NSF Award
2406628
The Epoch of Reionization (EoR) begins when the first luminous objects in the Universe form and their intense ultraviolet emission starts to reionize the neutral hydrogen of the intergalactic medium (IGM). With continued emission of ionizing radiation, reionization fronts form gradually expanding bubbles around the luminous sources. The growth of these ionized bubbles is patchy in both time and space, but the bubbles eventually merge and the EoR ends. Astronomers have yet to study the EoR through the most direct method: tracing the neutral IGM itself through detection of the redshifted 21 cm line. The CO Mapping Array Project is a Line Intensity Mapping experiment using a spectral line other than 21 cm. A collaborative project between California Institute of Technology, University of Miami, and University of Maryland will duplicate the existing Pathfinder receiver and use it to perform a survey of rhe carbon monoxide (CO) line across the sky. The research team will work with the Caltech Education Office to develop material to teach students in underserved high schools about coding and astronomy. During the summer, the project will provide training to teachers to deliver this material and will support the teachers with classroom visits during the school year. <br/><br/>The field of 21 cm cosmology has the potential to probe the structure and evolution of the inter- galactic medium, from the Cosmic Dark Ages through to Cosmic Dawn, the Epoch of Reionization and beyond. There are many challenges to this work: a foreground-to-signal ratio spanning five orders of magnitude, strong radio frequency interference (RFI), and subtle instrumental systematic errors. The COMAP project expects to overcome these challenges. After the COMAP survey, the team will cross correlate the resulting CO temperature cube with observations of the same field by a 21 cm cosmology experiment, the Low Frequency Array. These experiments have very different systematic errors, RFI environments and foreground levels, and the planned cross-correlation will therefore be insensitive to these effects. The investigators forecast that the resulting constraint on the CO × HI power spectrum will be 30 times better than the best current limits on either CO or HI. This provides a path to the first unambiguous confirmation of the EoR-era 21 cm signal and a route to tighter constraints on the HI autocorrelation power spectrum alone.<br/><br/>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.
