Andrew J. Fox

ESA/AURA Astronomer
Space Telescope Science Institute

Milky Way Halo Research Group


Andrew Fox is an ESA/AURA astronomer at the Space Telescope Science Institute (STScI) in Baltimore, Maryland, the scientific home of the Hubble Space Telescope and the James Webb Space Telescope. His research group focuses on galactic ecosystems and the role diffuse gas plays in them, particularly the Milky Way and the Magellanic Clouds. They make use of ultraviolet, optical, and radio spectroscopy to determine the physical and chemical properties of diffuse gas clouds, trace galactic inflows and outflows, and better understand how galaxies continue to form stars over cosmic timescale. At STScI, he is a member of the COS Instrument branch where he leads the User Support block, and he also serves as Chair of the Telescope Time Review Board (TTRB) for the Hubble Space Telescope. He previously coordinated the review of Director's Discretionary (DD) proposals for almost five years (see his STScI Directory Entry for more details). Before joining STScI, he worked at the Institute of Astronomy (IoA) in Cambridge, the European Southern Observatory (ESO) in Chile, and the Institut d'Astrophysique de Paris (IAP), and he was a student at the University of Wisconsin-Madison, and University College London (UCL).

Click here for my ADS record

Click for my Resume (pdf) and Publications (pdf)

Recent work

Gas Accretion book

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.

Galactic Center Outflow

I'm the Principal Investigator of two HST program totaling 70 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.

Magellanic Stream

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 extraordinary stream or the press releases described below.

Press Releases

Fermi Bubbles

The Galactic nuclear wind is feeding the giant Fermi Bubbles with new material. Our Galactic Center program has led to two NASA press releases, one in 2015 on the discovery of the wind in UV absorption (click here) and one in 2017 on the northern sky survey (click here ).

Magellanic System

This huge network of gas clouds on either side of the Magellanic Clouds holds clues to the ways that dwarf galaxies interact and feed their massive neighbors. We explore its origin using chemical composition analyses with Hubble and the Green Bank Telescope. See NASA press releases from 2013 and 2018


Smith Cloud

The enigmatic Smith Cloud is a massive infalling gas clump that is close to impacting the Galactic disk. Its origin is unknown. We used Hubble to measure its chemical compostion and kinematics and probe its source. See our 2016 NASA press release (click here).

Research Interests

Interstellar, circumgalactic, and intergalactic gas
High-velocity clouds (HVCs) and the Magellanic System
Quasar absorption line systems
Fermi Bubbles, galaxy inflows and outflows
Photoionization modeling of diffuse plasmas
Galaxy formation and evolution

Group Members


Trisha Ashley (postdoc)
David French (postdoc)
Elaine Frazer (analyst)
Camellia Magness (analyst)


Rongmon Bordoloi (now faculty at NC State)
Svea Hernandez (now postdoc at STScI)
Stephen Lucas (UCL)
Corbin Taylor (now at UMD)
Nimisha Kumari (now at IoA, Cambridge)
Jacqueline Antwi-Danso (now at Texas A&M)
Tanveer Karim (now at Harvard)

More information is on our group webpage.


Space Telescope Science Institute
3700 San Martin Drive, Baltimore, MD 21218
Office: +1 443 338 5083
Email: afox[at]