A connection between accretion state and $\text{Fe K absorption}$ in an accreting neutron star: black hole-like soft state winds?

Abstract

High resolution X-ray spectra of accreting stellar mass Black Holes reveal the presence of accretion disc winds, traced by high ionisation Fe K lines. These winds appear to have an equatorial geometry and to be observed only during disc dominated states in which the radio jet is absent. Accreting neutron star systems also show equatorial high ionisation absorbers. However, the presence of any correlation with the accretion state has not been previously tested. We have studied EXO 0748-676, a transient neutron star system, for which we can reliably determine the accretion state, in order to investigate the Fe K absorption/accretion state/jet connection. Not one of twenty X-ray spectra obtained in the hard state revealed any significant Fe K absorption line. However, intense Fe $\mathrm{XXV}$ and Fe $\mathrm{XXVI}$ (as well as a rarely observed Fe $\mathrm{XXIII}$ line plus S $\mathrm{XVI}$; a blend of S $\mathrm{XVI}$ and Ar $\mathrm{XVII}$; Ca $\mathrm{XX}$ and Ca $\mathrm{XIX}$, possibly produced by the same high ionisation material) absorption lines ($E{W}_{\mathrm{Fe}\mathrm{XXIII}-\mathrm{XXV}}=31\pm 3$ eV, $E{W}_{\mathrm{Fe}\mathrm{XXVI}}=8\pm 3$ eV) are clearly detected during the only soft state observation. This suggests that the connection between Fe K absorption and states (and anticorrelation between the presence of Fe K absorption and jets) is also valid for EXO 0748-676 and therefore it is not a unique property of black hole systems but a more general characteristic of accreting sources.

Accepted for publication in MNRAS Letters

References in corpus (7)

• The magnetic nature of disk accretion onto black holes
• Evaluating Spectral Models and the X-ray States of Neutron-Star X-ray Transients
• On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
• Black hole-like hysteresis and accretion states in neutron star low mass X-ray binaries
• Variations in the dip properties of the low-mass X-ray binary XB 1254-69 observed with XMM-Newton and INTEGRAL
• Properties of the ionised plasma in the vicinity of the neutron-star X-ray binary EXO 0748-676
• Dynamical constraints on the neutron star mass in EXO 0748-676

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