2006/09/19 by J. W. Keohane, Jonathan W. Keohane, W. T. Reach +4 · 3 citations
Physics and Astronomy · #Afterglow #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Infrared #Interstellar medium #Jet (fluid) #Laser-Plasma Interactions and Diagnostics #Molecular cloud #Physics #Stars #Supernova #astro-ph
paper · pdf · doi:10.1086/509311
published as Astrophys.J.654:938-944,2007 · 9 pages with embedded figures Accepted by the Astrophysical Journal
arxiv created 2006/09/19 · openalex publication_date 2007/01/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present near-infrared narrowband images of the supernova remnant W49 B, taken with the WIRC instrument on the Hale 200 inch (5 m) telescope on Mount Palomar. The 1.64 μm [Fe II] image reveals a barrel-shaped structure with coaxial rings, which is suggestive of bipolar wind structures surrounding massive stars. The 2.12 μm shocked molecular hydrogen image extends 1.9 pc outside of the [Fe II] emission to the southeast. We also present archival Chandra data, which show an X-ray jetlike structure along the axis of the [Fe II] barrel, flaring at each end. Fitting single-temperature X-ray emission models reveals an enhancement of heavy elements, with particularly high abundances of hot Fe and Ni, and relatively metal-rich core and jet regions. We interpret these findings as evidence that W49 B originated inside a wind-blown bubble ( R ~ 5 pc) inside a dense molecular cloud. This suggests that W49 B's progenitor was a supermassive star that could significantly shape its surrounding environment. We also suggest two interpretations for the jet morphology, abundance variations, and molecular hydrogen emission: (1) the explosion may have been jet driven, interacting with the molecular cavity (i.e., a gamma-ray burst); or (2) the explosion could have been a traditional supernova, with the jet structure being the result of interactions between the shock and an enriched interstellar cloud.