1/31/2024 0 Comments Flux power![]() We note that these seven simulations span a wide range of reionization histories, with the strongly overdense run E.DC = 3D experiencing the earliest drop in the H i fraction. We label that simulation as "E.DC = 3." Figure 1 shows reionization histories for these seven realizations. The seven realizations include six random realizations (that we label A–F) and one variation of box E with the value for the fluctuation in the cosmic density on the scale of the simulation box (the so-called "DC mode") manually set to 3 σ (to produce a strongly overdense volume that can still be reasonably evolved to z ∼ 5). In smaller 40 h −1 cMpc volumes such variations are larger, and hence these boxes are more useful for our purposes. The largest CROC simulations were performed in 80 h −1 cMpc volumes, but volumes of such size are so close to the mean universe that variations between different realizations do not lead to interesting variations in the reionization histories. Specifically, we use seven realizations of 40 h −1 cMpc ≈ 60 cMpc simulation volumes. It is the latter usage that is of a particular value for this work. 2011) for each box size, and these random realizations can be used both as samples of different spatial locations in the universe (the primary, designed usage) and as models of different universes with somewhat different reionization histories (a secondary, serendipitous usage). Second, CROC simulations include several random realizations with variable DC modes (Gnedin et al. First, they provide a reasonable, albeit not perfect, match to the observed distributions of optical depths and dark gaps in the Ly α forest at 5 ≲ z ≲ 6 (Gnedin et al. ![]() CROC simulations have two properties that make them highly suitable for this project. 2. MethodologyĪs a plausible model of cosmic reionization we use simulations from the CROC project (Gnedin 2014 Gnedin & Kaurov 2014). As the observational data on high-redshift quasars (and, hence, on the high-redshift Ly α forest) are bound to explode with the next generation of optical telescopes, it is useful to consider what potential constraints can be obtained from the observations of the flux power spectrum at z ∼ 6. 2002) at redshifts 5 5, approaching the EoR, currently exist (Viel et al. In this paper we utilize the Cosmic Reionization on Computers (CROC) simulation suite to explore the evolution of one of the key statistical measures of the Ly α forest, its flux power spectrum (Croft et al. This allows it to be used as a probe of the EoR, as well as other astrophysical phenomena, such as the thermal nature of dark matter. ![]() While on large scales the Ly α forest can be well described by the large-scale structure in the Λ-cold-dark-matter cosmological model, on small scales it is dependent on the thermal history of the intergalactic medium (IGM). The Ly α forest, created by the resonant scattering of redshifted Ly α photons from distant quasars by neutral hydrogen along a line of sight, has been used to successfully probe this period. This period is when radiation from the first light sources reionized the neutral hydrogen. ![]() The Epoch of Reionization (EoR) is a critical period in the thermal history of our universe.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |