Damghan University PressIranian Journal of Astronomy and Astrophysics2322-492413120260901Data-Driven Forecasting of Solar and Geomagnetic Activity Using Relative Sunspot Numbers114216410.22128/ijaa.2026.3417.1254ENSevim RanjbarFaculty of Physics, University of Tabriz, PO Box 51666-16471, Tabriz, IranSomayeh TaranFaculty of Physics, University of Tabriz, PO Box 51666-16471, Tabriz, Iran0000-0001-7101-7449Journal Article20260807Accurate modeling and forecasting of solar and geomagnetic activity is essential for advancing our fundamental understanding of solar-terrestrial interactions and magnetospheric dynamics. In this study, we propose a computational approach based on a Long Short-Term Memory (LSTM) neural network for predicting the 10.7 cm solar radio flux (\textnormal{F10.7}) and four widely used geomagnetic indices (\textit{K}\textsubscript{\textit{p}}, {\itshape Dst}, {\itshape ap}, and {\itshape AE}) using the Relative Sunspot Number (RSSN) as the primary input. To enhance the model's predictive capability, we introduce a physically motivated feature engineering strategy that incorporates nonlinear and temporal characteristics of solar dynamics, including quadratic and rolling-average features, as well as autoregressive information for each target variable. We employ a strictly leak-free Purged-Embargo validation strategy to prevent information leakage during model development. We evaluate the framework using hourly observations from 1 January 2000 to 10 January 2026, covering Solar Cycles 23, 24, and 25. Our proposed model achieves excellent predictive performance for the \textnormal{F10.7} and {\itshape Dst} indices, with coefficients of determination $R^2$ of 0.9639 and 0.9584, respectively. Good agreement is also obtained for the \textit{K}\textsubscript{\textit{p}} and {\itshape ap} indices ($R^2$ = 0.8642 and 0.8622), while the more dynamic {\itshape AE} index reaches an $R^2$ of 0.6939. These results demonstrate that the proposed framework provides an accurate and robust approach for forecasting solar and geomagnetic activity from a minimal set of input observations.https://ijaa.du.ac.ir/article_2164_9ee12ecf4ce0f630ce86c58b5863764a.pdfDamghan University PressIranian Journal of Astronomy and Astrophysics2322-492413120260901One- and Two-Dimensional Core-Collapse Supernova Simulations of a 15M$_{\odot}$ Progenitor Using Two-Moment Neutrino Transport and the Neutrino Leakage Scheme1546218310.22128/ijaa.2026.3405.1253ENKhodayar TaghiniyaramiDepartment of Theoretical Physics, Faculty of Basic Science, University of Mazandaran, P.O. Box 47416-95447, Babolsar, IranAlireza KhesaliFaculty of Physics, University of Tabriz, PO Box 51666-16471, Tabriz, IranAzar KhosraviDepartment of Geography, Faculty of Basic Sciences, Imam Ali Nazaja University, Postal Code: 1317893471, Tehran, IranJournal Article20260724We investigate the evolution of a $15\,M_{\odot}$ core-collapse supernova (CCSN) to examine the impact of dimensionality and the efficiency of the neutrino leakage approximation. First, a 1D reference simulation is performed using \texttt{Flash-X} coupled to the \texttt{thornado} two-moment transport module. We compare this reference shock evolution with a series of 1D \texttt{FLASH 4.6.2} leakage simulations calibrated with varying neutrino-heating factors ($f_{\mathrm{heat}}$). A calibrated factor of $f_{\mathrm{heat}}=1.60$ minimizes trajectory errors and reproduces the reference shock dynamics without triggering an artificial 1D explosion. This calibrated prescription is then applied to 2D \texttt{FLASH 4.6.2} simulations to study multidimensional shock dynamics at a reduced computational cost. In 2D, the model generates high-entropy buoyant plumes, increases the gain mass and advection timescale, and drives the ratio $\tau_{\mathrm{adv}}/\tau_{\mathrm{heat}}$ above unity. The absence of coherent growth in the lowest shock-deformation modes during the first $250\text{ ms}$ post-bounce indicates that shock revival is primarily driven by neutrino-driven convection rather than the standing accretion shock instability (SASI). Our results demonstrate that while the calibrated leakage scheme captures the early 1D post-bounce shock behavior, it successfully models the subsequent convection- and turbulence-driven shock expansion in 2D. This highlights that while neutrino heating provides the energy for the explosion, multidimensional convection governs how effectively this energy is retained and converted into sustained shock revival, where 1D model fails.https://ijaa.du.ac.ir/article_2183_b39b8297212d013646a82edbdb530936.pdf