Comprising about 95% of the universe, dark matter and dark energy have been notable research topics of the modern science. We can test our cosmological models and the nature of these dark components by investigating the large-scale inhomogeneity of the universe. The power spectrum of density fluctuations retains cosmological information and is an effective tool to study this large-scale structure. 21-cm intensity mapping surveys (such as CHIME and HIRAX) track neutral hydrogen in aggregate, but lose long wavelength line-of-sight modes to foregrounds. Using simulations, I examine a proposed solution: the cosmic tidal reconstruction, which exploits shear distortions in local power spectrum to recover these lost data. I test this algorithm against experimental challenges, and analytically explain its behavior. Another process to probe density fluctuations is through absorption lines in quasar spectra — the Lyman-alpha forest. Precise measurements of its 1D power spectrum become important as the observational data improve. I implement an iterative maximum likelihood estimator, which takes baseline estimates, masked regions and uneven noise in data into account, but demands more computational resources.
Host: Shilo Xia
Lunch will be served at 11:45 a.m. in WLC-245. RSVP is required. Please help us reduce trash by bringing your own mug and plate.
Sponsored by the Flint Fund, Yale Physics Department, Yale Wright Laboratory, and Yale University.