VERITAS Observations of TeV Binaries

TL;DR

VERITAS has extensively observed TeV binary star systems, particularly LS I +61 303 and HESS J0632+057, revealing new insights into their gamma-ray emissions and identifying HESS J0632+057 as a binary system through TeV observations.

Contribution

This study provides the first identification of a binary system via TeV gamma-ray observations and offers detailed characterization of TeV emissions from LS I +61 303 and HESS J0632+057.

Findings

Detection of a emission break in the 10-200 GeV range for LS I +61 303

First TeV-based identification of HESS J0632+057 as a binary system

Extended observations improve understanding of TeV binary systems

Abstract

Since the commissioning of the array in Spring 2007, the VERITAS array (sensitive in the 0.1-50 TeV energy range) has acquired over 300 hours of observations investigating the TeV emission from X-ray binary star systems, in particular focusing on the known TeV binary targets LS I +61 303 and HESS J0632+057. Both TeV binaries have been monitored by VERITAS for several years and the resulting dataset is continuing to yield important results in the characterization of these poorly understood systems. We present these results, as well as the contemporaneous observations of these sources taken with Fermi-LAT and Swift-XRT. In the case of LS I +61 303, simultaneous observations taken with VERITAS and Fermi-LAT reveal a break in emission in the 10-200 GeV range. For HESS J0632 057, the extended VERITAS observations have allowed for the first identification of a binary system through TeV gamma-ray observations.