Impact of halos on the simulated cosmic dawn 21-CM signal

Abstract

Cosmic Dawn (CD) and Epoch of Reionization (EoR) has eluded the observations so far, but with the future Square Kilometer Array (SKA) radio interferometer this will no longer be the case. The 21-cm line, with low excitation energy and low optical depth, is the best candidate to probe this era. There are lots of astrophysical processes taking place in the IGM during this period which will be imprinted on the fluctuations of 21cm brightness temperature. To interpret these fluctuations, one needs an accurate model of the 21cm signal that can be used to constrain the CD-EoR parameters. The publicly available simulations lack the accuracy that will be demanded by the upcoming high-resolution observations. The objective of this thesis project is to improve these simulations by understanding the approximations undertaken by them and then finding an efficient algorithm to incorporate all the astrophysical processes without making the simulation computationally heavy. We have incorporated X-ray heating on top of the existing ReionYuga simulation and initial results show a computationally efficient way to model this process. We have also conducted preliminary statistical analysis on the impact of using halos to calculate the photon flux fied. The end goal is to build a semi-numeric simulation that can be used to constrain the CD-EoR parameters by performing fourier domain (power spectrum, bispectrum) or real space (Largest cluster statistics, Minkowski functions) statistical analysis.