Jackie Champagne

Howdy! I'm Jackie, a fifth year graduate student at the University of Texas at Austin and a UT Graduate Fellow. I work with Professor Caitlin Casey on the formation of galaxy protoclusters at high redshift, focusing on submillimeter/radio interferometric observations. Characterizing the star formation histories in these prolific progenitors to modern galaxy clusters is vital to understanding the assembly of large-scale structure in the Universe.

Girl with the ALMA Tattoo

I grew up in Jackson, New Jersey. I love bagels, pizza, and the Jersey Shore, and I hate making left turns.

I earned my B.S. in physics and astrophysics in 2016 from Rutgers University, where I completed a bachelor's thesis under the advice of Prof. Chuck Keeton. As an undergraduate, I was an NSF-REU student at Cornell Univeristy working on gravitationally lensed submillimeter galaxies with Prof. Dominik Riechers, which was my first introduction to submillimeter observations! I was also a research intern under Dr. Fabian Walter at MPIA using ALMA data tosearch for continuum sources around z=6 quasars.

A budding interest in submillimeter observations and dusty galaxies led me to Prof. Caitlin Casey, with whom I now work at UT Austin. You can check out some research details under the research tab.

As I was learning about astronomy as a career option, what fascinated me most was radio interferometry and how it has revolutionized what we know about the long-wavelength Universe. To celebrate that passion, I tattooed a dish on my arm, so feel free to call me by my self-given nickname, Girl with the ALMA Tattoo.

My Research

Broadly, I am interested in the processes by which large-scale structures form and evolve along the cosmic timeline. In particular I use major submillimeter/millimeter/radio-wavelength facilities to trace things like molecular gas, atomic gas, and dust emission in the hopes of studying the physics behind extreme galaxies and how they are shaped by their environments.

My first graduate project built on my work with Dr. Fabian Walter at MPIA, in which I used ALMA Band 6 observations of z=6 quasars to search for dust continuum overdensities. Such an overdensity would suggest evidence for early clustering around massive quasars, and these have been found with other tracers such as [CII] and Lyman-alpha. Interestingly, we did not find a corresponding overdensity in dust emission, but it's important to keep in mind that a millimeter continuum search probes Gpc scales: a true overdensity may exist but its signal could be washed out. This result was published in ApJ in 2018, and we are working on spectroscopic followup to the sources we did find, in order to strengthen the argument that continuum can be used to search for such overdensities.

I also contributed to the ngVLA white papers, developing the science case for the next generation Very Large Array, or ngVLA. While the plans to build it are still beyond anyone's knowledge, I've been helping run simulated observations of CO up to J=4-3 in submillimeter galaxies to compare with ALMA's current capabilities. It turns out that a longer wavelength facility that matches some of ALMA's specs would allow us to study molecular gas not only in extreme systems but also regular star forming galaxies. Stay tuned for that!

For the last few years I've been focusing on observations of protoclusters, and more specifically the properties of the member dusty star-forming galaxies (DSFGs) therein. Are DSFGs ubiquitous in protoclusters? Do all protoclusters go through starburst periods? Can the molecular gas trigger simultaneous starburst events in structures several comoving Mpc across? Working with a famous protocluster core at z=2.5 in the COSMOS field, we have performed a full census of the molecular gas, dust, and stellar content, and have drawn exciting conclusions about the assembly of protoclusters across cosmic time.

Bibliography

"No Evidence for Millimeter Continuum Source Overdensities in the Environments of zgt6 Quasars," Champagne et al., 2018, ApJ, 867, 153

"Comprehensive Gas Characterization of a z=2.5 Protocluster: A Cluster Core Caught in the Beginning of Virialization?" Champagne et al., 2021, ApJ, 913, 110

Professional Activities

I'm interested in lots besides research! You can find a full CV here or take a look at my ADS record.

Teaching

In 2019 I was a team member for the ISEE Professional Development Program, for which we developed an undergraduate inquiry activity about galaxy spectra. Most recently I TAed for AST376(Sp20), Observational Techniques in Astronomy. I trained students to operate the 30-inch optical telescope at McDonald Observatory. I also TAed for AST307 (Sp18), Introduction to Astronomy for Non-Majors. I really enjoy teaching and I got a lot of hands-on experience in this group-based style of class.

Equity & Inclusion in Astronomy

As a woman in STEM and a global citizen in general, I am passionate about tackling institutional biases and unfair treatment in academia. I am a member of UT's Equity and Inclusion discussion group, which has hosted mentorship workshops, helped draft a new department Code of Conduct, and joined up with other campus organizations to host allyship workshops. I'm heavily involved in TAURUS, a nine-week summer research program designed for under-represented undergraduate students; I have helped organize workshops and seminars as well as student peer mentorship.

Astronomy on Tap

Astronomy on Tap is a (now international!) organization hosting astronomy-themed talks at local venues geared toward the public. Austin boasts a widely-attended chapter hosted at the North Door, where I co-host the monthly Astronomy in the News segment. I have given a couple talks on the magic of interferometry, available here.

Python for beginners

Developed for the aforementioned TAURUS program, I have designed a series of Jupyter notebooks containing step-by-step tutorials for Python beginners. The tutorial is aimed toward the first-time undergraduate unfamiliar with basic command-line work, but it is easy to jump ahead if you are simply looking for some Python basics. It contains instructions for the fundamental things like syntax, array manipulation, plotting, etc, as well as astropy and aplpy demonstrations geared specifically for astronomers. This is all available on my github.

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