A STUDY OF THE LOW-MASS X-RAY BINARY DIP SOURCES XB 1916 - 053, XB 1323 - 619, X 1624 - 490 AND 4U 1746 - 371 OBSERVED WITH INTEGRAL
- Middle East Technical University, Physics Department, Inonu Bulvari 356531, Ankara (Turkey)
We detect dipping activity/modulations in the light curve of the four low-mass X-ray binaries in the 3-10 keV and 20-40 keV energy ranges. The spectral parameters derived from the fits to the International Gamma-Ray Astrophysics Laboratory data are consistent with hot coronal structures in these systems where we find a range of plasma temperatures 3.0-224.9 keV. The unabsorbed X-ray to soft gamma-ray fluxes between 4 keV and 200 keV are 5.9 x 10{sup -10} erg s{sup -1} cm{sup -2} for XB 1916 - 053, 3.3 x 10{sup -10} erg s{sup -1} cm{sup -2} for XB 1323 - 619, 21.6 x 10{sup -10} erg s{sup -1} cm{sup -2} for X 1624 - 490, and 11.0 x 10{sup -10} erg s{sup -1} cm{sup -2} for 4U 1746 - 371. The optical depth to Compton scattering, {tau}, varies in a range 4.4-0.002 consistent with electron densities n {sub e} < 1.4 x 10{sup 15} cm{sup -3}. In general, we find no significant difference in the dip and non-dip spectra in the ISGRI energy range (above 20 keV) for all the four sources. We only detect absorption differences between dipping and non-dipping intervals for XB 1916 - 053 and X 1624 - 490 in the JEM-X energy range. Fits in the 4-200 keV range including an additional photoionized absorber model for the two sources show that XB 1916 - 053 has the highest ionized absorber among the two.
- OSTI ID:
- 21255709
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 138, Issue 1; Other Information: DOI: 10.1088/0004-6256/138/1/50; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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