Kinematics and Physics of Celestial Bodies最新文献

{"title":"Electron Density Reduction Caused by the Tonga Volcano Eruption on January 15, 2022","authors":"L. F. Chernogor,&nbsp;Yu. B. Mylovanov","doi":"10.3103/S0884591323040037","DOIUrl":"10.3103/S0884591323040037","url":null,"abstract":"<p>The explosive Tonga volcano is among the unique ones. Its order of magnitude is the same as Krakatoa (1883), St. Helens (1980), El Chichón (1982), and Pinatubo (1991) volcanoes. The uniqueness of the Tonga volcano lies in the fact that the products of eruption of the Tonga volcano rose to a record height of 50–58 km, whereas the height of eruption of the most powerful Krakatoa volcano reached only 40–55 km. The Tonga volcano has estimates of 3.9 × 10¹⁸ J for thermal energy, approximately 5.8 for volcanic explosive index <i>VEI</i>, approximately 5.5 for volcano magnitude <i>M</i>, and approximately 10.8 for eruption intensity <i>I</i>. We have estimated the explosion energy to be 16–18 Mt TNT. The problems of proving that a decrease in the total electron content (TEC), which was observed on January 15, 2022, in the ionosphere, was caused by the Tonga volcano explosion, and determining the principal parameters of the ionospheric hole are very urgent problems. This study is aimed at analyzing the parameters of the ionospheric hole created by the Tonga volcano explosion on January 15, 2022. Well-known GPS technologies are used to obtain data on time variations of the ionospheric TEC in the vertical column by measuring the pseudo-range and the integrated phase data at two frequencies along the path to each GPS satellite. The space weather conditions were favorable for observing the ionospheric effects caused by the explosion of the Tonga volcano. The calendar dates of January 13 and 17, which are used as reference days, were the least disturbed ones. The main results are as follows. It was found that the TEC on the reference days varied almost monotonically. Aperiodic and quasi-periodic variations of TEC were observed on the day of volcano eruption. Aperiodic variations are associated with a decrease in the TEC. This effect is called the ionospheric hole. It has been proven that the ionospheric hole is caused by a volcanic explosion. The delay time of the hole increases with an increase in the distance between the volcano and the observation site, while both the absolute value of the TEC and the relative value of its decrease are reduced. According to estimates, the horizontal size of the ionospheric hole did not exceed 10 Mm, and the time delay of its appearance did not exceed 122 min. The vertical speed of disturbance propagation was 36–72 m/s, and the horizontal speed was 2.2 km/s. The lifetime of the ionospheric hole was 120–200 min. The TEC in the ionospheric hole was reduced by approximately 2.5–10 TECU, which is a function of the distance from the volcano to the observation site, and the relative decrease ranged from –17 to –34%.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 4","pages":"204 - 216"},"PeriodicalIF":0.5,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4152956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global Variations of the Total Electron Content in the Equatorial Ionosphere during the Annular Solar Eclipse of June 21, 2020","authors":"L. F. Chernogor,&nbsp;Yu. B. Mylovanov","doi":"10.3103/S0884591323040025","DOIUrl":"10.3103/S0884591323040025","url":null,"abstract":"<p>A solar eclipse (SE) causes recordable disturbances in all subsystems of the Earth–atmosphere–ionosphere–magnetosphere system and in geophysical fields. The response of the system to an SE substantially depends on the eclipse magnitude, the solar cycle phase, the atmospheric and space weather, the season, the time, and the observation coordinates. Manifestations of the response are also influenced by the observation technique. Despite the fact that the effect of a solar eclipse on the ionosphere has been studied for approximately 100 years, a number of unresolved issues remain. The purpose of this study is to describe the results of our analysis of temporal total electron content (TEC) variations caused by the annular solar eclipse on June 21, 2020, in the equatorial ionosphere. The authors analyzed 132 time dependences of the TEC that covered an extensive region with an eclipse. The maximum magnitude (<i>M</i>_max = 0.9940) of the eclipse, which began at 06:39:59 UT, was observed in northern India in Uttarakhand and lasted 38 s. Space weather conditions on June 21, 2020, were favorable for studying the effects associated with the SE. To reveal the response of the ionosphere to the annular SE on June 21, 2020, the GPS signal recordings were processed. Time variations of the TEC in the ionosphere on reference days and on the SE day of June 21, 2020, were analyzed on a global scale. For this purpose, the results of measurements at twelve stations and eleven GPS satellites were used. The dependences of the absolute and relative TEC value decreases caused by the SE on a time of day are studied. The lowest value of the TEC decrease (–2…–3 TECU) was observed in the morning. In the daytime and in the evening hours, it reached –4…–6 TECU. The relative decrease in the TEC barely depended on a time of day and reached –30…–35%. No stable dependence of the TEC decrease on the eclipse magnitude was found. The relative value of the TEC decrease depended on the SE magnitude, i.e., smaller values of the SE magnitude corresponded to smaller values of the relative TEC decrease. The duration of the TEC reduction exceeded the duration of the eclipse by 1.5–2.5 h. The time of reaching the minimum TEC values in the daytime and the evening hours delayed by 10–20 min with respect to the time of reaching the maximum SE magnitude. Wave-like disturbances of the TEC were practically absent. Undisturbed TEC values and the TEC values disturbed by the eclipse substantially depended on the location of stations and the trajectory of satellites, which was associated with the influence of equatorial ionization anomaly. This is the main peculiarity of ionospheric effects of the SE at latitudes 0°–30° N.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 4","pages":"181 - 203"},"PeriodicalIF":0.5,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4153466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of GNSS Observations (GPS Weeks 1934–2105) for the Propagation of the IGS14 Reference Frame on the Territory of Ukraine","authors":"O. Khoda","doi":"10.3103/S0884591323030054","DOIUrl":"10.3103/S0884591323030054","url":null,"abstract":"<p>From January 29, 2017 to May 16, 2020 (GPS weeks 1934–2105) all products of the International GNSS Service (IGS)–precise ephemerides of GPS and GLONASS satellites, coordinates and velocities of permanent GNSS stations, etc.–were based on the IGS14 reference frame, the first IGS realization of the release of the International Terrestrial Reference Frame ITRF2014. Observations of GNSS satellites at permanent stations located in Ukraine and in the Eastern Europe for this period were processed in the GNSS Data Analysis Centre of the Main Astronomical Observatory NAS of Ukraine (MAO). The processing was carried out with the <i>Bernese GNSS Software ver. 5.2</i> according to the requirements of the EUREF Permanent GNSS Network (EPN), that were relevant at that time. In total, observations on 277 GNSS stations, including 205 Ukrainian stations belonging to the following operators of GNSS networks: MAO NAS of Ukraine, StateGeoCadastre of Ukraine (UPN GNSS), NU Lviv Polytechnic (GeoTerrace), PJSC System Solutions (System.NET), TNT TPI company (TNT TPI GNSS Network), Navigation and Geodetic Center (NGC.net), UA-EUPOS/ZAKPOS, E.P.S. LLC, Coordinate navigation maintenance system of Ukraine (NET.Spacecenter), Kiev Institute of Land Relations (KyivPOS), KMC LLC, were processed. The IGS14 reference frame was realized by applying No-Net-Translation conditions on the coordinates of the EPN Class A stations from the EPN C2100 catalogue. As result, the stations’ coordinates in the IGS14 reference frame and the zenith tropospheric delays for all stations were estimated. The mean repeatabilities for components of GNSS stations’ coordinates for all weeks (the characteristics of the precision of the obtained daily and weekly solutions) are in the following ranges: for the northern and eastern components – from 0.6 to 1.4 mm (average values are 0.93 and 1.00 mm respectively) with outliers for the eastern component of 2.02 and 1.55 mm for GPS weeks 2085 and 2091 respectively, for height component – from 2.0 to 5.5 mm (average value is 3.51 mm).</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 3","pages":"173 - 179"},"PeriodicalIF":0.5,"publicationDate":"2023-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4688488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photometric Flattening Index of the Solar Corona in the Solar Cycle","authors":"M. І. Pishkalo","doi":"10.3103/S0884591323030066","DOIUrl":"10.3103/S0884591323030066","url":null,"abstract":"<p>The photometric flattening index as a quantitative characteristic of the shape of the solar corona observed during a total solar eclipse was proposed by Ludendorff in the 1930s. The work collected the values of the flattening index for 69 total solar eclipses in 1851–2020 and investigated their relationship with the parameters of the solar cycle. The value of the flattening index varies from approximately 0.3–0.4 at the cycle minimum to 0.0–0.1 at the cycle maximum. The flattening index correlates with the relative sunspot numbers and the phase of the solar cycle. The correlation coefficients between the flattening index and the daily, monthly and smoothed monthly sunspot numbers are –0.577 (<i>р</i> &lt; 4 × 10^–7), –0.595 (<i>p</i> &lt; 8 × 10^–8) and –0.598 (<i>p</i> &lt; 7 × 10^–8), respectively. The correlation coefficients between the flattening index and the phase of the solar cycle for the rising and declining phases of the cycle are –0.759 (<i>p</i> &lt; 5 × 10^–6) and 0.660 (<i>p</i> &lt; 2 × 10^–6), respectively. The observed shape of the solar corona, in particular the value of the flattening index, is determined by the global magnetic field of the Sun, mainly by its dipole component.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 3","pages":"164 - 172"},"PeriodicalIF":0.5,"publicationDate":"2023-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4687174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LyC Galaxies with Ionizing Radiation Leakage: Properties in the Midinfrared Range Based on Data from the WISE Space Telescope","authors":"I. Yu. Izotova,&nbsp;Yu. I. Izotov","doi":"10.3103/S0884591323020022","DOIUrl":"10.3103/S0884591323020022","url":null,"abstract":"<p>The photometric characteristics in the midinfrared range of compact galaxies with ionizing radiation leakage (LyC galaxies) are studied to find relationships that would enable the quantitative assessment of the ionizing radiation that goes beyond the galaxy. In particular, the relationships between the color characteristics of galaxies according to data from the WISE space telescope and radiation fraction <i>f</i>_esc(LyC) in the Lyman continuum and radiation fraction <i>f</i>_esc(Ly_α) in the Ly_α line, which go beyond the galaxy, are investigated. The dependences of <i>f</i>_esc(LyC) and <i>f</i>_esc(Ly_α) on color index <i>W</i>1–<i>W</i>4 are established from the WISE space telescope data, where <i>W</i>1 and <i>W</i>4 are apparent stellar magnitudes at wavelengths of 3.4 and 22 μm, respectively. This makes color index <i>W</i>1–<i>W</i>4 a useful indicator for quantifying <i>f</i>_esc(LyC) and <i>f</i>_esc(Ly_α) in addition to the previously established some characteristics of LyC galaxies in the optical and ultraviolet ranges. Thus, the radiation of galaxies in the midinfrared range can be used to search for candidates for leaking LyC galaxies with the purpose of their further observations.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 2","pages":"90 - 97"},"PeriodicalIF":0.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5295977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radio Properties of the Low-Redshift Isolated Galaxies with Active Nuclei","authors":"N. G. Pulatova,&nbsp;I. B. Vavilova,&nbsp;A. A. Vasylenko,&nbsp;O. M. Ulyanov","doi":"10.3103/S088459132302006X","DOIUrl":"10.3103/S088459132302006X","url":null,"abstract":"<p>The properties of 61 isolated galaxies with active nuclei (isolated AGNs) in the radio frequency range at redshifts <i>z</i> &lt; 0.05 have been studied. The sample is obtained by cross-matching of the 2MIG catalog (2MASS catalog of isolated galaxies based on the 2MASS) with the Véron-Cetty catalog of quasars/AGNs. The sample is limited to a stellar magnitude of 4^<i>m</i> &lt; <i>K</i>_s ≤ 12^<i>m</i>, a radial velocity of <i>V</i>_<i>r</i> &lt; 15 000 km/s, and the distance to the nearest large satellite galaxy. These limitations indicate that the isolated AGNs have not collided with other galaxies in at least 3 billion years, and the observed activity of their nuclei is due only to physical processes occurring in the torus–accretion disk–nuclear region–supermassive black hole system. This study systematized the radio parameters of isolated AGNs by using data from various databases and the archive of terrestrial and space telescopes. Such characteristics are necessary for the further comparative study of physical properties of regions with active star formation and the active nuclei of these galaxies with the properties that manifest themselves when observing other spectral ranges. As a result, the radio flux densities available from the databases at a frequency of 1.4 or 5 GHz for isolated AGNs from the 2MIG catalog are given. Among the 61 galaxies of the sample, flux densities at 1.4 GHz have been found for 51 galaxies. These values are in the range of 3–20 mJy for most isolated AGNs and in the range of 50–200 mJy for two galaxies PGC35009 and NGC6951, while two galaxies ESO483-009 and ESO097-013 have spectral flux densities of 352 and 1200 mJy, respectively. The flux densities of ten isolated AGNs are less than 3 mJy. Radio flux densities of NGC0157 are not related to the position of this galaxy. Ratio <i>R</i> of the spectral flux densities in the radio frequency range to those in the optical bands have been calculated. Since the flux densities at 5 GHz are measured only for eight isolated AGNs, the required values of spectral flux densities at 5 GHz on the basis of relationship <i>S</i>_ν ∝ ν^–α for galaxies of the Seyfert type have been calculated by using the radio flux density values at 1.4 GHz and assuming that the spectral index is equal to α = 0.7. The radio fluxes densities at 5 GHz are lower than 3 mJy for 27 isolated AGNs, are in the range of 4–15 mJy for 15 AGNs, and in the range of 15–55 mJy for seven AGNs, while two galaxies ESO097-013 and ESO483-009 have radio fluxes densities of 304 and 132 mJy, respectively. We have found that 51 isolated AGNs are radio quiet sources (<i>R</i> &lt; 10), the radio properties of nine objects are absent, and ESO483-009 is a radio loud galaxy (<i>R</i> = 20.72, Sy3/LINER, and SAB00 pec). We propose the observational methods to determine the flux densities of radio quite isolated AGNs. In conclusion, the systematization of the propert","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 2","pages":"98 - 115"},"PeriodicalIF":0.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4942620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ionospheric Effects of the Kamchatka Meteoroid: Results of GPS Observations","authors":"Y. Luo,&nbsp;L. F. Chernogor","doi":"10.3103/S0884591323020058","DOIUrl":"10.3103/S0884591323020058","url":null,"abstract":"<p>The most important event in astronomy and celestial physics in the early 21st century is the fall of the Chelyabinsk meteoroid with a kinetic energy of nearly 440 kt TNT. Such an event occurs once every 65 years on average. The effects of this celestial body are considered in more than 200 scientific papers. At the same time, less than 25 papers are devoted to the fall of another large meteoroid called the Kamchatka meteoroid on December 18, 2018, at 23:48:20 UT (Universal time). Meanwhile, the parameters of this meteoroid are quite unique. The velocity components are <i>v</i>_<i>x</i> = 6.3, <i>v</i>_<i>y</i> = –3, and <i>v</i>_<i>z</i> = –31.2 km/s, and the velocity magnitude was 32 km/s. The total optical radiated energy was <i>E</i>_r = 1.3 × 10¹⁴ J (31 kt of TNT), the fireball explosion altitude was <i>z</i>_<i>r</i> = 26 km, and the coordinates are 56.9° N, 172.4° E. The angle of entry into the atmosphere with respect to the horizon was close to 68.6°. The meteoroid had the initial kinetic energy of 173 kt of TNT, the mass of 1.41 kt, and the size of nearly 9.4 m. The fall of such bodies occurs at a frequency of once every 30 years. It is of interest to perform the further study of its ionospheric effects and compare the results measured by ground-based and satellite methods with each other. The objective of this study is to analyze the results of GPS observations for the ionospheric effects to compare them with the results measured by the method of ground-based oblique incidence sounding of the ionosphere. To observe the ionospheric disturbances following the fall of the Kamchatka meteoroid, an AC60 receiving station (geographic coordinates, 53° N, 173° E) located at a distance of 450 km from the Kamchatka meteoroid explosion site and six GPS satellites (PRN02, PRN05, PRN07, PRN09, PRN29, and PRN30) were used. The principal results of these studies are the following. GPS technologies were used to estimate the delay times of ionospheric response to the Kamchatka meteoroid explosion, the horizontal propagation velocities of disturbances (504–520 m/s) and their periods (11–18 min), durations (22–35 min), wavelengths (333–530 km), and the relative amplitudes of electron density disturbances (3–4%). The estimate obtained for the relative amplitudes of wave disturbances in the electron density by the ground-based and satellite methods have proven to be close to each other (3–4%). Their periods also have close values (10–15 min). The ground-based and satellite methods also revealed the wave disturbances associated with both atmospheric gravity and seismic waves.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 2","pages":"71 - 77"},"PeriodicalIF":0.5,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4942627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiometric On-Orbit Calibration of the Aerosol-UA Mission Scanning Polarimeter: Technique, Design Elements, and Illumination Angles","authors":"I. I. Syniavskyi,&nbsp;V. O. Danylevsky,&nbsp;Y. A. Oberemok,&nbsp;Y. S. Ivanov,&nbsp;R. S. Osypenko,&nbsp;M. G. Sosonkin,&nbsp;G. P. Milinevsky,&nbsp;I. V. Fesianov","doi":"10.3103/S0884591323010075","DOIUrl":"10.3103/S0884591323010075","url":null,"abstract":"<p>The concept of a device for the radiometric calibration of photometers or polarimeters on the Earth orbit using the Sun is considered. The shortcomings and advantages for the designing and materials of the key elements are analyzed. The illumination conditions are determined for the working element of the radiometric calibration assembly of the ScanPol scanning polarimeter aboard the YuzhSat satellite platform for different configurations in different orbit locations. The satellite orbit sections where solar illumination is optimal for the working element of this assembly from the viewpoint of the relation between the incidence and observation angles and minimization of the light caused by reflection from the Earth surface, atmosphere, ScanPol structure elements, and satellite platform are specified. The obtained results are planned for use in the development of an optimal design for the ScanPol radiometric calibration assembly to provide a necessary radiometric measurements precision during the Aerosol-UA space mission.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 1","pages":"49 - 69"},"PeriodicalIF":0.5,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4799614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compact Galaxies with Active Star Formation from the SDSS Data Release 16: Star-Formation Rates Based on the Luminosities of Forbidden Emission Lines in the Optical Range","authors":"I. Y. Izotova,&nbsp;Y. I. Izotov","doi":"10.3103/S0884591323010038","DOIUrl":"10.3103/S0884591323010038","url":null,"abstract":"<p>We obtained equations for determining the star-formation rate in local compact star-forming galaxies from the SDSS Data Release 16 using luminosities of the forbidden emission lines [O II] λ 372.7 nm, [Ne III] λ 386.8 nm, [O III] λ 495.9 nm, and [O III] λ 500.7 nm and their combinations. The equations are based on the assumption that the star-formation rates, determined from the luminosity of the forbidden lines and H_β emission lines, are equal. This approach is especially useful because the observation of H_β emission is not always possible. For example, in galaxies with redshift <i>z</i> &gt; 1, this line goes beyond the optical range, and the [O II] λ 372.7 nm line, the [Ne III] λ 386.8 nm line, or their combination can be used instead. On the other hand, in many studies of faint objects using low-resolution spectra, the H_β line merges with the stronger [O III] λ 495.9 nm and [O III] λ 500.7 nm lines. In these cases, [O III] lines and their combination can be used to determine the rate of star formation. The resulting equations can be applied to compact star-forming galaxies in a wide range of redshifts.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 1","pages":"24 - 32"},"PeriodicalIF":0.5,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4797877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical Analysis of the Probability of Interaction of Globular Clusters with Each Other and with the Galactic Center on the Cosmological Time Scale According to Gaia DR2 Data","authors":"M. Ishchenko,&nbsp;M. Sobolenko,&nbsp;P. Berczik,&nbsp;T. Panamarev","doi":"10.3103/S0884591323010026","DOIUrl":"10.3103/S0884591323010026","url":null,"abstract":"<p>This study is aimed at investigating the dynamic evolution of the orbits of stellar globular clusters (SGCs). To integrate the orbits backward in time, the authors use models of the time-varying potentials derived from cosmological simulations, which are closest to the potential of the Galaxy. This allows for estimating the probability of close passages (“collisions” herein) of SGCs with respect to each other and the Galactic center (GC) in the Galaxy undergoing dynamic changes in the past. To reproduce the dynamics of the Galaxy in time, five of the 54 potentials previously selected from the IllustrisTNG-100 large-scale cosmological database, which are similar in their characteristics (masses and dimensions of the disk and halo) to the current physical parameters of the Milky Way, are used. With these time-varying potentials, we have reproduced the orbital trajectories of 143 SGCs 10 billion years back in time using our original φ-GPU high-order N-body parallel dynamic computer code. Each SGC was treated as a single physical particle with the assigned position and velocity of the cluster center from the Gaia DR2 observations. For each of the potentials, 1000 initial conditions were generated with randomized initial velocities of SGCs within the errors of the observational data. In this study, we consider close passages to be passages with a relative distance of less than 100 pc and a relative speed of less than 250 km s^–1. Clusters that pass at longer distances and/or with higher velocities do not have a substantial dynamic effect on the orbits of SGC. In our opinion, the largest changes in the orbits of clusters can be caused by clusters that pass with low velocities at distances smaller than several fold (for example, fourfold) the sum of the radii of the cluster half-masses. Therefore, the authors regard such close passages separately (for brevity, we will call such passages “collisions”). To select clusters that pass at close distances from the GC, the following criterion is applied based only on the relative distance: it must be less than 100 pc. Applying the above criteria, the authors obtained statistically significant rates of close passages of SGCs with respect to each other and to the GC. It has been determined that SGCs during their evolution have approximately ten intersecting trajectories with each other on the average and approximately three to four close passages near the GC in 1 billion years at a distance of 50 pc for each of the chosen potentials.</p>","PeriodicalId":681,"journal":{"name":"Kinematics and Physics of Celestial Bodies","volume":"39 1","pages":"33 - 44"},"PeriodicalIF":0.5,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4797444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}