Giant Flare Energy Budgets: The Three Recorded Events Against the Magnetic Reservoir of Their Host Stars

Three times in the modern era of X-ray astronomy a neutron star has released, in less than a second of peak emission, more energy than the Sun radiates in a quarter of a million years. The events of March 1979, August 1998 and December 2004 define the upper end of magnetar energetics, and any account of where that energy is stored must survive comparison with all three. Working from published values for the sources concerned, this paper computes the relevant quantities under one stated set of conventions and compares them source by source. Headline results: largest flare source SGR 1806-20; largest flare energy erg 2.0e+46; largest flare fraction of reservoir 0.032; smallest flare fraction of reservoir 2.45e-03; reservoir SGR1806 erg 6.31e+47. The comparisons are budget statements: they establish whether the energies, stresses, powers and timescales involved are mutually consistent, and by what margin. Every number quoted is produced by the deposited compute.py script from the stated inputs, and the full per-source record is deposited as results.json alongside the text.