Cosmic-ray, neutrino, and gamma-ray observations combined with traditional electromagnetic wave observations provide a unique and powerful tool to explore how particles get accelerated and propagated in our Universe. This overview presentation will highlight recent results and future expectations using these multi-messenger observations to study extreme environments throughout the cosmos.
We construct non-thermal emission theory, interpreting the observational properties of a newly discovered pulsar 2XMM J104608.7-594306 in X-rays that is believed to be thermally emitting isolated neutron star. A different approach of curvature emission scenario is considered, giving the spectral energy distribution that is in a good agreement with the XMM-Newton observational data, which can...
Cygnus A is a giant elliptical galaxy, one of the most powerful radio galaxy. Like other radio galaxies, its activity is determined by active galactic nucleus (AGN) - supermassive black hole, surrounded by accretion disk, and with two relativistic jets, diverging in opposite directions from the supermassive black hole. We investigate the two hotspots - A and B - at the end of the eastern...
Gamma-ray bursts are thought to be accelerators of cosmic rays and a source of high-energy astrophysical neutrinos. Nevertheless, none of previous GRBs researches have shown a correlation between particular events and high-energy neutrinos. In the light of the first detection of TeV gamma-ray emission from GRB190114C, our goal is to explore the possibility of detecting the neutrino fluxes...
Galaxy clusters (GCs) are the largest and most massive gravitationally bound objects in the large-scale
structure of the Universe. Due to keV temperatures of virialized gas in the intracluster medium (ICM) and presence of cosmic rays (CRs), GCs are effective sources of thermal X-ray radiation and non-thermal leptonic (synchrotron) radio emission. GCs are also store-rooms for hadronic CRs, but...
IGR J15038–6021 is a Galactic X-ray source known to have an iron emission line and a hard X-ray spectrum. Here, we report on X-ray observations of the source withXMM-Newton and NuSTAR. Timing analysis of the XMM data shows a significant detection of 1646s period. The signal has a pulsed fraction of 22 in the 0.3–12 keV range. The X-ray spectrum is consistent with the continuum emission...
A connection between Supermassive Black Holes (SMBH) and galaxy growth has been suggested by a number of studies, based on empirical correlations between BH mass and integrated galaxy properties as galaxy bulge mass, total stellar mass, velocity dispersion and star formation rate (SFR). In particular current studies show that SFR and AGN activity appear to follow similar patterns with cosmic...
We present the results of photometric observations and research of blazar PKS1222+216 with high temporal resolution (30–60 s) in the B, V and R filters of Johnson/Bessel system. The observations were performed with the AZT-8 (D = 0,7 m; F = 2.8 m; CCD PL4710-1-BB-E2V) telescope of the observation station Lisnyky of Astronomical Observatory of Taras Shevchenko National University of Kyiv during...
Blazar variability appears to be stochastic in nature. However, a possibility of low-dimensional chaos was considered in the past, but with no unambiguous detection so far. If present, it would constrain the emission mechanism by suggesting an underlying dynamical system. We rigorously searched for signatures of chaos in \textit{Fermi}-Large Area Telescope light curves of 11 blazars. The data...
Hereby we present the results of photometric observations and research of two BL Lacertae objects: Markarian 501 and Markarian 421. The observations were performed with the AZT-8 (D = 70 cm, F = 2.8 m) telescope of the observation station Lisnyky of Astronomical Observatory of Taras Shevchenko National University of Kyiv during 2018-2020. The AZT-8 equipped with the PL4710-1-BB-E2V CCD and...
Thanks to the last years great success of the European Space Agency space mission GAIA and the latest data release of the 3D stellar positions and velocities in our Galaxy we now have a very accurate and homogenous data for the Milky Way Globular Cluster (GC) system space positions and velocities up to 200 kpc of Galactocentric distances. Based of the GC system current coordinates and...
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We use different machine learning techniques to create and compare classifiers for the search of compact star-forming galaxies (CSFGs). The methods considered were: k-nearest neighbours, deep neural network, and gradient...
We consider a data driven approach as an alternative to the traditional photometric techniques to determine distance moduli m-M to the galaxies. In our first work (Elyiv et al., 2020, Astron. & Astrophys.) we tested the five machine learning regression techniques for inference of
The 4XMM-DR10 catalogue is the largest database of X-ray sources, the last version of which contains 575158 unique X-ray. The aim of our work was to obtain a sample of X-ray galaxies. To reach this goal, we created the sample based on the HyperLEDA database that consists of 7181 objects. In the current work, we present general properties of the sample, namely the distribution in equatorial...
We calculated morphological parameters for test sample of 4659 galaxies from VIPERS survey. These parameters includes Gini, M20, Concentration, Asymmetry and Smoothness. Results correlate with the distribution of these parameters for other simulated and observed samples. We also studied dependence of these parameters with Sersic power index of radial distribution of surface brightness of galaxy image.
Black holes are one of the most mysterious objects in the universe. These objects(as you know) attracts particles towards it. It’s is formed when a heavy star dies,it forms a 4d curve in the space-time and attracts everything towards it. With this curvature,time is also effected. The more we go closer to the black hole the more the time gets dilated. This is explained by Einstein’s famous twin...
Galaxies interact with each other forming bigger galaxies, following the hierarchical scenario, where bigger structures evolve from smaller ones. Here, I will explore how signatures of hierarchical evolution can be found in the distribution of light, kinematics and dynamics of nearby galaxies while in the meantime understand the difficulties on the carried out research that is done in this field.
Investigating period changes of classical Cepheids through the framework of
Galaxies evolve embedded in a vast gaseous halo that dwarfs the mass and spatial extent of stars in the galactic disk. Photoionization modeling suggests that cold circumgalactic gas has significantly lower densities than expected by theoretical predictions based on thermal pressure equilibrium with hot CGM gas. In this talk, I will demonstrate the impact of cosmic ray physics on the formation...
We present a a detailed study of the Double Periodic Variable V4142 Sgr based on photometric and spectroscopic analysis. We re-analized and improved an orbital period of
FUors are young stellar objects characterized by a sudden increase in accretion rate, followed by a slower decline in brightness. Eruptive young stars can sometimes be accompanied by bipolar molecular outflows which can significantly alter the system's environment. Additionally, these energetic processes might represent an important factor in clearing out the environment of the protostar, thus...
Barium stars (Ba stars) have got special spectrum enriched in the elements of the slow neutron-capture process (s-process), created in asymptotic giant branch (AGB) stars. However, these stars have not reached the AGB phase yet, thus they preserve accreted material from an already evolved companion.
In this work, we have studied the elemental abundances of 55 Ba stars, comparing their...
Polarization is an important property of light. It has been regularly detected in scattered light and it could be emitted from the sources with a strong magnetic field (e.g. magnetic cataclysmic binary systems, neutron stars, etc.) and its properties are linked to the internal geometry of a source of radiation and scattering environment. As a consequence, polarimetry complements photometric...
Circumgalactic medium (CGM) has many similarities with interstellar and intergalactic medium yet there are still many questions regarding its nature, inner motion, and interaction with other media. This work is summarizing the general theoretical background of CGM, listing currently available research methods, including computer modeling, and giving a kick-start for future analysis. The main...
In this work we present optical, X-ray, UV photometry, X-ray spectroscopy of dwarf nova Gaia18awg (ASASSN-16le).We report an analysis of photometry, spectroscopy and measurements of physical, orbital characteristics. Gaia18awg is a U Gem + SU Uma dwarf nova system. That system showing non-periodic outbursts and super-outbursts, superhumps during superoutbursts. From Lisnyky (MPC 585) data we...
Stellar flares are the most easily observable manifestations of magnetic activity. With the advent of high precision spaceborn photometry, our knowledge on flares increased significantly. While most of the studies so far focused on simple observables like flare energy or amplitude, here we aim to use all the morphological information encoded in the flare light curves. Using data from the...
Investigating period changes of classical Cepheids through the framework of
The Kepler space telescope observed multiple globular clusters during the K2 mission. These high-quality and continuous measurements constitute a unique opportunity to investigate RR Lyrae stars found in these old clusters. NGC5897 was observed by Kepler in Campaign 15. First, we used Gaia DR2 data to obtain the color-magnitude diagram of the globular cluster. We verified the known RR Lyrae...
Variable stars are stars of variable brightness. This means that their brightness doesn’t remain constant throughout time. Eclipsing variables are binary stars where two stars orbit periodically around their common center of mass. When one of them is situated in front of the other relative to the observer, the total brightness of the system decreases. These brightness variations depend only on...
The main obstacles for low-frequency radio spectroscopy of the interstellar medium lie in the low intensities of studied features and high level of terrestrial interferences. Growing interest to carbon radio recombination lines (RRLs) studies at decametric wavelengths encourage world radio astronomers to search for new methods and hardware which are able to overcome the existing difficulties....
Parker Solar Probe (Fox et al., 2016) is the first spacecraft to go close enough to the Sun to sample the in-situ characteristics of the young solar wind during its formation aiming to trace the flow of energy that heats and accelerates the solar corona and solar wind; to determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and to explore...
The problem of the penetration of electric fields from atmospheric near-Earth ULF electric current sources to the ionosphere is investigated both within the dynamic simulations of the Maxwell equations in the frequency domain and within the simplified quasi-stationary approach.
Two cases of the geomagnetic filed lines are considered. The first case is the penetration of the geomagnetic filed...
Turbulent wave fluctuations of plasma parameters obtained from the spacecraft measurements have mixed manifestations of spatial and temporal scales due to the dynamics of the considered environment. Decomposing of such plasma perturbations into frequency and spatial range have allowed us to analyse power distribution in branches of dispersion equations. We have demonstrated efficiency of each...
We represent the method of modelling of the HII regions surrounding continuous star-forming regions. The complex "bubble-like" structure of the HII region has been divided into internal and external components. Internal components correspond to the region of free expansion of superwind and the cavity of superwind correspondinly, while the external ones - to a layer of gas, compressed by a...
The last decade has become a significant time for robotic exploration bodies of the solar system. Among such research programmes was The Dawn Mission to asteroid Vesta and dwarf planet Ceres, whose results allow us to carry out a detailed analysis of asteroid (4) Vesta surface properties by using methods that were developed and effectively used in the analysis of the Moon data.
Images of...
Since NASA is planning Lucy Mission to Trojan asteroids, comparative ground and space photometry are very important for calibrating further ground-based photometric observations. The asteroid Trojan Hektor (624) was observed at the Lisnyky astronomical station (MPC 585). For observations we used the 0.7 m (f/4) reflector AZT-8 with FLI PL4710 CCD camera and filter R of Johnson – Cousins...
Using the software Astrometrica and Maxlm DL5 to the observed data for two distant comets C / 2014 B1 (Schwartz) and C / 2012 K6 (McNaught) obtained on the 2nd telescope at Terskol, their values of apparent magnitude were obtained. Using the value of the visible stellar magnitude, the absolute stellar magnitude, dust productivity in the form of the parameter Afρ were calculated, and the...
In this work, the results and analysis of my observations of the Perseid meteor shower at the maximum of its activity on 12-13 August in 2017 - 2020 are presented. They were the one-sided visual observations, that were carried out in Kyiv by the astronomical group of gymnasium № 59. Observations and processing of data observations were carried out using the methodology of the International...
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Active asteroids are relatively new objects to study in the Solar system; they have asteroid-like orbits but exhibit comet-like activity. The study of active asteroids allows one to cross the traditionally drawn lines...
Based on observations of the comet C/2020 F3 (NEOWISE) from July 23 to August 11, 2020, the dust tail of the comet was studied at the Gissar Astronomical Observatory of the Institute of Astrophysics of the NAST. The cometocentric coordinates of the comet's tail were determined by Moiseev's method and the effective acceleration of dust particles of the comet's tail was calculated. The results...
The report considers the analysis of the correlation coefficient of photometric parameters of selected short-period Jupiter family comets on the Wolf number and the area of sunspots. It is shown that the correlation coefficient of photometric parameters of some comets is not very strongly related to the activity of the Sun.
We represent the method of modelling of the HII regions surrounding continuous star-forming regions. The complex "bubble-like" structure of the HII region has been divided into internal and external components. Internal components correspond to the region of free expansion of superwind and the cavity of superwind correspondinly, while the external ones - to a layer of gas, compressed by a...
