Journal Article/Contribution to a conference proceedings

PUBDB-2023-04219

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png An updated view of the VHE gamma-ray sky around thestellar cluster Westerlund 2 with the H.E.S.S. experiment

Holch, T. L. (Corresponding author)DESY* ; de Ona Wilhelmi, E. M.DESY* ; HESS Collaboration (Collaboration author)

2023
SISSA Trieste

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Please use a persistent id in citations: doi:10.22323/1.444.0778  doi:10.3204/PUBDB-2023-04219

Abstract: Since the last H.E.S.S. publication on the stellar cluster Westerlund 2 in 2011, the H.E.S.S. dataseton this region has increased more than three-fold in exposure to ∼ 220 h of total observation time.By applying a novel approach to correct for atmospheric variations in IACT data, the commonlyapplied data quality selection criteria can be adapted to exploit as much of this dataset as possible.In combination with current analysis techniques, it is furthermore possible to disentangle andbetter characterise this complex region of the gamma-ray sky. Applying an extensive 3D fittingprocedure, we find three distinct VHE gamma-ray sources in the vicinity of Westerlund 2, adding anew emission region to the previously reported sources HESS J1023−575 and HESS J1026−582.Even though the sources partly overlap, their spectral indices differ from one another, providingnew clues on the relativistic particle acceleration and propagation in the region around the massivestar cluster. The new source component shows an elongated morphology that seems to emergefrom the star cluster, following the multi-parsec-scale CO jet cloud initially found in NANTENdata as reported in 2009.

Keyword(s): gamma ray: VHE ; star: cluster ; particle: relativistic ; star: massive ; particle: acceleration ; HESS ; spectral ; carbon ; oxygen ; atmosphere ; overlap ; propagation ; quality ; cloud

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Contributing Institute(s):

1. High Energy Steroscopic System (Z_HESS)

Research Program(s):

1. 613 - Matter and Radiation from the Universe (POF4-613) (POF4-613)

Experiment(s):

1. High Energy Stereoscopic System

Appears in the scientific report 2023

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Database coverage:
; ; ; ; DOAJ Seal

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