2005/12/15 by B. O’Halloran, B. O'Halloran, Shobita Satyapal +2
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.1086/500529
published as Astrophys.J.641:795-800,2006 · 19 pages, 4 figures, accepted for publication in ApJ
arxiv created 2005/12/15 · openalex publication_date 2006/04/14 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
Archival observations of 18 starburst galaxies that span a wide range in metallicity reveal for the first time a correlation between the ratio of emission-line fluxes of [Fe II] at 26 μm and [Ne II] at 12.8 μm and the 7.7 μm PAH strength, with the [Fe II]/[Ne II] flux ratio decreasing with increasing PAH strength. We also find a strong correlation between the [Fe II]/[Ne II] flux ratio and the host galaxy metallicity, with the flux ratio decreasing with increasing metallicity. Since [Fe II] emission has been linked primarily to supernova shocks, we attribute the high [Fe II]/[Ne II] ratios in low-metallicity galaxies to enhanced supernova activity. We consider this to be a dominant mechanism for PAH destruction, rather than grain destruction in photoionized regions surrounding young massive stars. We also consider whether the extreme youth of the low-metallicity galaxies is responsible for the lack of PAH emission.