Embedded Files
The gas content of galaxies is determined by a balance of inflow, star formation, and outflows. However, it is difficult to directly observe gas flows in and out of galaxies, and the exact mechanisms behind the driving forces of a typical gas outflow are poorly understood. Gas kinematics can be used to identify outflows and trace radial flows of gas within galaxies. Optical integral field spectroscopy (IFS) is particularly powerful for identifying ionised outflows and discriminating between stellar and AGN feedback.
As a first step to understanding the radio emission in and the role of cosmic rays in star formation-driven galactic outflows, In Leslie et al. (2017), I studied six edge-on galaxies in the SAMI (Sydney-AAO Multi-object Integral field spectrograph) Galaxy Survey and FIRST (Faint Images of the Radio Sky at Twenty centimeters). I found that galaxies with outflows (identified through emission line diagnostics and kinematics) tend to have enhanced and spatially extended radio-emission compared to the extinction corrected Halpha SFRs.
Top: FIRST 1.4GHz contours on [NII]/Ha maps for 6 edge-on galaxies in SAMI. Bottom: A positive correlation between line ratios and velocity dispersion is good evidence for shocks (e.g. Rich et al. 2011). Figures from Leslie et al. 2017.
The energy source and dynamics of infrared luminous galaxy ESO 148-IG002
We separated the outflow (panel c) from the disk component (panel b) using gas kinematic information and study the strange emission line properties of this merging galaxy system.
A study published in Nature found that this galaxy has stars forming inside its outflow! Maiolino et al. (2017)
HST image of ESO 148-IG002 aka IRAS F23128-5919
Example WiFeS spectra and fit.
Google Sites
Report abuse