We present an in-depth study of the high mass X-ray binary (HMXB) GX 301−2 during its pre-periastron flare using data from the XMM-Newton satellite. The energy spectrum shows a power law continuum absorbed by a large equivalent hydrogen column on the order of 10 24 cm −2 and a prominent Fe Kα fluorescent emission line. Besides the Fe Kα line, evidence for Fe Kβ, Ni Kα, Ni Kβ, S Kα, Ar Kα, Ca Kα, and Cr Kα fluorescent lines is found. The observed line strengths are consistent with fluorescence in a cold absorber. This is the first time that Cr Kα is seen in emission in the X-ray spectrum of a HMXB. In addition to the modulation by the strong pulse period of ∼685 s the source is highly variable and shows different states of activity. We perform time-resolved as well as pulse-to-pulse resolved spectroscopy to investigate differences between these states of activity. We find that fluorescent line fluxes are strongly variable and generally follow the overall flux. The N H value is variable by a factor of 2, but not correlated to continuum normalization. We find an interval of low flux in the light curve in which the pulsations cease almost completely, without any indication of an increasing absorption column. We investigate this dip in detail and argue that it is most likely that during the dip the accretion ceased and the afterglow of the fluorescent iron accounted for the main portion of the X-ray flux. A similar dip was found earlier in RXTE data, and we compare our findings to these results.

We present results from two observations of the wind-accreting X-ray pulsar 4U 1907+09 using the Suzaku observatory. The broadband time-averaged spectrum allows us to examine the continuum emission of the source and the cyclotron resonance scattering feature at ∼19 keV. Additionally, using the narrow CCD response of Suzaku near 6 keV allows us to study in detail the Fe K bandpass and to quantify the Fe Kβ line for this source for the first time. The source is absorbed by fully-covering material along the line of sight with a column density of N H ∼ 2 × 10 22 cm −2 , consistent with a wind accreting geometry, and a high Fe abundance (∼ 3 − 4 × solar). Time and phase-resolved analyses allow us to study variations in the source spectrum. In particular, dips found in the 2006 observation which are consistent with earlier observations occur in the hard X-ray bandpass, implying a variation of the whole continuum rather than occultation by intervening material, while a dip near the end of the 2007 observation occurs mainly in the lower energies implying an increase in N H along the line of sight, perhaps indicating clumpiness in the stellar wind.

A normal outburst of the Be/X-ray binary system A0535+26 has taken place in August 2009. It is the fourth in a series of normal outbursts that have occured around the periastron passage of the source, but is unusual by starting at an earlier orbital phase and by presenting a peculiar double-peaked light curve. A first "flare" (lasting about 9 days from MJD 55043 on) reached a flux of 440 mCrab. The flux then decreased to less than 220 mCrab, and increased again reaching 440 mCrab around the periastron at MJD 55057. Target of Opportunity observations have been performed with INTEGRAL, RXTE and Suzaku. First results of these observations are presented, with special emphasis on the cyclotron lines present in the X-ray spectrum of the source, as well as in the pulse period and energy dependent pulse profiles of the source.

We analyzed an XMM-Newton observation of the low-mass X-ray binary and atoll source MXB 1728-34. The source was in a lowluminosity state during the XMM-Newton observation, corresponding to a bolometric X-ray luminosity of 5 × 10 36 d 2 5.1 kpc erg s −1 . The 1-11 keV X-ray spectrum of the source, obtained combining data from all the five instruments on-board XMM-Newton, is well fitted by a Comptonized continuum. Evident residuals are present at 6−7 keV, which are ascribed to the presence of a broad iron emission line. This feature can be equally well fitted by a relativistically smeared line or by a self-consistent, relativistically smeared reflection model. Under the hypothesis that the iron line is produced by reflection from the inner accretion disk, we can infer important information on the physical parameters of the system, such as the inner disk radius, R in = 25−100 km, and the inclination of the system, 44• < i < 60• .

We present broad band analysis of the Be/X-ray transient 1A 1118−61 by Suzaku at the peak of its 3rd observed outburst in January 2009 and 2 weeks later when the source flux had decayed by an order of magnitude. The continuum was modeled with a cutoffpl model as well as a compTT model, with both cases requiring an additional black body component at lower energies. We confirm the detection of a cyclotron line at ∼ 55 keV and discuss the possibility of a first harmonic at ∼ 110 keV. Pulse profile comparisons show a change in the profile structure at lower energies, an indication for possible changes in the accretion geometry. Phase resolved spectroscopy in the outburst data show a change in the continuum throughout the pulse period. The decrease in the CRSF centroid energy also indicates that the viewing angle on the accretion column is changing throughout the pulse period. Subject headings: X-rays: stars -X-rays: binaries -stars: pulsars: individual (1A 1118−61) -stars: magnetic fields Burst Alert Telescope BAT (Mangano et al. 2009;). It reached a peak flux of ∼ 500 mCrab in the 15-50 keV energy band. This last outburst was monitored with Swift and the Rossi X-ray Timing Explorer (RXTE ) as well as with two long Suzaku pointings and one observation with INTEGRAL during a flaring episode ∼ 50 days after the peak of the main