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A study of selected low-mass X-ray binary dip sources observed with INTEGRAL

Balman, Şölen
I present archival data of the dipping LMXB systems, XB 1916-053, XB 1323-619, X1624-490, and 4U 1746-371obtained by the ISGRI and JEM-X detectors on-board the INTEGRAL Observatory. The spectral parameters derived from the fits to the data are consistent with hot coronal regions in these systems where the electron temperatures are in a range 4.9-18.8 keV with the exception of XB 1323-62 having an unbounded temperature. The optical depth to Compton scattering, tau is low and consistent with electron densities n(e) < 10 x 10(15) cm(-3). We interpret that the three of the dipping LMXBs in the scope of this work host hot extended large coronal structures which constitute a symmetric region on the disk responsible for the Comptonization in the systems. We find absorption differences between dipping and non-dipping intervals for XB 1916-053 and X 1624-490 in the JEM-X energy range. The dip and non-dip spectra in the ISGRI energy range (above 20 keV) show no significant difference four the sources. Fits including an additional photo-ionized absorber model for the two sources show that XB 1916-053 has the highest ionized absorber.