Galactic Outflows: tracers of Massive Star feedback
Something amiss with star formation
Star formation is an inefficient process. The Kennicutt-Schmidt law shows that only ~1% of gas is converted into stars. When gas is converted into stars, it happens slower than would naively be thought. Further, simulations always form stars too soon, and too rapidly. Something must delay the buildup of stars.
Additionally, gas and metals are not confined to galactic disks. Recent work finds nearly half of the cosmic metals and baryons outside of galaxies. Massive stars produce metals and we do not observe massive stars outside of galaxies. Something must move gas from inside galactic disks and into the halo.
Energy and momentum from massive stars (so called "stellar feedback") may solve these problems. High-mass stars emit high energy photons and cosmic rays during their lifetimes, heating the gas, and dissociating molecular gas. These processes combine with energy from supernovae to drive turbulence in the interstellar medium and add to the gas pressure to counteract gravity, and slow star formation. The energy also accelerates gas and freshly synthesized metals out of star-forming regions and into the halos around galaxies. Massive stars drive the elegant self-regulation galaxies and establish the observed trends between galaxy properties.
My research is at the forefront of observing the amount of gas ejected out of galactic disks. I have established observational techniques to determine the metallicity, mass, energy and momentum of galactic outflows. These observations have cemented the importance of massive stars for driving galaxy evolution and establishing the properties of galaxies. Click on the buttons below to uncover more details about some of these topics.
Additionally, gas and metals are not confined to galactic disks. Recent work finds nearly half of the cosmic metals and baryons outside of galaxies. Massive stars produce metals and we do not observe massive stars outside of galaxies. Something must move gas from inside galactic disks and into the halo.
Energy and momentum from massive stars (so called "stellar feedback") may solve these problems. High-mass stars emit high energy photons and cosmic rays during their lifetimes, heating the gas, and dissociating molecular gas. These processes combine with energy from supernovae to drive turbulence in the interstellar medium and add to the gas pressure to counteract gravity, and slow star formation. The energy also accelerates gas and freshly synthesized metals out of star-forming regions and into the halos around galaxies. Massive stars drive the elegant self-regulation galaxies and establish the observed trends between galaxy properties.
My research is at the forefront of observing the amount of gas ejected out of galactic disks. I have established observational techniques to determine the metallicity, mass, energy and momentum of galactic outflows. These observations have cemented the importance of massive stars for driving galaxy evolution and establishing the properties of galaxies. Click on the buttons below to uncover more details about some of these topics.