Observation of variable pre-eclipse dips and disk winds in the eclipsing LMXB XTE J1710-281

TL;DR

This study reports the first detection of highly ionized iron in the X-ray spectrum of the eclipsing LMXB XTE J1710-281, revealing variable pre-eclipse dips and evidence of accretion disc winds through spectro-timing analysis.

Contribution

It presents the first observation of highly ionized Fe species and orbit-to-orbit evolution of dips, indicating dynamic changes in the accretion disc structure in XTE J1710-281.

Findings

Detection of highly ionized Fe lines indicating disc winds

Observation of orbit-to-orbit dip evolution

Spectral analysis showing partial covering ionized absorbers

Abstract

We report the first detection of highly ionized Fe species in the X-ray spectrum of the eclipsing and dipping Low Mass X-ray Binary XTE J1710-281. Using archival Chandra and Suzaku observations, we have carried out a spectro-timing analysis of the source during three different epochs. We compare the average orbital profile and obtain differences in pre-eclipse dip morphologies between different observation epochs. We observe an orbit to orbit evolution of the dips for the first time in this source in both the Chandra observations, reflecting changes in the structure of the accretion disc in timescales of hours. We further perform intensity resolved spectroscopy for both the Chandra and the Suzaku data to characterize the changes in the spectral parameters from the persistent to the dipping intervals. We find that the absorbers responsible for the dips, can be best described using a partially ionized partial covering absorber, with an ionization parameter, log($\xi$) of $\sim$2. The photon index of the source remained at $\sim$2 during both the Chandra and the Suzaku observations. In the 0.6-9 keV Suzaku spectra, we detect a broad 0.72 keV Fe L-alpha emission line complex and two narrow absorption lines at $\sim$6.60 keV and $\sim$7.01 keV. The highly ionized Fe line signatures, being an indicator of accretion disc-winds, has been observed for the first time in XTE J1710-281.