Observations of Bow Shocks of Runaway Stars with H.E.S.S

Abstract

Runaway stars form bow shocks by sweeping up interstellar matter in their direction of motion. Theoretical models predict a spectrally wide non-thermal component reaching up to gamma-ray energies at a flux level detectable with current instruments. They were motivated by a detection of non-thermal radio emission from the bow shock of BD$+43^{\circ }3654$ and a possible detection of non-thermal X-rays from AE Aurigae. A search in the high-energy regime using data from \textit{Fermi}-LAT resulted in flux upper limits for 27 candidates listed in the first E-BOSS catalogue. We perform the first systematic search for TeV emission from bow shocks of runaway stars. Using all available archival H.E.S.S. I data we search for very-high-energy gamma-ray emission at the positions of bow shock candidates listed in the second E-BOSS catalogue. This catalogue comprises 73 bow shock candidates, 32 of which have been observed with the H.E.S.S. telescopes. None of the observed bow shock candidates shows significant emission in the H.E.S.S. energy range. The resulting upper limits are used to constrain current models for non-thermal emission from these objects.

5 pages, 4 figures, Contribution to the 6th International Symposium on High Energy Gamma-Ray Astronomy (Gamma2016), July 11-15, 2016, Heidelberg, Germany. To be published in the AIP Conference Proceedings

References in corpus (6)

• A Monte Carlo Template based analysis for Air-Cherenkov Arrays
• E-BOSS: An Extensive stellar BOw Shock Survey. II. Catalogue second release
• AE Aurigae: first detection of non-thermal X-ray emission from a bow shock produced by a runaway star
• Systematic search for high-energy gamma-ray emission from bow shocks of runaway stars
• Search for Diffuse X-rays from the Bow Shock Region of Runaway Star BD+43${}^{\circ }$3654 with Suzaku
• Modeling non-thermal emission from stellar bow shocks