Milky Way Halo Group (MWH)

sample image
21 cm H I observations of the Smith Cloud, a high-velocity cloud in the Galactic halo (Credit: Bill Saxton, NRAO/AUI/NSF)

Our research group studies the gaseous halo of the Milky Way to better understand the Galactic ecosystem and to measure the flows of baryons between the Galactic disk and halo. These flows play a key role in regulating the rate of star formation and provide a close-up case study of the baryon cycle around a star-forming galaxy. Our group is largely observational and focuses on multi-wavelength spectroscopy at UV, optical, IR, and radio wavelengths. 

We are part of the Low Density Universe community at STScI. We welcome new collaborators at all career stages. We're interested in questions such as:

  • How and where do baryons enter and exit the Milky Way? 
  • What are the physical and chemical properties of the gaseous Galactic halo?
  • How does the Magellanic System and Magellanic Stream impact the Milky Way?
  • How do the giant Fermi Bubbles at the Galactic Center probe nuclear feedback?
  • What is the time variation of the ionizing radiation field in the Galactic halo?

We address these questions using a wide range of observational programs using the Hubble Space Telescope and ground based telescopes. 

Website: The Milky Way Halo Research Group at STScI

Leads: Andrew Fox, Jason Tumlinson

Members: Trisha Ashley, Francie Cashman, David French, Christian Soto

Research Topics:

  • Local Group Galaxies
  • Galaxy Formation and Evolution
  • Interstellar Medium
  • Intergalactic/circumgalactic medium
  • Chemical Abundances

Seminars/Journal Club: Low Density Universe, Galaxies Journal Club

Related Missions & Instruments: HST, GBT, VLT/UVES, Keck/HIRES, Gemini/NIFS, GTC/MEGARA, LUVOIR