BeppoSAX Observations of the Atoll X-Ray Binary 4U0614+091

TL;DR

This paper presents the first simultaneous broad-band X-ray spectrum of the neutron star binary 4U0614+091, revealing a high-temperature Comptonized tail and evidence of disk reflection, with correlations similar to black hole systems.

Contribution

It provides the first simultaneous broad-band X-ray spectrum of 4U0614+091 and identifies spectral features and correlations comparable to black hole binaries.

Findings

Detection of a high-temperature (>220 keV) Comptonized tail.

Observation of a reflection feature consistent with disk reprocessing.

Correlation between photon index and reflection fraction similar to black hole systems.

Abstract

We report the first simultaneous measurement of the broad band X-ray (0.3-150 keV) spectrum of the neutron star x-ray binary 4U0614+091. Our data confirm the presence of a hard x-ray tail that can be modeled as thermal Comptonization of low-energy photons on electrons having a very high temperature, greater than 220 keV, or as a non-thermal powerlaw. We detected a spectral feature that can be interpreted as reprocessing, via Compton reflection, of the direct emission by an optically-thick disk and found a correlation between the photon index of the power-law tail and the fraction of radiation reflected which is similar to the correlation found for black hole candidate x-ray binaries and Seyfert galaxies.