The BeppoSAX LECS X-ray spectrum of Hercules X-1

TL;DR

This paper reports BeppoSAX observations of Her X-1 revealing a blackbody component and emission feature at 0.94 keV, likely due to fluorescent excitation at the inner accretion disk edge, with phase-dependent behavior.

Contribution

First detailed 0.1-10 keV spectral analysis of Her X-1 during main on-state confirming specific spectral features and their likely origin.

Findings

Detection of a 0.093 keV blackbody component

Identification of a broad emission feature at 0.94 keV

Phase dependence suggests a common origin for spectral features

Abstract

We present 0.1-10 keV observations of Her X-1 obtained with the Low-Energy Spectrometer Concentrator instrument onboard the BeppoSAX satellite during the main on-state of the 35 day cycle. We confirm the existence of an intense 0.093 keV blackbody component and a broad emission feature at 0.94 keV. The pulse phase dependence of these components is similar, suggesting a common origin. This is most likely fluorescent excitation of moderately ionized ($\xi\sim$10--100) material located at the inner edge of the accretion disk.