Abstract Details
| Name: BIDISHA BANDYOPADHYAY Affiliation: UNIVERSITY OF DELHI Conference ID: ASI2017_590 Title : INVESTIGATING NEUTRAL HYDROGEN STRUCTURES DURING THE EPOCH OF REIONIZATION USING FRACTAL DIMENSION Authors and Co-Authors : T. Roy Choudhury,National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Ganeshkhind, Pune 411007, India T. R. Seshadri,Department of Physics and Astrophysics, University of Delhi, Delhi-110007, India Abstract Type : Poster Abstract Category : General Relativity and Cosmology Abstract : The clustering and lacunarities in density distributions can be chracterized using fractal dimensions. The generalized fractal dimensions is used to study the neutral hydrogen distribution (HI) during the epoch of reionization. The analysis is done on a simulated data of HI field which is created using a semi-numeric model of the ionized bubbles. We calculate the fractal dimensions for length scales ∼ 10h ^{-1} cMpc. We find that the HI field displays significant multifractal behaviour and is not consistent with homogeneity at these scales when the mass averaged fraction of neutral hydrogen <=0.5. This multifractal nature is completely driven by the shapes and distribution of the ionized regions. The fact that the fractal dimension is sensitive to the neutral fraction implies that it can be used for constraining the reionization history. We also observe that the fractal dimension is relatively less sensitive to the value of the minimum mass of ionizing halos when it is in the range ∼ 10^9 − 10^10 h^{−1} Solar Mass . Interestingly, the fractal dimension is very different when the reionization proceeds inside-out compared to when it is outside-in. Thus the multifractal nature of HI density field at high redshifts can be used to study the nature of reionization. |