K. Pottschmidt, S. Suchy, E. Rivers, R. E. Rothschild, D. M. Marcu, L. Barragán, M. Kühnel, F. Fürst, F. Schwarm, I. Kreykenbohm, J. Wilms, G. Schönherr, I. Caballero, A. Camero-Arranz, A. Bodaghee, V. Doroshenko, D. Klochkov, A. Santangelo, R. Staubert, P. Kretschmar, C. Wilson-Hodge, M. H. Finger, Y. Terada
Seventeen accreting neutron star pulsars, mostly high mass X-ray binaries
with half of them Be-type transients, are known to exhibit Cyclotron Resonance
Scattering Features (CRSFs) in their X-ray spectra, with characteristic line
energies from 10 to 60 keV. To date about two thirds of them, plus a few
similar systems without known CRSFs, have been observed with Suzaku. We present
an overview of results from these observations, including the discovery of a
CRSF in the transient 1A 1118-61 and pulse phase resolved spectroscopy of GX
301-2. These observations allow for the determination of cyclotron line
parameters to an unprecedented degree of accuracy within a moderate amount of
observing time. This is important since these parameters vary - e.g., with
orbital phase, pulse phase, or luminosity - depending on the geometry of the
magnetic field of the pulsar and the properties of the accretion column at the
magnetic poles. We briefly introduce a spectral model for CRSFs that is
currently being developed and that for the first time is based on these
physical properties. In addition to cyclotron line measurements, selected
highlights from the Suzaku analyses include dip and flare studies, e.g., of 4U
1907+09 and Vela X-1, which show clumpy wind effects (like partial absorption
and/or a decrease in the mass accretion rate supplied by the wind) and may also
display magnetospheric gating effects.
View original:
http://arxiv.org/abs/1111.1800
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