Understanding the Sources of Reionization of the Universe

Swara Ravindranath

CRESST/CUA,
Deputy Chief Scientist for Cosmic Origins Program at NASA GSFC

Wed, September 18, 2024 - 4:00 PM

Reionization marks an important phase in cosmic history when the Universe transformed from being mostly neutral and opaque to being fully ionized allowing the free flow of radiation. What sources are responsible for this transition is one of the key science questions being addressed in Cosmic Origins research. The absorption caused by the neutral intergalactic medium in the reionization epoch makes it nearly impossible to directly observe the ionizing radiation. Local analogs which have properties very similar to the first galaxies are excellent laboratories where we can study the production and escape of ionizing radiation in detail. In this talk, I will focus on the UV-optical spectra of local star-forming galaxies obtained with the Hubble Space Telescope that help to interpret the observations of distant, young galaxies in the reionization epoch from the Webb Space Telescope. NASA’s future flagship mission, the Habitable Worlds Observatory (HWO), will have the UV capabilities needed to make transformative progress through direct observations of ionizing radiation across cosmic time. I will conclude the talk with an overview of HWO and the opportunities to be involved in HWO through the Cosmic Origins Program.

 

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