Physical Properties of the AXP 4U 0142+61 from X-ray Spectral Analysis

Understand

We analyze archival Chandra and XMM-Newton data of 4U 0142+61 within the context of the Surface Thermal Emission and Magnetospheric Scattering model.

• We show that 4U 0142+61 spectrum can be fit very well with this physical model that contains only four parameters.
• The system parameters can be tightly constrained from the fits, yielding a surface magnetic field strength of B=(4.75 \pm 0.02)x 10^{14} G, a surface temperature of kT = 0.309 \pm 0.001$ keV and a scattering optical depth of a few in the magnetosphere.
• These values do not vary between observations due to the stability of the source within the window of the observations.