In 2017 Romeel Dave and I edited a book on Gas Accretion onto Galaxies, published by Springer. This is a contributed volume with 15 chapters written by 15 authors reviewing the inflow of gas onto galaxies. Find the chapters here.
I'm the Principal Investigator of three HST programs totaling 95 orbits to study the Galactic Center region in UV absorption. Our results dicussing the absorption-line properties of the biconical outflow at the center of the Milky Way are described in a series of papers in the Astrophysical Journal.
The Magellanic Stream is a giant tidal tail of gas stipped out the Magellanic Clouds and now orbiting the Milky Way. See the Annual Reviews of Astronomy & Astrophysics article I wrote with Elena D'Onghia on this enormous stream or the press releases described below.
The Galactic Center is surrounded by two giant Fermi Bubbles, containing a population of small outflowing clouds. Our Fermi Bubble program has led to two NASA press releases, one in 2015 and one in 2017, and an NRAO press release in 2025.
The titanic explosion that created the Fermi Bubbles also produced an ionization cone that appears to have heated the Magellanic Stream, causing elevated H-alpha emission and UV ionization ratios. This story was covered in 2020 by NASA, the ASTRO-3D center in Sydney and BBC News.
The Magellanic Clouds are surrounding by huge quantities of gas, including the famous Magellanic Stream, the Bridge, and a diffuse halo. We have been studying Magellanic gas for over a decade with the Hubble Spacee Telescope. See our series of NASA press releases from 2013, 2022, and 2024.
In 2019, we used observations from Hubble's Cosmic Origins Spectrograph (COS) to measure the rates at which the Milky Way is gaining and losing gas to its surroundings, finding an excess of inflow. This story was covered in 2019 by NASA, Phys.org and Universe Today.
The enigmatic Smith Cloud is a massive infalling gas cloud close to impacting the Galactic disk, where it may trigger new generations of star formation. Its origin is unknown. We used Hubble to measure its chemical compostion and probe its source. See our 2016 NASA press release.
The Leading Arm is a series of gas clouds connecting the Magellanic Clouds to the Milky Way. We found that its chemical composition is spatially variable, providing new clues on its origin. These results were featured in a 2018 NASA press release.
Space Telescope Science Institute
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ORCID: https://orcid.org/0000-0003-0724-4115