| dc.contributor.advisor | Sethi, Shiv K | |
| dc.contributor.author | Raste, Janakee | |
| dc.date.accessioned | 2020-12-11T10:01:53Z | |
| dc.date.available | 2020-12-11T10:01:53Z | |
| dc.date.submitted | 2019 | |
| dc.identifier.uri | https://etd.iisc.ac.in/handle/2005/4746 | |
| dc.description.abstract | The epoch of Cosmic Dawn and Reionization is one of the most important time periods of the
universe when first sources of radiation like stars and galaxies were formed, and they changed the
properties of their surrounding medium. 21 cm radiation emitted due to the hyperfine splitting of
ground state of neutral hydrogen is one of the most important probes to study the state and
dynamics of neutral medium during this epoch. I present an analytical formalism to compute the
fluctuating component of the 21 cm signal from CD/EoR.
I have used excursion set formalism to calculate the size distribution of randomly distributed selfionized
regions, and calculate the isotropic spin temperature profiles around them, taking into
account the effect of X‐rays and Ly‐alpha photons. I present an analytical formalism to compute the
two‐point correlation function for this topology, where small ionization bubbles are surrounded by
large and shallow spin temperature profiles, which can overlap with one another and merge with a
background value far away from any source. Using geometric and probabilistic arguments, I compute
the global 21 cm signal, its auto‐correlation and power spectrum in the redshift range 10 < z < 30.
Our results from this analytical formalism agree reasonably well with existing results in the literature
from N‐body simulations | en_US |
| dc.language.iso | en_US | en_US |
| dc.relation.ispartofseries | ;G29640 | |
| dc.rights | I grant Indian Institute of Science the right to archive and to make available my thesis or dissertation in whole or in part in all forms of media, now hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part
of this thesis or dissertation | en_US |
| dc.subject | Reionization | en_US |
| dc.subject | ionization bubbles | en_US |
| dc.subject.classification | Research Subject Categories::NATURAL SCIENCES::Physics::Astronomy and astrophysics::Astroparticle physics | en_US |
| dc.title | Analytical Formalism to Study the 21 cm Signal from Cosmic Dawn and Epoch of Reionization | en_US |
| dc.type | Thesis | en_US |
| dc.degree.name | PhD | en_US |
| dc.degree.level | Doctoral | en_US |
| dc.degree.grantor | Indian Institute of Science | en_US |
| dc.degree.discipline | Faculty of Science | en_US |
