https://www.sjunijournals.ge/index.php/AA/issue/feedAstronomy & Astrophysics (CAUCASUS)2026-09-24T10:14:43+00:00Open Journal Systems<p>The journal “<strong>Astronomy & Astrophysics (Caucasus)</strong>” is an international, scientific peer-reviewed electronic publication. The purpose of the journal is to provide the scientific society with the information about the latest researches in astronomy and astrophysics. The technical parameters of the articles submitted to the “<strong>Astronomy & Astrophysics (Caucasus)</strong>” are similar to those of the articles published in the US leading international scientific journals. Only the original astronomical and astrophysical articles after with a positive review will be published in the journal.</p> <p>The journal also publishes papers of international scientific conferences (forums, symposiums, etc.), reports of scientific expeditions and reviews.</p>https://www.sjunijournals.ge/index.php/AA/article/view/419Macroscopic Quantum Horizon Interference and Gravitational-Wave Echo Signatures in GW1509142026-09-24T09:35:54+00:00Tushar Sentushar.sen@gmail.com<p>We present a self-consistent semiclassical framework demonstrating that macroscopic quantum horizon interference during binary black hole coalescence produces distinct gravitational-wave echoes. Modeling the horizon boundary as a non-lossless effective quantum impedance (Z<sup>Q</sup><sub>ℓm</sub> ∈ R), we derive a scale-free geometric localization radius σ = √ℓ<sub>P</sub>R<sub>s</sub>, which dictates a deterministic, mass-dependent echo time delay scaling as Δt<sub>echo</sub> ∝ M ln M.</p> <p>We validate this framework against open-source strain data for the landmark event GW150914 using numerical-relativity calibrated SEOBNRv4_ROM templates. Our pipeline extracts an unambiguous, highly significant matched-filter peak of ρ<sub>max</sub> =37.39 within the Hanford (H1) interferometer stream, demonstrating exceptional phase consistency with a secondary echo packet at exactly Δt<sub>echo</sub> = 0.29 seconds. While the Livingston (L1) tracking metrics are heavily modulated by local lowfrequency spectral power artifacts near the 20 Hz cutoff, the clean H1 signature provides compelling observational evidence for quantum sub-structures near black hole horizons. This framework offers an empirically falsifiable resolution to the black hole information paradox, establishing critical observational templates for next-generation space-based detectors such as LISA.</p>2026-09-24T00:00:00+00:00Copyright (c) 2026 24.09.2026https://www.sjunijournals.ge/index.php/AA/article/view/420Boundary-Driven Cosmic Expansion: A Purely Geometric Theory of Inflation2026-09-24T10:00:32+00:00Tushar Sentushar.sen@gmail.com<p>Cosmic inflation remains the leading paradigm for explaining the earliest stage of cosmological evolution, yet its underlying physical mechanism continues to motivate alternative theoretical descriptions. In this work, we introduce a purely geometric framework in which cosmic expansion emerges from the collective evolution of an infinite ensemble of independently expanding universes represented as three-dimensional spheres embedded in a common Euclidean space. Unlike conventional inflationary models, the proposed formulation introduces neither scalar fields, spacetime curvature, vacuum energy, nor modified gravitational dynamics. Instead, expansion is governed exclusively by the availability of unconstrained boundary. The central concept of the theory is the<br />free boundary fraction, a dimensionless geometric functional that measures the proportion of each universe’s boundary remaining free from overlap with neighbouring universes. Beginning from a small set of geometric axioms, we derive a closed boundary-driven dynamical system, establish the existence, boundedness, monotonicity, and limiting properties of the free boundary functional, and show that the resulting constitutive law naturally yields an initial phase of maximum boundary-driven expansion followed by a progressive, self-regulated reduction as collective boundary interactions accumulate. The resulting dynamics provide a mathematically self-contained geometric mechanism that qualitatively reproduces several characteristic features commonly associated with the inflationary epoch while remaining fundamentally distinct from conventional exponential inflation. Rather than attributing primordial expansion to additional physical fields or phenomenological potentials, the proposed framework demonstrates that collective boundary geometry alone is sufficient to generate heterogeneous expansion histories and intrinsic self-regulation. This work establishes a new geometric perspective on early-universe evolution and provides a mathematical foundation for future theoretical development, numerical simulation, and observational investigation.</p>2026-09-24T00:00:00+00:00Copyright (c) 2026 24.09.2026