Séminaire Univers / |
| « Seminumerical simulations of the epoch of helium reionization » |
|
Akanksha Kapahtia |
| The evolution of the intergalactic medium (IGM) in the post cosmic dawn era is characterized by two major phase transitions. The first of these transitions corresponds to the ionization of hydrogen and the second occurs at a later cosmic time due to ionization of singly ionized helium at z~3. A thorough modeling of the IGM is essential for studies that utilize the Lyman alpha forest at intermediate redshifts. Therefore it is important to model the impact of HeII reionization on the thermal and ionization state of the IGM. We present efficient seminumerical simulations of helium reionization that take into account the spatial patchiness of reionization and model the process of photoheating semi-analytically. We first obtain a dark matter density field and halo catalogue from N-body simulations and then model quasars as sources of HeII reionization which is consistent with the observed quasar clustering and luminosity function data. The resultant ionizing photon field is included in the Semi Numerical Code for ReionIzation with PhoTon Conservation (SCRIPT), which was originally developed for modeling hydrogen reionization. The corresponding thermal history of the IGM is modeled via a subgrid prescription. We show that our seminumerical procedure leads to a reasonable set of values of our free parameters which are consistent with observations. The efficiency of our procedure shows promising prospects for performing parameter estimation during HeII reionization. |
|
mardi 13 juin 2023 - 11:00 Salle du Conseil Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |