Joseph Ribaudo, assistant professor of physics at Utica College, is part of a team of researchers who have discovered large quantities of cool gas surrounding modern galaxies.
While it has long been suspected that such fresh gas must fall onto galaxies to fuel star formation, previous observational limits had prevented direct empirical evidence of this circumgalactic gas. However, using the Cosmic Origins Spectrograph and the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope, this team of researchers was able to identify the gas by analyzing the absorption signatures of hydrogen in the spectra of very bright and distant objects known as quasars.
The research is exciting, Ribaudo said, because galaxies are forming stars over extended periods of time, but until now the fuel for that star formation had proven difficult to locate or analyze. Nicolas Lehner, a research associate professor at the University of Notre Dame, who presented the findings at the American Astronomical Society meeting, last week in Long Beach, Calif, leads the collaboration. The work, titled “The Bimodal Distribution of the Cool Circumgalactic Medium at z < 1,” has been submitted the Astrophysical Journal.
The work was funded by NASA and the National Science Foundation, and made use of the Hubble, Keck and Magellan telescopes. In addition to Lehner, co-authors include J. Christopher Howk from Notre Dame; Todd Tripp from the University of Massachusetts; Jason Tumlinson, Chris Thom and Andrew Fox from the Space Telescope Science Institute; J. Xavier Prochaska and Jess Werk from the University of California, Santa Cruz; John O’Meara from St. Michael’s College; and Ribaudo from Utica College.
Ribaudo earned a bachelor’s degree from Allegheny College, and a master’s and doctoral degree from the University of Notre Dame. He joined UC in August of 2011.
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