University Of Tasmania

File(s) under permanent embargo

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

journal contribution
posted on 2023-05-17, 09:44 authored by Fukui, Y, Furukawa, N, Dame, TM, Joanne Dawson, Yamamoto, H, Rowell, GP, Aharonian, F, Hofman, W, De Ona Wilhelmi, E, Minamidani, T, Kawamura, A, Mizuno, N, Onishi, T, Mizuno, A, Nagataki, S
We have discovered remarkable jet- and arc-like molecular features toward the rich and young stellar cluster Westerlund 2. The jet has a length of $\sim$100pc and a width of $\sim$10pc, while the arc shows a crescent shape with a radius of $\sim$30pc. These molecular features each have masses of $\sim$10 $^{4}M_{\solar}$, 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 a microquasar.


Publication title

Astronomical Society of Japan. Publications










School of Natural Sciences


Astronomical Soc Japan

Place of publication

C/O National Astronomical Observatory, Mitaka, Tokyo, Japan, 181

Rights statement

Copyright 2009 Astronomical Society of Japan

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the physical sciences