Gravitational-Wave Strain from Magnetic Deformation of Magnetars: Ellipticity and Signal Budgets for the Known Population

A strong internal field deforms a neutron star, and a deformed star spinning about a misaligned axis radiates continuous gravitational waves. Magnetars carry the largest fields, hence potentially the largest deformations, but they also spin slowly, which suppresses the signal. Both effects enter the strain budget computed here for the known population. 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 h0 source SGR 1806-20; largest h0 3.3e-32; largest ellipticity 3.8e-06; smallest h0 9.5e-37. 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.