A Close Look On GX 301-2 With Suzaku And XMM-Newton
Abstract
We present an in-depth study of the accreting pulsar and HMXB GX 301-2 using data from Suzaku and XMM-Newton for different parts of the 41.5d orbit. The overall spectrum is well fitted with a cutoff-powerlaw continuum modulated by a partial covering model at low energies. The absorption column is strongly variable between 12-24e23 atoms/cm² on time scales as short as a few 100sec, as well as strongly depending on orbital phase.
Different fluorescent lines are found in the spectrum, the most prominent being the iron K-alpha line, which is responsible for 12% of the 2-10keV flux. Besides this line, an iron K-beta line and the K-alpha lines of sulfur, argon, calcium, and nickel are evident. Strong indications exits also that a chromium K-alpha and a nickel K-beta line is visible during the pre-periastron flare XMM data. Using the strong fluorescent lines we draw conclusions on the ionization state of the plasma and the abundance of the host elements. A cyclotron resonant scattering feature is visible at 35-40 keV, varying with flux and pulse phase. Spectral continuum parameters are also variable over the two-peaked pulse profile, e.g., the photon index is clearly softer during the secondary peak. We present possible accretion geometries and discuss the size and geometry of the absorbing medium based on these results. This work was founded by DLR, DAAD, the European Commission, and NASA.- Publication:
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AAS/High Energy Astrophysics Division #12
- Pub Date:
- September 2011
- Bibcode:
- 2011HEAD...12.4202F