A peculiar jet and arc of molecular gas toward the rich and young stellar cluster Westerlund 2 and a TeV gamma ray source

Abstract

We have discovered remarkable jet- and arc-like molecular features toward the rich and young stellar cluster Westerlund2. The jet has a length of ~100 pc and a width of ~10 pc, while the arc shows a crescent shape with a radius of ~30 pc. These molecular features each have masses of ~10000 solar mass and show spatial correlations with the surrounding lower density HI gas. The jet also shows an intriguing positional alignment with the core of the TeV gamma ray source HESS J1023-575 and with the MeV/GeV gamma-ray source recently reported by the Fermi collaboration. We argue that the jet and arc are caused by an energetic event in Westerlund 2, presumably due to an anisotropic supernova explosion of one of the most massive member stars. While the origin of the TeV and GeV gamma-ray sources is uncertain, one may speculate that they are related to the same event via relativistic particle acceleration by strong shock waves produced at the explosion or by remnant objects such as a pulsar wind nebula or microquasar.

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• Fermi-LAT Search for Pulsar Wind Nebulae around gamma-ray Pulsars
• A spectroscopic investigation of early-type stars in the young open cluster Westerlund 2
• ALMA view of G0.253+0.016: Can cloud-cloud collision form the cloud?
• The X-ray light curve of the massive colliding wind Wolf-Rayet + O binary WR21a
• Evidence of jet-clump interaction: a flip of the radio jet head of 3C~84
• Multi-wavelength environment of the Galactic globular cluster Terzan 5
• Discovery of possible molecular counterparts to the infrared Double Helix Nebula in the Galactic center
• Suzaku Observation of the Diffuse X-Ray Emission from the Open Cluster Westerlund 2: a Hypernova Remnant?
• Connecting the ISM to TeV PWNe and PWNe candidates
• The jet and arc molecular clouds toward Westerlund 2, RCW 49, and HESS J1023-575; 12CO and 13CO (J=2-1 and J=1-0) observations with NANTEN2 and Mopra Telescope
• Galactic Structure Toward the Carina Tangent
• A study of the interstellar medium towards the unidentified dark TeV $\gamma$-ray sources HESS J1614-518 and HESS J1616-508
• Magnetohydrodynamic Simulations of the Formation of Molecular Clouds toward the Stellar Cluster Westerlund 2: Interaction of a Jet with Clumpy Interstellar Medium
• High Velocity HI Jet-like Feature Towards the SNR Candidate G351.7-1.2
• Investigation of Dense Gas Towards Relativistic Outflow Sources