The discovery of very slow pulsations ( P _ { spin } = 5560 s ) has solved the long-standing question of the nature of the compact object in the high-mass X-ray binary 4U 2206+54 but has posed new ones .
According to spin evolutionary models in close binary systems , such slow pulsations require a neutron star magnetic field strength larger that the quantum critical value of 4.4 \times 10 ^ { 13 } G , suggesting the presence of a magnetar .
We present the first XMM-Newton observations of 4U 2206+54 and investigate its spin evolution .
We find that the observed spin-down rate agrees with the magnetar scenario .
We analyse ISGRI/ INTEGRAL observations of 4U 2206+54Â to search for the previously suggested cyclotron resonance scattering feature at \sim 30 keV .
We do not find a clear indication of the presence of the line , although certain spectra display shallow dips , not always at 30 keV .
The association of these dips with a cyclotron line is very dubious because of its apparent transient nature .
We also investigate the energy spectrum of 4U 2206+54 in the energy range 0.3-10 keV with unprecedented detail and report for the first time the detection of very weak 6.5 keV fluorescence iron lines .
The photoelectric absorption is consistent with the interstellar value , indicating very small amount of local matter , which would explain the weakness of the florescence lines .
The lack of matter locally to the source may be the consequence of the relatively large orbital separation of the two components of the binary .
The wind would be too tenuous in the vicinity of the neutron star .