Astrokit -- an Efficient Program for High-Precision Differential CCD Photometry and Search for Variable Stars

Having a need to perform differential photometry for tens of thousands stars in a several square degrees field, we developed Astrokit program. The software corrects the star brightness variations caused by variations of atmospheric transparency: to this end, the program selects for each star an individual ensemble of reference stars having similar magnitudes and positions in the frame. With ten or more reference stars in the ensemble, the differences between their spectral types and the spectral type of the object studied become unimportant. Astrokit searches for variable stars using Robust Median Statistics criterion, which allows candidate variables to be selected more efficiently than by analyzing the standard deviation of star magnitudes. The software allows very precise automatic analysis of long inhomogeneous sets of photometric observations of a large number of objects to be performed, making it possible to find "hot Jupiter" type exoplanet transits and low-amplitude variables. We describe the algorithm of the program and the results of its application to reduce the data of the photometric sky survey in Cygnus as well as observations of the open cluster NGC188 and the transit of the exoplanet WASP-11 b / HAT-P-10 b, performed with the MASTER-II-URAL telescope of the Kourovka Astronomical Observatory of the Ural Federal University.Comment: to be published in Astrophysical Bulletin, Vol. 69, No.

Discovery of an unusual bright eclipsing binary with the longest known period: TYC 2505-672-1 / MASTER OT J095310.04+335352.8

We report on the MASTER Global Robotic Net discovery of an eclipsing binary, MASTER OT J095310.04+335352.8, previously known as unremarkable star TYC 2505-672-1, which displays extreme orbital parameters. The orbital period P=69.1 yr is more than 2.5 times longer than that of epsilon-Aurigae, which is the previous record holder. The light curve is characterized by an extremely deep total eclipse with a depth of more than 4.5 mag, which is symmetrically shaped and has a total duration of 3.5 yrs. The eclipse is essentially gray. The spectra acquired with the Russian 6 m BTA telescope both at minimum and maximum light mainly correspond to an M0-1III--type red giant, but the spectra taken at the bottom of eclipse show small traces of a sufficiently hot source. The observed properties of this system can be better explained as the red giant eclipsed by a large cloud (the disk) of small particles surrounding the invisible secondary companion.Comment: 8 figures, 9 pages, Astronomy and astrophysics in prin

Modern approaches for extraterrestrial matter collection

Представлены результаты работы, направленной на повышение эффективности поиска внеземного вещества с использованием методов наблюдательной астрономии. Описываются методика проведения наблюдений, принципы построения болидной сети и особенности ее организации. Обсуждаются вопросы сбора вещества в холодных и горячих пустынях.We present results of the activity aimed at increase in search efficiency of extraterrestrial matter collection, using methods of observational astronomy. Approaches for observations and technical features of appropriate fireball network structure are described. Results of traditional meteorite collection in cold and hot deserts with accumulation mechanisms are compared to modern methods.Работа выполнена в рамках государственного задания ФАНО России (тема «Деформация», №01201463327), проекта УрО РАН №15-17-2-11 при финансовой поддержке Министерства образования и науки Российской Федерации (базовое финансирование по проекту № 5162) и Правительства Российской Федерации (постановление №211, контракт №02.А03.21.0006)

Optical polarization observations with the MASTER robotic net

We present results of optical polarization observations performed with the MASTER robotic net for three types of objects: gamma-ray bursts, supernovae, and blazars. For the Swift gamma-ray bursts GRB100906A, GRB110422A, GRB121011A, polarization observations were obtained during very early stages of optical emission. For GRB100906A it was the first prompt optical polarization observation in the world. Photometry in polarizers is presented for Type Ia Supernova 2012bh during 20 days, starting on March 27, 2012. We find that the linear polarization of SN 2012bh at the early stage of the envelope expansion was less than 3%. Polarization measurements for the blazars OC 457, 3C 454.3, QSO B1215+303, 87GB 165943.2+395846 at single nights are presented. We infer the degree of the linear polarization and polarization angle. The blazars OC 457 and 3C 454.3 were observed during their periods of activity. The results show that MASTER is able to measure substantially polarized light; at the same time it is not suitable for determining weak polarization (less than 5%) of dim objects (fainter than 16$^m$). Polarimetric observations of the optical emission from gamma-ray bursts and supernovae are necessary to investigate the nature of these transient objects.Comment: 31 pages, 12 figures, 4 tables; Exposure times in Table 2 have been correcte

First results of the Kourovka Planet Search: discovery of transiting exoplanet candidates in the first three target fields

We present the first results of our search for transiting exoplanet candidates as part of the Kourovka Planet Search (KPS) project. The primary objective of the project is to search for new hot Jupiters which transit their host stars, mainly in the Galactic plane, in the $R_c$ magnitude range of 11 to 14 mag. Our observations were performed with the telescope of the MASTER robotic network, installed at the Kourovka astronomical observatory of the Ural Federal University (Russia), and the Rowe-Ackermann Schmidt Astrograph, installed at the private Acton Sky Portal Observatory (USA). As test observations, we observed three celestial fields of size $2\times2$ deg$^2$ during the period from 2012 to 2015. As a result, we discovered four transiting exoplanet candidates among the 39000 stars of the input catalogue. In this paper, we provide the description of the project and analyse additional photometric, spectral, and speckle interferometric observations of the discovered transiting exoplanet candidates. Three of the four transiting exoplanet candidates are most likely astrophysical false positives, while the nature of the fourth (most promising) candidate remains to be ascertained. Also, we propose an alternative observing strategy that could increase the project's exoplanet haul.Comment: 11 pages, 16 figures; Accepted for publication in Monthly Notices of the Royal Astronomical Society 201

Dissipative Dynamics of Polymer Phononic Materials

Phononic materials are artificial composites with unprecedented abilities to control acoustic waves in solids. Their performance is mainly governed by their architecture, determining frequency ranges in which wave propagation is inhibited. However, the dynamics of phononic materials also depends on the mechanical and material properties of their constituents. In the case of viscoelastic constituents, such as most polymers, it is challenging to correctly predict the actual dynamic behavior of real phononic structures. Existing studies on this topic either lack experimental evidence or are limited to specific materials and architectures in restricted frequency ranges. A general framework is developed and employed to characterize the dynamics of polymer phononic materials with different architectures made of both thermoset and thermoplastic polymers, presenting qualitatively different viscoelastic behaviors. Through a comparison of experimental results with numerical predictions, the reliability of commonly used elastic and viscoelastic material models is evaluated in broad frequency ranges. Correlations between viscous effects and the two main band-gap formation mechanisms in phononic materials are revealed, and experimentally verified guidelines on how to correctly predict their dissipative response are proposed in a computationally efficient way. Overall, this work provides comprehensive guidelines for the extension of phononics modeling to applications involving dissipative viscoelastic materials.</p

Eclesiásticos criollos en la Capilla Real de Palacio: una elite de poder en el reinado de Carlos II (1665-1700)

The present work analyzes the motives and reasons that lead the Creole elites of the American viceroyalties to request employment as honor chaplains and preachers in the King’s Royal Chapel during the final decades of the 17th century. This study also analyzes the selection mechanisms that were established by the Crown to facilitate the access to the institution, particularly those related to racial purity and nobility of the lineage of the applicants to one of those positions.El presente artículo analiza las razones que llevaron a las elites criollas de los virreinatos americanos a solicitar empleos de capellanes de honor y de predicadores reales en la Capilla Real de Palacio en las décadas finales del siglo XVII, así como el estudio de los mecanismos de selección establecidos por la Corona para facilitar su acceso a la institución, especialmente los relacionados con la limpieza y nobleza del linaje de los aspirantes a una de esas plazas

Measurement of the Muon Decay Parameter delta

The muon decay parameter delta has been measured by the TWIST collaboration. We find delta = 0.74964 +- 0.00066(stat.) +- 0.00112(syst.), consistent with the Standard Model value of 3/4. This result implies that the product Pmuxi of the muon polarization in pion decay, Pmu, and the muon decay parameter xi falls within the 90% confidence interval 0.9960 < Pmuxi < xi < 1.0040. It also has implications for left-right-symmetric and other extensions of the Standard Model.Comment: Extended to 5 pages. Referee's comments answere

Registration of the quantum state of a single photon to create a satellite quantum network

Artificial satellites employed as trusted nodes can increase the distance between two parties to establish quantum key distribution (QKD), unlike fiber based communication lines that are limited up to a few hundred kilometers. This report summarises our progress on a ground receiver for satellite QKD and its tracking receiving system (TRS). The authors demonstrate the operation of the TRS in practice and achieve standard tracking error of 1.4/Ltrad observing four satellites over 80% of the time they were available. The optical signal, which was the sunlight reflected of low Earth orbit satellites, was attenuated to a single photon level and was detected effectively using avalanche single photon detectors. The authors have thus proved that the developed system is capable of stable reception of quantum signal from a satellite. © Published under licence by IOP Publishing Ltd.This work is supported by Russian Science Foundation (grant No. 17-71-20146)