# Investigating High Mass X-ray Binaries at hard X-rays with INTEGRAL

## TL;DR

This study uses INTEGRAL data to analyze the X-ray properties of 58 high mass X-ray binaries, revealing their variability, duty cycles, and subclass distinctions, including bridging sources.

## Contribution

It provides a comprehensive quantitative overview of HMXB subclasses using hard X-ray observations and variability analysis, highlighting intermediate sources.

## Key findings

- Identified duty cycles and luminosity ranges for HMXB subclasses.
- Discovered intermediate properties bridging SgHMXBs and SFXTs.
- Quantified variability patterns across the sample.

## Abstract

The INTEGRAL archive developed at INAF-IASF Milano with the available public observations from late 2002 to 2016 is investigated to extract the X-ray properties of 58 High Mass X-ray Binaries (HMXBs). This sample consists of sources hosting either a Be star (Be/XRBs) or an early-type supergiant companion (SgHMXBs), including the Supergiant Fast X-ray Transients (SFXTs). INTEGRAL light curves (sampled at 2 ks) are used to build their hard X-ray luminosity distributions, returning the source duty cycles, the range of variability of the X-ray luminosity and the time spent in each luminosity state. The phenomenology observed with INTEGRAL, together with the source variability at soft X-rays taken from the literature, allows us to obtain a quantitative overview of the main sub-classes of massive binaries in accretion (Be/XRBs, SgHMXBs and SFXTs). Although some criteria can be derived to distinguish them, some SgHMXBs exist with intermediate properties, bridging together persistent SgHMXBs and SFXTs.