The five low-energy constants (LECs) in the electromagnetic current derived
in chiral effective field theory (χEFT) up to one loop are determined by a
simultaneous fit to the A=2--3 nuclei magnetic moments and to the
deuteron magnetic form factor and threshold electrodisintegration at backward
angles over a wide range of momentum transfers. The resulting parametrization
then yields predictions for the 3He/3H magnetic form factors in excellent
accord with the experimental values for momentum transfers ranging up to
≈0.8 GeV/c, beyond the expected regime of validity of the χEFT
approach. The calculations are based on last-generation two-nucleon
interactions including high orders in the chiral expansion and derived by
Entem, Macheleidt, and Nosyk [Phys.\ Rev.\ C {\bf 96}, 024004 (2017)] and by
Piarulli {\it et al.} [Phys.\ Rev.\ C {\bf 94}, 054007 (2016)], using different
χEFT formulations. In the A=3 calculations, (chiral) three-nucleon
interactions are also accounted for. The model dependence resulting from these
different formulations of the interactions is found to be mild for momentum
transfer below ≈0.8 GeV/c. An analysis of the convergence of the chiral
expansion is also provided.Comment: 12 pages, 8 figure