts. The first contains 108 maps of 12 by 12 degrees with an overlapping of 2 degrees in three strips along the Galactic equator. The second one is an online web application, which shows a square field of an arbitrary size, either in equatorial coordinates or in galactic coordinates by request. The atlas is proposed for the sampling of clusters and cluster stars for further investigation. Another use is the identification of clusters among overdensities in stellar density maps or among stellar groups in images of the sky. © 2017 A. F. Seleznev et al.Acknowledgment: The work of Anton F. Seleznev was partly supported by the Ministry of Education and Science (the basic part of the State assignment, RK no. AAAA-A17-117030310283-7). The work of Anton F. Seleznev and of Eka-terina Avvakumova was supported also by the Act no. 211 of the Government of the Russian Federation, agreement no. 02.A03.21.0006. Authors are very grateful to Tatiana Selezneva for the graphic design of the web application

Optical AR coatings of the Mid-IR band for ZnGeP2 single crystals based on ZnS and oxide aluminum

In this work, the parameters of antireflection interference coatings based on alternating layers of ZnS/Al2O3 on the laser-induced damage threshold (LIDT) of ZGP crystals under the action of Ho:YAG laser radiation at a wavelength of 2.097 μm were determined. The coating deposition was carried out using the ion-beam sputtering method. The LIDT of the sample with a coating based on alternating layers ZnS and Al2O3 was equal to WEo = 3.45 J/cm2, and the LIDT of the uncoated sample was equal to WEo = 2.23 J/cm2. An increase in the optical breakdown threshold by ~55% was observed after the deposition of an AR coating based on ZnS and Al2O3 materials. An assumption was made about the absence of local fluctuations in the composition and mechanical stresses in the case of the coated sample, namely that this leads to good adhesion of the multilayer coating to the polished surface of the crystal, and as a result to an increase in the optical breakdown threshold as compared to the uncoated sample due to closure of the dangling chemical bonds and bulk defects emerging on the polished surface

HYSTERESIS PROPERTIES AND MAGNETIZATION REVERSAL IN FeMn/FM (FM=Co, Fe, Ni, FeNi) FILMS WITH EXCHANGE BIAS

Angular dependencies of hysteresis properties of various ferromagnetic layers exchange coupled to a pinning antiferromagnetic layer have been investigated experimentally. The re-sults have been interpreted and analyzed in detail using macrospin approximation and micro-magnetic simulation.This work was supported by the Russian Science Foundation (project No 19-72-00141)

Contribution of Unresolved Binary Stars to Radial Velocity Dispersion of Star Cluster

Рассмотрена задача об изменении дисперсии лучевых скоростей звезд скопления, если в выборке присутствуют неразрешенные двойные звезды, в спектрах которых видны линии только главного компонента. В работе моделируется распределение лучевых скоростей главного компонента для заданных распределений элементов орбит. С помощью этого распределения исследуется зависимость относительной дисперсии лучевых скоростей от доли двойных в скоплении. Полученная зависимость аппроксимируется логарифмической зависимостью. Обсуждаются пределы применимости этой эмпирической зависимости.We consider the problem of changing of the radial velocity dispersion of the cluster stars if the sample contains unresolved binary stars whose spectra show lines of only the primary component. We simulate the distribution of radial velocities of the main component for specified distributions of orbital elements. This distribution is used to study the dependence of the relative radial velocity dispersion on the fraction of binaries in the cluster. The resulting dependence is described by the logarithmic function. Restrictions of the application of this empirical dependence are discussed.Работа выполнена при финансовой поддержке Министерства науки и высшего образования Российской Федерации, тема FEUZ-2023-0019

Comparison of the Open Cluster Luminosity Functions by the Data of 2MASS and Gaia DR2

Luminosity functions of open clusters NGC 1912, NGC 2099, NGC 6834, NGC 7142, IC 2714 are obtained with the kernel density estimator. We used Gaia DR2 data for this. Three different luminosity functions have been obtained for each cluster with the different level of selection using the Gaia DR2 parallaxes and proper motions. These results are compared with other in order to determine the cluster star number, which have been rejected during selection. We also compare the results with the luminosity functions obtained by 2MASS data.Функции блеска рассеянных скоплений NGC 1912, NGC 2099, NGC 6834, NGC 7142, IC 2714 построены методом “kernel density estimator”. Для построения были использованы данные каталога Gaia DR2. Для каждого скопления построены три функции блеска с разной степенью отбора по представленным в DR2 параллаксам и собственным движениям. Полученные результаты сравниваются друг с другом для определения числа звезд скопления, отброшенных при отборе, а также с функциями блеска, рассчитанными по данным 2MASS

Method for determination of cluster radius from radial density profile

Представлен численный метод определения радиуса звездного скопления с помощью радиального профиля поверхностной плотности. Метод реализует алгоритм глазомерной оценки, но минимизирует субъективность, его результаты хорошо согласуются с глазомерными оценками радиуса рассеянного скопления NGC 2516.We propose the numerical method for determining the radius of a star cluster using its radial surface density profile. The method realizes the algorithm of an eye estimate but minimizes a subjectivity; its result is in a good agreement with the eye estimate of the radius for the open cluster NGC 2516.Работа выполнена при финансовой поддержке Министерства науки и высшего образования Российской Федерации, тема No. FEUZ–2020–0030

Comparison of the results of star counts in nine open star clusters by the data of 2MASS and Gaia DR1

Звездные подсчеты с помощью метода kernel estimator проведены для скоплений NGC 1912, NGC 2099, NGC 4052, NGC 5715, NGC 6268, NGC 6834, NGC 7142, IC 2714, Czernik 38. Для подсчетов были использованы данные каталога Gaia DR1. Полученные результаты сравниваются с результатами звездных подсчетов по данным каталога 2MASS.Star counts were carried out for the clusters NGC 1912, NGC 2099, NGC 4052, NGC 5715, NGC 6268, NGC 6834, NGC 7142, IC 2714, Czernik 38 with the use of kernel estimator by Gaia DR1 data. Results are compared with the results of star counts by 2MASS data.Часть работ проведена при финансовой поддержке государства в лице Министерства образования и науки Российской Федерации (базовая часть госзадания, РК №AAAA-A17-117030310283-7), а также при финансовой поддержке Правительства РФ (постановление №211, контракт №02.A03.21.0006)

Structural and dynamical characteristics of nine open star clusters

В рамках проекта по созданию однородного каталога структурных и динамических характеристик рассеянных звездных скоплений звездные подсчеты с помощью метода kernel estimator проведены для скоплений NGC 1912, NGC 2099, NGC 4052, NGC 5715, NGC 6268, NGC 6834, NGC 7142, IC 2714, Czernik 38. Для подсчетов были использованы данные каталога 2MASS. Для скоплений выборки построены карты распределения и радиальные профили поверхностной плотности, получены оценки функций светимости и функций масс, определены положения центров, получены оценки радиусов, чисел звезд и масс скоплений.Within the framework of the project of a development of the uniform catalog of structural and dynamical characteristics of open star clusters, star counts were carried out for the clusters NGC 1912, NGC 2099, NGC 4052, NGC 5715, NGC 6268, NGC 6834, NGC 7142, IC 2714, Czernik 38 with the use of kernel estimator by 2MASS data. Two-dimensional maps and radial profiles of a surface density, estimates of luminosity functions and mass functions have obtained for the sample clusters. The positions of cluster centres and estimates of the cluster radii, number of stars and masses have been determined.Часть работ проведена при финансовой поддержке государства в лице Министерства образования и науки Российской Федерации (базовая часть госзадания, РК № AAAA-A17-117030310283-7), а также при финансовой поддержке Правительства РФ (постановление № 211, контракт № 02.A03.21.0006)

Volitional self-regulation and emotional burnout of professional sambo-athletes who suffered from sports injuries

Objective: to study the level of volitional self-regulation and emotional burnout in male sambo-athletes who underwent sports injuries of various degrees of severity. Materials and methods: 60 male sambo-athletes were examined. They were divided into 3 groups of 20 people in each group based on types of sports injuries. Results: significantly (p=0.001) lower level of volitional self-regulation was found in the third group who underwent more injuries (total scale: Q1=6,0; Me=8,0; Q3=10,0; «perseverance»: Q1=5,0; Me=5,5; Q3=8,0; «self-control»: Q1=4,0; Me=4,5; Q3=5,0). More pronounced emotional burnout occured in athletes who had more injuries (Q1=64,5; Me=69,0; Q3=71,0; p=0,001). Inadequate emotional response and emotional and moral disorientation was leveled down with aggravation of the severity of injuries (Q1=25,0; Me=44,0; Q3=61,0; p=0,039). Adaptation systems strain is manifested by a marked emotional exhaustion and decrease in volitional self-regulation with an increase in the number of injuries. Conclusions: if incidence and severity of injuries increases in sambo-athletes the level of volitional self-regulation reduces and emotional burnout occurs, which is characterized by the stress of the system of psychological adaptation

Magnetic properties of Co-W thin films

In this paper, the magnetic properties and structure of the Co-W films of different compositions prepared by magnetron sputtering on glass substrates without and with Ta or Ru buffer layers were investigated. The dependences of coercive force on the W content for the studied films were non-monotonic. The peak value of the coercive force of about 400 Oe was observed for the films on glass and Ta layers with W content of 8-9 at. %. The films deposited on Ru layers had a coercive force of 4 times less, and it was practically independent of the W content in a wide range from 6 to 20 at. %. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-72-10044This work was carried out under the financial support by the RSF grant, project No. 18-72-10044