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A broad iron line in the Chandra/HETG spectrum of 4U 1705-44

T. Di Salvo·R. Iaria·M. Mendez·L. Burderi·G. Lavagetto·N. R. Robba·L. Stella·M. van der Klis
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Abstract

We present the results of a Chandra 30 ks observation of the low mass X-ray binary and atoll source 4U 1705-44. Here we concentrate on the study of discrete features in the energy spectrum at energies below 3 keV, as well as on the iron Kalpha line, using the HETG spectrometer on board of the Chandra satellite. Below 3 keV, three narrow emission lines are found at 1.47, 2.0, and 2.6 keV. The 1.47 and 2.6 keV are probably identified with Ly-alpha emission from Mg XII and S XVI, respectively. The identification of the feature at 2.0 keV is uncertain due to the presence of an instrumental feature at the same energy. The iron Kalpha line at ~6.5 keV is found to be intrinsically broad (FWHM ~ 1.2 keV); its width can be explained by reflection from a cold accretion disk extending down to 15 km from the neutron star center or by Compton broadening in the external parts of a hot (~2 keV) Comptonizing corona. We finally report here precise X-ray coordinates of the source.

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T. Di Salvo, R. Iaria, M. Mendez, L. Burderi, G. Lavagetto, N. R. Robba, L. Stella, M. van der Klis. 2005-03-09. A broad iron line in the Chandra/HETG spectrum of 4U 1705-44. https://doi.org/10.1086/430130

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