* Astronomy

Title: Chandra Observation of the Big Dipper X 1624-490
Authors: R. Iaria, G. Lavagetto, A. D'Ai', T. Di Salvo, N. R. Robba

We present the results of a 73 ks long Chandra observation of the dipping source X 1624-490. During the observation a complex dip lasting 4 hours is observed. We analyse the persistent emission detecting, for the first time in the 1st-order spectra of X 1624-490, an absorption line associated to \ion{Ca}{xx}. We confirm the presence of the \ion{Fe}{xxv} K_alpha and \ion{Fe}{xxvi} K_alpha absorption lines with a larger accuracy with respect to a previous XMM observation. Assuming that the line widths are due to a bulk motion or a turbulence associated to the coronal activity, we estimate that the lines have been produced in a photo-ionised absorber between the coronal radius and the outer edge of the accretion disk.

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