CAREER: Charting the Cosmic Dawn with Next Generation 21cm Arrays

Arizona State University, Scottsdale AZ

Investigators

Abstract

Astronomers want to observe the Cosmic Dawn, when the first stars and galaxies formed. These observations would resolve many open questions about how galaxies came to be, but owing to the extreme distance, the time period has yet to be observed. Principal Investigator (PI) Jacobs and his team are working on instruments to observe the redshifted 21 cm radio signal emitted from hydrogen gas during the Cosmic Dawn. The low frequency radio signals are very faint as not only are the galaxies far away, but they are obscured by foreground galaxies in the nearby universe. PI Jacobs and his team will develop advanced instrument calibration tools and techniques for two 21cm cosmology instruments currently under construction, the Hydrogen Epoch of Reionization Array (HERA) and the Owens Valley Long Wavelength Array (OVRO-LWA). To broaden participation the PI will continue to mentor and provide stipends for students in both the Research Experience for Non-Traditional Undergraduates (RENTU) program and for his graduate students who are leading contributions to the Completely Hackable Amateur Radio Telescope (CHART) program. The graduate students provide kits and expert guidance to high school students and teachers so that they can build a radio telescope and observe hydrogen gas in the Milky Way. The systematic noise floor improvements will be addressed with drones, internal calibration sources, and laboratory measurements combined with advanced data analysis pipelines. The HERA power spectrum measurements will rule out exotic models and provide new constraints on canonical models of the first stars and galaxies. The PI will lead an OVRO-LWA cosmology program which aims to determine hydrogen 21 cm limits at redshifts 18 through 25 while also demonstrating techniques applicable on other instruments. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.