PSR B0943 + 10 is a mode-switching radio pulsar characterized by two emission modes with different radio and X-ray properties .
Previous studies , based on simple combinations of blackbody and power law models , showed that its X-ray flux can be decomposed in a pulsed thermal plus an unpulsed non-thermal components .
However , if PSR B0943 + 10 is a nearly aligned rotator seen pole-on , as suggested by the radio data , it is difficult to reproduce the high observed pulsed fraction unless magnetic beaming is included .
In this work we reanalyze all the available X-ray observations of PSR B0943 + 10 with simultaneous radio coverage , modeling its thermal emission with polar caps covered by a magnetized hydrogen atmosphere or with a condensed iron surface .
The condensed surface model provides good fits to the spectra of both pulsar modes , but , similarly to the blackbody , it can not reproduce the observed pulse profiles , unless an additional power law with an ad hoc modulation is added .
Instead , the pulse profiles and phase-resolved spectra are well described using the hydrogen atmosphere model to describe the polar cap emission , plus an unpulsed power law .
For the X-ray brighter state ( Q-mode ) we obtain a best fit with a temperature kT \sim 0.09 keV , an emitting radius R \sim 260 m , a magnetic field consistent with the value of the dipole field of 4 \times 10 ^ { 12 } G inferred from the timing parameters , and a small angle between the magnetic and spin axis , \xi = 5 ^ { \circ } .
The corresponding parameters for the X-ray fainter state ( B-mode ) are kT \sim 0.08 keV and R \sim 170 m .