Odessa Astronomical Publications最新文献

{"title":"SPECTRAL STUDY LOWER SOLAR ATMOSPHERE OF THE ACTIVE REGION SITE WITH THE ELLERMAN BOMB AND ACCOMPANYING Hα-EJECTIONS","authors":"M. Pasechnik","doi":"10.18524/1810-4215.2023.36.290217","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290217","url":null,"abstract":"The results of studying in details the features formation and development of the Ellerman bomb (EB) and accompanying Hα-ejections arose on the NOAA 11024 active region site, are presented. This site was in the region of emerging new magnetic flux. Spectral data with high spatial and temporal resolution were obtained with the French–Italian solar telescope THEMIS on July 4, 2009. Spectra with the Hα line and with the spectral region λλ ≈ 630 nm were used. Stokes I profiles were obtained with an interval corresponding to 160 km on the Sun surface.\u0000The Hα line profiles obtained for different periods of EB development were asymmetric with an excess of emission in the short-wavelength wing. The temporal variations of intensity in the Hα line wings at distances ±0.1 and ±0.16 nm from its center indicated that two periods can be distinguished in EB evolution: the preheating phase and the flaring phase, during which the gradual and pulse energy release occurred.\u0000Hα-ejections (surges) are small-scale eruptions of cold matter in the solar atmosphere. In all spectra they were visible in the absorption. The surge profiles were projected onto the blue or red Hα line wing. Its Doppler shifts were used to calculate the line-of-sight velocities (Vlos) of chromospheric matter in surges. The velocity distribution in the surges indicated their multi-flow structure. One of the surges showed signs of plasma vortex motions. Most surges occurred with a high velocity – Vlos up reached -110 km/s, and down to 90 km/s.\u0000We obtained temporal Vlos variations in a wide interval (140 ─ 490 km) of photospheric heights for the area of EB development and its immediate surroundings. At all photospheric levels predominantly upward motions were found. In the central part of the EB in the upper layer of the photosphere the Vlos varied between -0.5 ÷ 0.2 km/s, in the lower layer – -1.1 ÷ -0.1 km/s. An increase the core intensity of all photospheric lines was correlated in time with an increase of the emission intensity in the Hα line wings.\u0000The new observational data for the Ellerman bomb and accompanying Hα-ejections, which have been obtained and analyzed, can be used to verify existing and create new theoretical models.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"43 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE LONG-TERM OBSERVATIONS OF THE POWER COSMIC RADIO SOURCES ON THE RADIO TELESCOPE URAN-4 AT THE DECAMETER WAVE RANGE","authors":"O. A. Lytvynenko, S. Panishko, V. G. Derevyagin","doi":"10.18524/1810-4215.2023.36.290139","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290139","url":null,"abstract":"The radio telescope (RT) URAN-4, located near the city of Odessa, started to work in 1987 as a component of the radio interferometric system URAN, which operates in the decameter range of radio waves and whose elements are placed in several points throughout Ukraine. The first successful VLBI observations of compact cosmic radio sources in the URAN system were carried out on the RT URAN-4–UTR-2 interferometer at the end of 1987. In the same period, a program was launched for regular observations of powerful cosmic radio sources 3C 144, 3C 274, 3C 405, 3C 461 at frequencies of 20 and 25 MHz in the radiometric mode.\u0000Later, several stages of modernization of radiometric equipment and systems for automation of observations took place. This made it possible by 2000 to switch to practically continuous radiometric monitoring of a group of these radio sources. Method of measuring and processing of the records of the radio sources passage through RT direction pattern, statistics of the observation records on time periods in dependence on the registration systems of the data obtained during more 35 years observations on the RT URAN-4 are considered in this paper. Some results are given which related to the study of the flux densities of the observing radio sources and ionospheric scintillation effect which is essential at the decameter wavelength range.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"224 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TEST OPTICAL OBSERVATIONS OF THE COSMOS 1408 FRAGMENTS","authors":"O. Kozhukhov, Y. V. Omelchenko, D. Kozhukhov, O. G. Solomakha, M. V. Kulichenko, O. Shulga, Y. Kozyryev, N. Maigurova","doi":"10.18524/1810-4215.2023.36.290222","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290222","url":null,"abstract":"The non-functioning spacecraft COSMOS 1408 (NSSDCA/COSPAR ID: 1982-092A) was destroyed as a result of tests involving Russian anti-satellite weapons on 15 November 2021. This led to the creation of a significant debris cloud that poses a threat to other objects in low Earth orbit (LEO), particularly those in close orbits. More than 1500 of these fragments reached trackable sizes. Such events require rapid and immediate monitoring through all available ground tracking means, including radar and optical observation. The following study presents the results of optical observations of the selected fragments of COSMOS 1408 in Ukraine. These observations were carried out by the telescope OES30 from the National Space Facilities Control and Test Center of the State Space Agency of Ukraine and the Fast Robotic Telescope (FRT) of the Research Institute \"Mykolaiv Astronomical Observatory\" in February 2022. The observations demonstrated that Ukrainian optical sensors are capable of tracking LEO space debris objects with radar cross-sections (RCS) less than 0.1 square meters when relatively accurate ephemeris data is available. The astrometric reduction has been performed for the acquired frames with fragments of the satellite, which revealed that orbital parameters of a significant part of the targeting objects were close to the orbital parameters of the original satellite before the event. Furthermore, the results of processing the available observations indicated that the range of apogee heights significantly exceeds the range of perigee heights. These findings align with conclusions drawn by previous researchers. In the future, it will be essential to assess the capabilities of sensors for observing the aftermath of object destruction in LEO, especially during the initial hours and days following such events when precise debris orbit data may be lacking.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"181 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DECAMETER TYPE IV BURST WITH UNUSUAL HIGH POLARIZATION","authors":"V. Melnik, A. Brazhenko, A. V. Frantsuzenko, V. Dorovskyy, M. Shevchuk","doi":"10.18524/1810-4215.2023.36.290136","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290136","url":null,"abstract":"We present results of observations of Type IV burst with unusual high polarization equalled in maximum phase about 100%. This burst was registered both by URAN-2 and NDA radio telescopes on 13 July 2022. It continued for about 5 hours and consisted of sub-bursts with high frequency drift rates and had short durations. We associate it with the weak CME, which propagated in the East direction in the form of thread-like structure. Theoretical description of sub-burst in the plasma mechanism of radio emission allow explaining their high polarization, high drift rates and short durations.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"122 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DIRECT IMAGE RECONSTRUCTION IN MULTI-ELEMENT INTERFEROMETRY","authors":"A. Lozynskyy, O. Ivantyshyn, B. P. Rusyn","doi":"10.18524/1810-4215.2023.36.290123","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290123","url":null,"abstract":"The Ukrainian VLBI system of decameter radio telescopes URAN successfully solves many scientific problems, but implementing aperture synthesis technology has a number of difficulties. One of them is significant phase distortions in this range caused by an inhomogeneous propagation environment. Therefore, the task arose to develop an alternative technology with the conventional name \"Interferovision\", which would allow us to restore radio images with a limited number of antennas, operate with broadband signals, not require flatness of the objects scene, and have an extended field of view.\u0000A method of direct image reconstruction when observing objects in space, using a multi-element interferometer, is proposed. This method is based on a physically based principle that is similar to holography. The wave front is registered by the antennas of the interferometer, and further processing is equivalent to its playback in reverse and registration of the resulting spatial interference image. There are no special requirements for the radiation of individual points of the source, except for its delta correlation. A finite frequency band is considered, and each point can be characterized by its own spectrum, that is, its own autocorrelation function of radiation. The resolution of the direct reconstruction method depends on its width. With the quasi-monochromatic approximation, the autocorrelation functions of the radiation of all the source points degenerate into sinusoids, and the restoration of the image becomes possible only with the use of the Fourier transformation. A theoretical justification of the method for spaces of different dimensions has been obtained. Interferometric systems of the same rank with many antennas are reduced to a same canonical form with fixed number of virtual antennas placed at the origin of the coordinates and at unit distances on the coordinate axes. The ambiguity of the obtained solution is eliminated by using an additional antenna.\u0000A simulation of the proposed method of direct image reconstruction for two-dimensional space was carried out. Despite the low conditionality of the system for estimating the distance, when it increases, the angular characteristics are preserved. Therefore, the method is promising for restoring radio images of space radio sources.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"7 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A NEW METHOD OF INVESTIGATION OF THE ORIENTATION OF GALAXIES IN CLUSTERS IN LACK OF INFORMATION ABOUT THEIR MORPHOLOGICAL TYPES","authors":"B. Mrzygłód, W. Godłowski","doi":"10.18524/1810-4215.2023.36.289772","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.289772","url":null,"abstract":"The problem of the formation of structures in the universe is one of the most important issues of modern extragalactic astronomy and cosmology. The tool enabling the verification of a particular formation scenario is analysis the spatial orientation of the galaxies from deprojection of their images. Obtaining correct analysis results obliges to take into account the fact that galaxies are oblate spheroids with the real axis ratio depending on the morphological type, which, however, is not given in most of the currently available astronomical data. According to the approach used in the new method of investigation, on the basis of estimated frequencies of occurrence of given morphological types, obtained using sufficiently numerous observational data, simulations are performed, which enable to recognize new angle distributions used in orientation studies. These distributions already contain information on the frequency of the appearance of galaxies of particular morphological types in clusters, allowing for more accurate results of the statistical tests carried out during the analysis. The method is an extension of results developed in Godłowski 2012 and Pajowska et al. 2019.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"230 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"COMPARATIVE ANALYSIS OF MAGNETIC STORMS IN THE ODESSA MAGNETIC ANOMALY REGION WITH PLANETARY AND IONOSPHERIC STORMS DURING THE MONITORING PROGRAM AT RT \"URAN-4\" (1987 – 2010)","authors":"L. Sobitnyak, M. Ryabov, M. Orlyuk, A. Sukharev, D. M. Ryabov, A. Romenets, Yu. Sumaruk","doi":"10.18524/1810-4215.2023.36.290585","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290585","url":null,"abstract":"This work is a continuation of the study of the response of the Odesa geomagnetic anomaly to the manifestations of solar and planetary geomagnetic activity. Not far from the territory of this magnetic anomaly there is the geomagnetic observatory \"Odesa\" and the decameter radio telescope \"URAN-4\" of the RI NASU. A catalogue of magnetic storms for the period 1987-1994 and 2000-2009 was compiled for the monitoring program of high-power space radio sources at RT \"URAN-4\" using the database of the geomagnetic observatory \"Odesa\". In this paper, a comparative analysis of the features of the manifestations of geomagnetic storms in the zone of the Odesa magnetic anomaly, planetary storms and ionospheric storms in the 22nd and 23rd cycles of solar activity is carried out. The main results are as follows. The magnetic anomaly amplifies the effects of regional manifestations of planetary magnetic storms. The number of different types of magnetic storms and the dynamics of their changes in the Odesa anomaly differ significantly in the 22nd and 23rd cycles of solar activity. Comparisons have shown that the duration of magnetic storms in the Odessa anomaly is longer than the duration of planetary magnetic and ionospheric storms. According to the data of the «URAN-4» radio telescope, geomagnetic storms form various manifestations of the effects of ionospheric flickers and flux changes for space radio sources depending on the time of their observations. For the region of the Odesa geomagnetic anomaly, such comprehensive studies have not been carried out before. The conducted studies will become an important basis for understanding the influence of magnetic anomalies on the dynamics of the ionosphere during periods of solar and geomagnetic activity.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"53 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139011997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE STUDY OF X-RAY SPECTRUM OF COMA GALAXY CLUSTER","authors":"L. Zadorozhna, A. Tugay, O. Prikhodko, D. Malyshev, Y. Sahai, D. Savchenko, N. Pulatova","doi":"10.18524/1810-4215.2023.36.289971","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.289971","url":null,"abstract":"The X-ray spectrum of the Coma galaxy cluster was studied using the data from the XMM-Newton observatory. We combined 7 observations performed with the MOS camera of XMM-Newton in the 40′ × 40′ region centered at the Coma cluster. The analyzed observations were performed in 2000–2005 and have a total duration of 196 ksec. We focus on the analysis of the MOS camera spectra due to their lower affection by strong instrumental line-like background. The obtained spectrum was fitted with a model including contributions from the Solar system/Milky Way hot plasma and a power law X-ray background. The contribution of the instrumental background was modeled as a power law (not convolved with the effective area) and a number of Gaussian lines. The contribution from the Coma cluster was modeled with a single-temperature hot plasma emission. In addition, we searched for possible non-thermal radiation present in the vicinity of the center of the Coma cluster, originating e.g. from synchrotron emission of relativistic electrons on a turbulent magnetic field. We compared the results with previous works by other authors and spectra obtained from other instruments that operate in the similar energy range of 1−10 keV. Careful and detailed spectrum analysis shall be a necessary contribution to our future work – searching for axion-like dark matter particles’ manifestations in the Coma cluster.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"183 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SOLAR AND GEOMAGNETIC ACTIVITY IN 19-25 CYCLES","authors":"T. Sumaruk, P. V. Sumaruk, A. Neska","doi":"10.18524/1810-4215.2023.36.288658","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.288658","url":null,"abstract":"The paper presents the results of the analysis of changes solar and geomagnetic activity in 19−25 Wolf cycles. A forecast of the maximum geomagnetic activity cycle 25 is made.\u0000Solar activity is presented by sunspot number RZ, geomagnetic activity is expressed by the energetic index calculated from the data of the \"Lviv\" and \"Belsk\" geomagnetic observatories. By annual averages RZ values, the 11-year window was used to obtain the solar activity minimum (around 1711, 1810, 1901, and 2009). The minimum of 2009 was one of the smallest in the observed data, and we took it as the beginning of the 24th cycle and the 100-year solar activity cycle. The maximum of the 24th cycle occurred in 2014 for RZ and in 2015 for energetic index.\u0000Cycle 25 began in 2019 according to RZ, and in 2020 cording to energetic index. For cycles 19−25 solar activity is 1−2 years ahead of magnetic activity. The identified quasi-biennial variations over the studied period and the lag of geomagnetic activity from solar activity allow us to predict the magnitude of geomagnetic activity and its maximum in cycle 25.\u0000According to our calculations, the maximum of geomagnetic activity will occur around 2026 and its magnitude will be 1.5−2 times higher than the maximum of the 24th cycle.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"116 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ANGULAR STRUCTURE OF THE RADIO GALAXY 3C280 AT DECAMETER WAVELENGTHS","authors":"R. V. Vashchishyn, V. Shepeliev, O. A. Litvinenko, G. S. Podgorny, A. V. Lozynskyy","doi":"10.18524/1810-4215.2023.36.290189","DOIUrl":"https://doi.org/10.18524/1810-4215.2023.36.290189","url":null,"abstract":"The image of the 3C280 radio galaxy at decimeter wavelengths consists of two emission regions, the centers of which are separated by about 13 arc seconds. These regions are lobes of the radio galaxy with bright compact components or hot spots embedded in them. We present the results of a study of the source structure in the decameter wavelength range, carried out with the URAN-1 – URAN-4 radio interferometers using a especially technique developed. We show, that at the decameter wavelengths, the source model contains two extended components with the size and position as the lobes have in the decimeter range and a compact detail corresponding to one of the hot spots. The radio emission of other hot spots is not detected at the decameter waves due to their low flux density. The spectra of the radio galaxy components and their variation in the range from decameter to decimeter wavelengths are determined in this study. It is found, that extended lobes provide about 70% of 3C280 flux at low frequencies in contrast to the high-frequency image of the radio galaxy, where compact hot spots predominate in the source radiation.","PeriodicalId":34039,"journal":{"name":"Odessa Astronomical Publications","volume":"113 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}