Tracing the FeII-NeII ratio within star forming dwarf galaxies: a Spitzer IRS archival study - AstrophysicsReport as inadecuate




Tracing the FeII-NeII ratio within star forming dwarf galaxies: a Spitzer IRS archival study - Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: Archival Spitzer observations of 41 starburst galaxies that span a wide rangein metallicity reveal for the first time a correlation between theFeII-NeII 26.0-12.8 micron ratio and the electron gas density as traced bythe 18.7-33.4 micron SIII ratio, with the FeII-NeII ratio decreasing withincreasing gas density. We also find a strong correlation between the gasdensity and the PAH peak to continuum strength. Using shock and photoionizationmodels, we see the driver of the observed FeII-NeII ratios is metallicity.The majority of FeII emission in low metallicity galaxies may beshock-derived, whilst at high metallicity, the FeII emission may be insteaddominated by contributions from HII and in particular from dense PDR regions.However, the observed FeII-NeII ratios may instead be following ametallicity-abundance relationship, with iron being less depleted onto grainsin low metallicity galaxies - a result that would have profound implicationsfor the use of iron emission lines as unambiguous tracers of shocks.



Author: B. O'Halloran, S. C. Madden, N. P. Abel

Source: https://arxiv.org/







Related documents