Andrew J. Fox

ESA/AURA Astronomer
Space Telescope Science Institute

Milky Way Halo Research Group

Bio

Andy Fox is an ESA/AURA astronomer at the Space Telescope Science Institute (STScI) in Baltimore, Maryland and an Associate Research Scientist at the Johns Hopkins University. STScI is the scientific home of the Hubble Space Telescope and the James Webb Space Telescope. Andy currently serves as the Branch Deputy for the Instrument and Science Support Branch (ISSB) in the INS Division and is the chair of the Telescope Time Review Board (TTRB) for JWST. Andy founded and leads the Milky Way Halo Research Group, which focuses on understanding our home galaxy, particularly by studying its vast atmosphere of interstellar gas. 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). More information can be found on his STScI Directory Entry .

Click here for my publication list (ADS)

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


Research Highlights

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 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.

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 enormous 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 and one in 2017 on the northern sky survey.

Seyfert Flare

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.

Magellanic Gas

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.

Galactic Inflow & Outflow

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.

Smith Cloud

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.

Leading Arm

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.

Research Interests

Milky Way and Local Group galaxies: structure and evolution
Interstellar, circumgalactic, and intergalactic gas
High-velocity clouds (HVCs)
Quasar absorption line systems
Fermi Bubbles, galactic inflows and outflows
Galaxy formation and evolution

Group Members

Current

Francie Cashman (Professor at Presbyterian College)
David French (Senior Staff Scientist)
Sapna Mishra (Postdoc)
Ravi Sankrit (STScI Scientist)
Debopam Som (Senior Staff Scientist)

Former

Jacqueline Antwi-Danso (now postdoc in Toronto)
Trisha Ashley (now at Intel)
Rongmon Bordoloi (now faculty at NC State)
Elaine Frazer (senior staff scientist at STScI )
Svea Hernandez (now ESA/AURA astronomer at STScI)
Tanveer Karim (now postdoc in Toronto)
Dhanesh Krishnarao (now faculty at Colorado College)
Nimisha Kumari (now ESA/AURA astronomer at STScI)
Camellia Magness (former analyst)
Christian Soto (program coordinator at STScI)
Corbin Taylor (former summer student)

More information is on our group webpage.

Contact

Space Telescope Science Institute
3700 San Martin Drive, Baltimore, MD 21218
Office: +1 410 338 5083
Email: afox[at]stsci.edu
Web: www.stsci.edu/~afox/
ORCID: https://orcid.org/0000-0003-0724-4115