Galaxies and the Circumgalactic Medium (GCGM)

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Image of the Hubble Ultra Deep Field where the blue color represents the NUV, green the optical, and red the NIR. (Credit: NASA, ESA, H. Teplitz (IPAC/Caltech), M. Rafelski (STScI), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI))

The Galaxies and the Circumgalactic Medium group (GCGM) at the Space Telescope Science Institute (STScI) is a collaboration between staff scientists and postdocs at STScI and Johns Hopkins University. The focus of this research group is to study the formation and evolution of galaxies with an emphasis on the interchange of gas between galaxies and their surroundings. We typically address this by characterizing the physical properties of the galaxies and the CGM (e.g. chemical abundances, star formation, density, structure). When possible, we connect the gas observed in absorption back to the galaxies observed in emission. While this is our primary focus, our interests are diverse and our research spans many topics in galaxy evolution.

We are involved in a wide range of observational programs using the Hubble Space Telescope (HST), the James Webb Space Telescope (JWST), and ground based telescopes such as Keck, Very Large telescope (VLT), and Atacama Large Millimeter Array (ALMA). 

Lead: Marc Rafelski

Members (not exhaustive): Alex Beckett, Kalina Nedkova, Grecco Oyarzun, Mitchell Revalski, Ben Sunnquist

Research Topics:

  • Galaxy Formation and Evolution
  • Circumgalactic Medium
  • Intergalactic Medium
  • Astrochemistry, Chemical Abundances
  • Galaxy Accretion
  • Galaxy Outflows
  • Star Formation, Histories, and Evolution
  • Galaxy Structure
  • Galaxy Kinematics
  • High-Redshift Galaxies
  • AGN and Quasars
  • Quasar Absorption Line Spectroscopy 
  • Galaxy Groups and Clusters
  • Lyman Continuum Escape


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

Related Missions & Instruments: HST, JWST, Keck, VLT, ALMA, VLA

Related Programs: MUDF, UVCANDELS, CANDELS, UVUDF, PASSAGE, PIE, CEERS