21cm Cosmology and the Cosmic Near Infrared Background
Abstract
The Near Infrared Cosmic Background (NIRCB) is a signal from all NIR emitting regions in the Universe. The unresolved part of the NIRCB signal might have been caused by Lyα photons from hydrogen gas excited by high energy photons from Population III (Pop III) stars that are redshifted to longer wavelengths. These stars have yet to be directly observed; therefore, we rely on indirect measurements like the global 21cm signal. A detection of the global 21 cm signal was archived by Bowman et al 2018, showing the spin temperature in absorption in the redshift range 15 ≤ z ≤ 20. We use theoretical star formation rate densities Ψ(z) as they evolve over cosmic time that match the observed 21cm signal, and calculate the corresponding NIRCB. We find that the models by Schauer et al. 2019 or the star formation rate densities by simulations from Jaacks et al. 2018 are not enough to account for the current upper NIRCBlimit estimate from Kashlinsky et al. 2005. PopII stars or some other Lyα producingsources could be a factor in the unresolved portion of the NIRCB. We acknowledgesupport from the UT Austin REU grant AST-1757983 (PI: Jogee) funded by the NSF REUand DOD ASSURE programs.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23510814H