2009A&A...508.1275B

We report on the first Suzaku observation of IGR J16318-4848, the most extreme example of a new group of highly absorbed X-ray binaries that have recently been discovered by the International Gamma-Ray Astrophysics Laboratory (INTEGRAL). The Suzaku observation was carried out between 2006 August 14 and 17, with a net exposure time of 97ks. The average X-ray spectrum of the source can be well described (χ_red²=0.99) with a continuum model typical for neutron stars i.e., a strongly absorbed power law continuum with a photon index of 0.676(42) and an exponential cutoff at 20.5(6)keV. The absorbing column is N_H=1.95(3)x10²⁴cm^–2. Consistent with earlier work, strong fluorescent emission lines of Fe Kα, Fe Kβ, and Ni Kα are observed. Despite the large N_H, no Compton shoulder is seen in the lines, arguing for a non-spherical and inhomogeneous absorber. Seen at an average 5-60keV absorbed flux of 3.4x10^–10erg/cm2/s, the source exhibits significant variability on timescales of hours.