Searching
in the dark
In our work, we use ultraviolet absorption spectroscopy to study the diffuse, low-density gas that exists just outside of galaxies’ disks. To achieve this, we use quasars as our light source. Visible over vast cosmological distances, quasars tend to inhabit the centers of very active, young galaxies and are among the most luminous, powerful, and energetic objects known in the universe, emitting up to a thousand times the energy output of the Milky Way, which itself contains 200–400 billion stars. In order to connect the quasar absorption lines to the properties of the galaxies that host the foreground gas, we observe the spectra of thousands of galaxies using multislit optical spectroscpy from the ground.
Research theme
The Low-Redshift Circumgalactic Medium
WHAT IS THE TOTAL EXTENT, DENSITY, AND TEMPERATURE OF THE CIRCUMGALACTIC MEDIUM?
DO WE SEE EVIDENCE FOR GALAXY QUENCHING IN THE CIRCUMGALACTIC MEDIUM?
Project Leads: Dr. Kirill Tchernyshyov and Dr. Matthew Wilde (Ph.D. 2022)
We are surveying the circumgalctic medium of the largest sample of galaxies to date, covering an area more than 5 times the virial radius from potential host galaxies. Ultimately, this new survey will set the standard for the next decade of CGM studies by providing the best constraints on gas cooling times, and mass flow rates into and out of the CGM, both as a function of cosmic time and galaxy properties.
Explore our findings:
Projects
Research theme
The Disk/Halo Link: Synthesizing Gaseous Tracer Samples in the Milky Way
What is the mass and morphology of the clouds in the Milky Way halo?
How fast is gas accreting onto the disk and when will it form new stars?
Project Leads: Dr. Hannah Bish (Ph.D. 2022) and Bonni Choi (Ph.D. expected 2026)
Our own Milky Way halo is of great interest to us. Luckily, we have high quality data for hundreds of UV sightlines - stars and quasars - which enables a singular opportunity to resolve the hydrodynamics of accretion and outflow in unprecedented detail.
Explore our findings:
Projects
Research theme
Direct Comparisons with State-of-the-Art Simulations
What is the origin and fate of the gas in the circumgalactic medium?
Project Leads: Dr. Nicole Sanchez (Ph.D. 2022), Dr. Iryna Butsky (Ph.D. 2021), Akaxia Cruz (Ph.D. expected 2023), and Sam Garza (Ph.D. expected 2026)
Recent progress in hydrodynamical modeling has led to increasingly sophisticated treatments of diffuse halo gas that move well beyond the original envisioning of the Galactic fountain where spontaneous radiative instabilities cause clouds to cool and fall back down onto the disk ballistically. We collaborate with many groups running these sophisticated models to better understand the physics driving the gas flows through the circumgalactic medium.
Explore our findings:
Projects
ACCESS THE DATA
