Anton Gluchshenko

This paper presents the architecture of the Kazakhstani National Virtual Observatory (KazVO)—an International Virtual Observatory Alliance (IVOA) compliant node that unifies the heterogeneous observational datasets of the Fesenkov Astrophysical Institute (FAI). The architectural foundation of the system is built upon a partitioned Data Lake, a German Astrophysical Virtual Observatory (GAVO) Data Center Helper Suite (DaCHS) publishing backend, and a PostgreSQL database in which metadata for published observational products are mapped to IVOA ObsCore, while catalogs and simulation grids use dedicated relational tables. We follow Open Science principles by introducing a metadata-only showcase model based on a four-class data embargo mechanism. Machine-to-Machine services deployed via IVOA protocols are exposed through the KazVO publishing registry registered in the global Registry of Registries (RofR), enabling analysis of Kazakhstani observational assets within external clients such as Tool for OPerations on Catalogues And Tables (TOPCAT), Aladin, and PyVO. The current implementation combines operational VO publication services and targeted photometric processing with scheduled, batch-mode data ingestion, supporting access to published historical and modern observational holdings. Replication has been validated on pilot datasets, while routine deployment at the observing sites and automated reduction of modern spectroscopic streams remain under development. The architecture provides a framework for progressively integrating these components into a complete data lifecycle.

This paper presents an automated pipeline for wavelength calibration of slit-based astronomical spectra, combining robust peak-matching techniques with a lightweight preprocessing step. The method is based on initial peak alignment using Dynamic Time Warping (DTW), followed by refinement of the dispersion solution with the Random Sample Consensus (RANSAC) algorithm. To ensure consistency between observed and reference spectra, a compact one-dimensional convolutional neural network (CNN) is employed at the preprocessing stage to identify the spectral range and corresponding diffraction grating. This step enables the selection of an appropriate reference spectrum but does not directly affect the calibration procedure. The DTW-based approach provides reliable initial correspondences between spectral peaks under nonlinear distortions and noise, while RANSAC filtering removes incorrect matches and yields a robust polynomial dispersion solution. The method is validated on real observational data from calibration lamps and demonstrates stable performance, high matching accuracy, and full automation capability. Compared to traditional manual or semi-automatic approaches, the proposed pipeline significantly reduces processing time while maintaining calibration precision. The developed solution is planned to be deployed as a service in the virtual observatory infrastructure and is applicable for processing numerous spectral data.

We establish the multimessenger mechanics of episodic mass transfer in supermassive black hole binaries stalled within circumbinary discs. Utilizing continuous wavelet transforms, we isolate localized gas clumps at the cavity edge and track their evolution. By regularizing the forced fluid equations at Lindblad resonances via the inhomogeneous Airy differential equation, we bypass linear Wentzel–Kramers–Brillouin singularities to extract the finite wave amplitudes that trigger nonlinear shock formation. These shocks produce bounded accretion bursts. We model the time-domain thermal luminosity, utilizing the Fourier shift theorem to derive an analytical power spectral density that forms an extended harmonic cascade. The superposition of the accretion streams generates a spectral beat frequency, providing a theoretical diagnostic template to estimate the binary mass ratio, though sensitive to intrinsic cavity shape. The radiative cooling of shock-accelerated electrons produces a multiwavelength spectral energy distribution from a synchrotron radio continuum to an inverse-Compton gamma-ray tail, regulated by pair-production thermostats. We identify a relativistic signature: a discontinuous, high-frequency gravitational wave sideband termed the “background gas humming.” We analytically differentiate this from steady spiral pattern speeds, showing it arises from the physical advection of highly localized, transient fluid hot spots following accretion shocks. Evaluating the asymptotic properties of the Airy regularization, we show that this humming manifests as a sequence of discrete high-frequency bursts with temporal quiescence gaps that systematically compress as the cavity shrinks. We show that the instantaneous accretion rate of the gas actively trapped within the cavity violently amplifies prior to decoupling, culminating in a terminal burst near 4 mHz (normalized to a 10 ⁶ M _⊙ system) that serves as a multimessenger precursor to the final vacuum inspiral.

We investigate the orbital eccentricity evolution of supermassive black hole binaries (SMBHBs; 10 ⁴ –10 ⁷ M _⊙ ) within galactic environments. Merger timescales depend on eccentricity when gravitational-wave (GW) emission dominates. We analyze the dynamics in triaxial merger remnants and subsequent interactions with geometrically thick nuclear disks. Gravitational torques in triaxial potentials extract angular momentum ( T _J ≪ T _E ), resulting in binary formation with high initial eccentricities ( e > 0.95). We analyze the binary–disk interaction using a 3D analytical framework incorporating the Airy formalism and present a self-consistent derivation demonstrating that the 3D suppression of high-order torques leads to distinct scalings with disk thickness ( h ), with migration rates τ a − 1 ∝ h − 3 and eccentricity damping rates τ e − 1 ∝ h − 5 , which establish a timescale hierarchy, τ _e / τ _a ∝ h ² . For typical parameters, eccentricity damping is significantly faster than orbital decay ( τ _e ≈ 0.04 τ _a ). We further develop a wavelet-based formalism to quantify the impact of disk inhomogeneities arising from accretion feedback and turbulence. We derive the stochastic torque variance in the wavelet domain and employ a Fokker–Planck analysis to determine the equilibrium eccentricity distribution. While stochastic fluctuations counteract deterministic damping, the strong damping imposed by the thick disk geometry ensures the equilibrium eccentricity remains small unless the fluctuations are highly nonlinear. Hence, highly eccentric born SMBHBs are rapidly circularized. This “circularization trap” forces binaries to approach the GW-dominated regime on nearly circular orbits, prolonging the total merger timescale. This introduces a cosmological delay (0.3–2.5 Gyr) governed by stellar relaxation.

We present a modification of the original GalIC code, which is designed to generate equilibrium initial conditions for numerical $N$-body models of collisionless, gravitationally bound systems. The proposed approach focuses on improving the procedure for assigning initial particle velocities, which is crucial for ensuring the stability and physical consistency of equilibrium models. Instead of drawing trial velocities from a uniform distribution bounded by the local escape velocity, we introduce a Gaussian-like distribution with compact support. Its dispersion is adapted to the local properties of the system and is derived from the Jeans equations. This choice provides a more physically motivated sampling of velocity space while preserving the bound nature of the system. A detailed comparison with the original GalIC method is performed using isotropic Hernquist models. We demonstrate that the modified algorithm converges significantly faster and produces well-resolved time-averaged mass profiles and velocity distributions. The resulting models show improved convergence toward the target distribution function while maintaining a comparable computational cost per iteration. Overall, the proposed modification provides a more efficient and physically realistic framework for generating equilibrium $N$-body initial conditions in collisionless stellar dynamical systems.

Context. Based on the Gaia DR3, we reconstructed the orbital evolution of the known Milky Way globular clusters and found that six objects, NGC 6681, NGC 6981, Palomar 6, NGC 6642, HP 1, and NGC 1904, very likely interact closely with the nuclear star cluster. Aims. We study the dynamical evolution of selected Milky Way globular clusters and their interactions with the Galactic centre over cosmological timescales. We examine the global dynamical mass loss of these globular cluster systems, their close interactions with the Galactic centre, and the potential capture of stars by the Milky Way nuclear star cluster. Methods. For the dynamical modelling of the clusters, we used the parallel N-body code φ-GPU, which allows star-by-star simulations of the systems. Our current code also enabled us to follow the stellar evolution of individual particles, including the formation of high-mass remnants. The modelling was carried out in a Milky Way-like, time-variable potential (with a dynamically changing mass and scale length), obtained from the IllustrisTNG-100 database, with a full integration time of eight billion years. Results. Based on extensive numerical modelling and analysis, we estimated the mass loss and the global and inner structures of the selected six clusters. Over an evolution of eight billion years, the clusters lost ≈80% of their initial mass. We analysed the phase-space evolution of the individual unbound stars NGC 6681, NGC 6642, HP 1, and NGC 1904. We found that only NGC 6642 could potentially have been a source for populating the Milky Way nuclear star cluster in the past.