Series: Astronomy Colloquium
Date: Wednesday 03-Dec-2025
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2400
Speaker: Prof. Blakesley Burkhart (Rutgers University)
Title: Tracing Molecular Hydrogen from the Solar Neighborhood to Cosmic Dawn
Far-ultraviolet (FUV) fluorescent emission from molecular hydrogen (H2) is a powerful tracer of the dynamic boundary layers where the interstellar medium transitions from atomic to star-forming molecular gas. In this talk, I will highlight how this diagnostic of molecular clouds enables us to trace the lifecycle of molecular gas—from the closest interstellar clouds to the most distant galaxies observed by JWST. Close to home, we have uncovered Eos, the nearest and largest molecular cloud on the sky at just 94 parsecs, the first molecular complex identified directly in H2 FUV fluorescence. Eos provides an unprecedented laboratory to study an ultra-close hot/cold interface region, multiphase molecular gas at the interface of extreme stellar feedback, and motivates future space missions in the FUV. At the opposite end of the distance ladder, I will present a theoretical framework for interpreting H2 FUV fluorescence in the distant Universe, applied to stacked JWST/NIRSpec spectra of galaxies at z = 7. These data show tantalizing evidence for H2 emission in galaxies during cosmic dawn. Together, these results demonstrate how FUV fluorescent H2 provides a powerful window on the life cycle of molecular gas—from the edge of our Local Bubble to cosmic dawn.
In-person colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer Dr. Richard Mushotzky. Lunch will normally be reserved for the speaker to talk to graduate students. Anyone asking a question during a talk is asked to raise their hand and be acknowledged before speaking. Contact Dr. Richard Mushotzky for details.
Colloquium Organizer:
Dr. Richard Mushotzky
Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
