Extended Data Fig. 4: X-ray luminosity and spectral properties of magnetars15 compared with the X-ray luminosity limits of GLEAM-X J162759.5-523504.3.
From: A radio transient with unusually slow periodic emission
The two faintest known magnetars are labelled. The coloured contours represent expected Swift XRT count rates for putative X-ray luminosities and blackbody temperatures for a source at 1.3 kpc, assuming a hydrogen column density of NH ≈ 2 × 1021 cm−2. The grey dashed line represents the implied luminosity upper limit for GLEAM-X J162759.5-523504.3 based on the 3 − σ upper limit obtained from the Swift XRT observation. From the magnetar fundamental plane, we predict GLEAM-X J162759.5-523504.3 to have a quiescent luminosity 4.5 orders of magnitude lower than our limit from the Swift XRT.
