e-CALLISTO FITS Analyzer: A Software Framework For CALLISTO Solar Radio Data

Abstract

Solar radio bursts are signatures of dynamic processes in the solar corona, including particle acceleration and shock propagation associated with solar flares and coronal mass ejections. The e-CALLISTO archive, the largest near-real-time solar radio network with 150+ stations, produces large FITS volumes affected by interference, noise, and irregular frequency setups. Each 15-minute CALLISTO frame can split a burst across files, complicating event-level analysis. This work presents the e-CALLISTO FITS Analyzer, a unified, interactive, cross-platform application for processing e-CALLISTO dynamic spectra on Windows, macOS, and Linux. The application merges fragmented observations across time and frequency, applies an RFI-mitigation/background-subtraction pipeline with user-controlled clipping, and isolates bursts using an interactive polygon mask. It extracts a maximum-intensity backbone, supports outlier removal, and fits a power-law model to estimate drift rates, with uncertainties from the fit and backbone scatter. Shock height and speed are calculated using the Newkirk coronal density model, with optional n-fold density scaling. If the harmonic emission lane is used instead of the fundamental lane, its frequency drift is fitted separately. Analytical checks and empirical comparisons show that converting the harmonic lane to fundamental frequency changes estimated shock height and speed by only a few percent. For a Type II burst at Arecibo Observatory on 2 March 2022, the analyzer yielded an average drift rate of −0.0400 ± 0.0003 MHz s−1 and an average shock speed of 449 ± 1 km s−1 at a height of 1.715 ± 0.002 R⊙. It supports reproducible, event-focused SRB analysis and improves access to physically meaningful, uncertainty-quantified measurements.