The flow of gas into and out of a galaxy regulates many of its features, such as its rate of star formation and chemical content. Computer simulations have allowed us to probe these gas flows in greater detail, but there still remains much to uncover. For example, on what scales does gas flow out of actively star-forming galaxies?
Outlining Galactic Outflows
Currently, computer simulations model the flows of gas leaving a galaxy, called galactic outflows, very generally. They are typically informed either by observations or large-scale physics. However, galactic outflows need to be modeled with much finer detail to grasp their full impact on galaxies, which means that observations of outflows need to probe much smaller scales than they currently do.
A near-ultraviolet image of the galaxy J1157 taken by the Hubble Space Telescope’s Cosmic Origins Spectrograph in acquisition mode. The white circle indicates the extent of the spectrograph’s imaging capability. [Wang et al. 2020]Typically, outflows are explored via absorption spectroscopy, which utilizes the fact that the spectra of light shining through a cloud of material will be imprinted with features unique to the cloud’s material. But this technique is only useful when we’re looking “down the barrel” of an ...