http://arxiv.org/abs/1710.04820
We present results obtained from a Suzaku observation of the accretion powered X-ray pulsar GX 1+4. Broad-band continuum spectrum of the pulsar was found to be better described by a simple model consisting of a blackbody component and an exponential cutoff power-law than the previously used compTT continuum model. Though the pulse profile had a sharp dip in soft X-rays ($<$10 keV), phase-resolved spectroscopy confirmed that the dimming was not due to increase in photoelectric absorption. Phase-sliced spectral analysis showed the presence of a significant spectral modulation beyond 10 keV except for the dip phase. A search for the presence of cyclotron resonance scattering feature in the Suzaku spectra yielded a negative result. Iron K-shell (K$\alpha$ and K$\beta$) emission lines from nearly neutral iron ions ($<$Fe III) were clearly detected in the source spectrum. A significant K$\alpha$ emission line from almost neutral Ni atoms was detected for the first time in this source. We estimated the iron abundance of $\sim$80 % of the solar value and Ni/Fe abundance ratio of about two times of the solar value. We searched for a iron Ly$\alpha$ emission line and found a significant improvement in the spectral fitting by inclusion of this line.
Y. Yoshida, S. Kitamoto, H. Suzuki, et. al.
Mon, 16 Oct 17
31/59
Comments: 19 pages, 12 figures, 4 tables