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We study the topology of the network of ionized and neutral regions that characterized the intergalactic medium during the Epoch of Reionization. Our analysis uses the formalism of persistent homology, which offers a highly intuitive and…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-29 Willem Elbers , Rien van de Weygaert

We explore the possibility of constraining model parameters of the Epoch of Reionization (EoR) from 21cm brightness temperature maps, using a combination of morphological descriptors constructed from the eigenvalues of the Contour Minkowski…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-19 Akanksha Kapahtia , Pravabati Chingangbam , Raghunath Ghara , Stephen Appleby , Tirthankar Roy Choudhury

We use morphological descriptors, Betti numbers and Contour Minkowski Tensor (CMT) on 21cm brightness temperature excursion sets, to study the ionization and heating history of the intergalactic medium (IGM) during and before the Epoch of…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-09 Akanksha Kapahtia , Pravabati Chingangbam , Stephen Appleby

We present the relation between the genus in cosmology and the Betti numbers for excursion sets of three- and two-dimensional smooth Gaussian random fields, and numerically investigate the Betti numbers as a function of threshold level.…

The evolution of topology and morphology of ionized or neutral hydrogen during different stages of the Epoch of Reionization (EoR) have the potential to provide us a great amount of information about the properties of the ionizing sources…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-23 Aadarsh Pathak , Satadru Bag , Saswata Dasgupta , Suman Majumdar , Rajesh Mondal , Mohd Kamran , Prakash Sarkar

We study the two-dimensional topology of the 21-cm differential brightness temperature for two hydrodynamic radiative transfer simulations and two semi-numerical models. In each model, we calculate the two dimensional genus curve for the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-13 Yougang Wang , Changbom Park , Yidong Xu , Xuelei Chen , Juhan Kim

During the EoR, the first stars and galaxies appear while creating ionized bubbles that will eventually percolate near z=6. These ionized bubbles and percolation process are nowadays under a lot of scrutiny since observations of the HI gas…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 Emilie Thélie , Dominique Aubert , Nicolas Gillet , Pierre Ocvirk

In the next decade, radio telescopes like the Square Kilometer Array (SKA) will explore the Universe at high redshift, and particularly during the Epoch of Reionisation (EoR). The first structures emerged during this epoch, and their…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Emilie Thélie , Dominique Aubert , Nicolas Gillet , Julien Hiegel , Pierre Ocvirk

During the Epoch of reionisation, the intergalactic medium is reionised by the UV radiation from the first generation of stars and galaxies. One tracer of the process is the 21 cm line of hydrogen that will be observed by the Square…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-29 Julien Hiegel , Emilie Thélie , Dominique Aubert , Jonathan Chardin , Nicolas Gillet , Pierre Galois , Nicolas Mai , Pierre Ocvirk , Rodrigo Ibata

We study the evolution of the hydrogen ionization field during the epoch of reionization (EoR) using semi-numerical simulations. By calculating the Minkowski functionals (MFs) of the 21cm brightness temperature field, which provides a…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-14 Zhaoting Chen , Yidong Xu , Yougang Wang , Xuelei Chen

This study presents a numerical analysis of the topology of a set of cosmologically interesting three-dimensional Gaussian random fields in terms of their Betti numbers $\beta_0$, $\beta_1$ and $\beta_2$. We show that Betti numbers entail a…

Descriptors play an important role in data-driven materials design. While most descriptors of crystalline materials emphasize structure and composition, they often neglect the electron density - a complex yet fundamental quantity that…

Materials Science · Physics 2025-06-18 Nathan J. Szymanski , Alexander Smith , Prodromos Daoutidis , Christopher J. Bartel

The Epoch of Reionization (EoR), when the first luminous sources ionised the intergalactic medium, represents a new frontier in cosmology. The Square Kilometre Array Observatory (SKAO) will offer unprecedented insights into this era through…

The Betti numbers are fundamental topological quantities that describe the k-dimensional connectivity of an object: B_0 is the number of connected components and B_k effectively counts the number of k-dimensional holes. Although they are…

Mathematical Physics · Physics 2009-11-11 Vanessa Robins

Using the largest cosmological reionization simulation to-date (~24 billion particles), we use the genus curve to quantify the topology of neutral hydrogen distribution on scales > 1 Mpc as it evolves during cosmological reionization. We…

Astrophysics · Physics 2009-03-02 Khee-Gan Lee , Renyue Cen , J. Richard Gott , Hy Trac

Persistent homology is a common technique in topological data analysis providing geometrical and topological information about the sample space. All this information, known as topological features, is summarized in persistence diagrams, and…

Methodology · Statistics 2022-04-05 Asael Fabian Martínez

We represent excursion sets of smooth random fields as unions of a topological basis consisting of a sequence of simply and multiply connected compact subsets of the underlying manifold. The associated coefficients, which are non-negative…

Statistics Theory · Mathematics 2025-07-11 Pravabati Chingangbam

We use the results of large-scale simulations of reionization to explore methods for characterizing the topology and sizes of HII regions during reionization. We use four independent methods for characterizing the sizes of ionized regions.…

Cosmology and Nongalactic Astrophysics · Physics 2012-05-11 Martina M. Friedrich , Garrelt Mellema , Marcelo A. Alvarez , Paul R. Shapiro , Ilian T. Iliev

Detecting redshifted 21cm emission from neutral hydrogen in the early Universe promises to give direct constraints on the epoch of reionization (EoR). It will, though, be very challenging to extract the cosmological signal (CS) from…

We compute the bispectra of the 21cm signal during the Epoch of Reionization for three different reionization scenarios that are based on a dark matter N-body simulation combined with a self-consistent, semi-numerical model of galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Anne Hutter , Catherine A. Watkinson , Jacob Seiler , Pratika Dayal , Manodeep Sinha , Darren J. Croton
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