| Abstract : | Some of the accreting X-ray pulsars are reported to show a peculiar spectral feature at 10 keV, known also as
“The 10keV feature”. The feature has been reported in multiple observations of the same source by different
observatories, but not all the observations of any source consistently show the presence of it. This feature is
observed in sources with different accretion parameters and neutron star parameters, and there is no physical explanation for it. Moreover, in most cases, the 10 keV feature was detected in the combined spectral fitting of data from different instruments with a break in the spectral coverage in the 10-15 keV region. We have carried out a systematic investigation for the presence of the “10 keV feature” using NuSTAR observations of a large number of accreting X-ray pulsars. NuSTAR is a low background imaging-spectroscopic instrument that provides wide and unbroken spectral coverage around the 10 keV region. Spectra from a total of 45 observations of 24 different sources were fitted with a standard continuum model and are then inspected for the presence of a “10 keV feature”. Unlike the previous reports, we found the occurrence of the “10 keV feature” to be very rare. Details of our findings will be discussed in this talk. |
