Using X‐ray observations to identify the particle acceleration mechanisms in VHE SNRs and “dark” VHE sources

Abstract

Very high energy (VHE) γ-ray observations have proven to be very successful in localizing Galactic acceleration sites of VHE particles. Observations of shell-type supernova remnants have confirmed that particles are accelerated to VHE energies in supernova blast waves; the interpretation of the γ-ray data in terms of hadronic or leptonic particle components in these objects relies nevertheless strongly on input from X-ray observations. The largest identified Galactic VHE source class consists of pulsar wind nebulae, as detected in X-rays. Many of the remaining VHE sources remain however unidentified until now. With X-ray observations of these enigmatic "dark" objects one hopes to solve the following questions: What is the astrophysical nature of these sources? Are they predominantly electron or hadron accelerators? And what is their contribution to the overall cosmic ray energy budget? The paper aims to provide an overview over the identification status of the Galactic VHE source population.

X‐ray observations of Galactic H.E.S.S. sources: An update

“…have been an important aspect in the past years. For many sources, pulsar wind nebula counterparts or counterpart candidates have been identified using X‐ray satellite observations, predominantly XMM‐Newton , Chandra , and Suzaku (e.g., Kargaltsev et al ; Mattana et al ; Pühlhofer ). In rare cases, binary systems or binary candidates have been identified as counterparts.…”