Studying cosmic dawn using redshifted HI 21-cm signal: A brief review

A Bera, R Ghara, A Chatterjee, KK Datta… - Journal of Astrophysics …, 2023 - Springer
In this review article, we briefly outline our current understanding of the physics associated
with the HI 21-cm signal from cosmic dawn. We discuss different phases of cosmic dawn as …

Constraining the intergalactic medium at z ≈ 9.1 using LOFAR Epoch of Reionization observations

R Ghara, SK Giri, G Mellema, B Ciardi… - Monthly Notices of …, 2020 - academic.oup.com
We derive constraints on the thermal and ionization states of the intergalactic medium (IGM)
at redshift≈ 9.1 using new upper limits on the 21-cm power spectrum measured by the …

Probing early Universe through redshifted 21-cm signal: Modeling and observational challenges

AK Shaw, A Chakraborty, M Kamran, R Ghara… - Journal of Astrophysics …, 2023 - Springer
Cosmic dawn (CD) and the epoch of reionization (EoR) are the most important parts of
cosmic history during which the first luminous structures emerged. These first objects heated …

Constraining the state of the intergalactic medium during the Epoch of Reionization using MWA 21-cm signal observations

R Ghara, SK Giri, B Ciardi, G Mellema… - Monthly Notices of the …, 2021 - academic.oup.com
ABSTRACT The Murchison Widefield Array (MWA) team has derived new upper limits on the
spherically averaged power spectrum of the 21-cm signal at six redshifts in the range z≈ 6.5 …

beorn: a fast and flexible framework to simulate the epoch of reionization and cosmic dawn

T Schaeffer, SK Giri, A Schneider - Monthly Notices of the Royal …, 2023 - academic.oup.com
In this study, we introduce beorn (Bubbles during the Epoch of Reionization Numerical
Simulator), a publicly available python code that generates three-dimensional maps of the …

Imprints of fermionic and bosonic mixed dark matter on the 21-cm signal at cosmic dawn

SK Giri, A Schneider - Physical review D, 2022 - APS
The 21-cm signal from the epoch of cosmic dawn prior to reionization consists of a promising
observable to gain new insights into the dark matter (DM) sector. In this paper, we …

Large-scale simulations of H and He reionization and heating driven by stars and more energetic sources

MB Eide, B Ciardi, L Graziani, P Busch… - Monthly Notices of …, 2020 - academic.oup.com
We present simulations of cosmic reionization and reheating from z= 18 to z= 5,
investigating the role of stars (emitting soft UV-photons), nuclear black holes (BHs, with …

The 21-cm signal during the end stages of reionization

SK Giri, M Bianco, T Schaeffer, IT Iliev… - Monthly Notices of …, 2024 - academic.oup.com
During the epoch of reionization (EoR), the 21-cm signal allows direct observation of the
neutral hydrogen (H i) in the intergalactic medium (IGM). In the post-reionization era, this …

Prospects of constraining reionization model parameters using Minkowski tensors and Betti numbers

A Kapahtia, P Chingangbam, R Ghara… - … of Cosmology and …, 2021 - iopscience.iop.org
We explore the possibility of constraining model parameters of the Epoch of Reionization
(EoR) from 21cm brightness temperature maps, using a combination of morphological …

Deep learning approach for identification of H ii regions during reionization in 21-cm observations

M Bianco, SK Giri, IT Iliev… - Monthly Notices of the …, 2021 - academic.oup.com
ABSTRACT The upcoming Square Kilometre Array (SKA-Low) will map the distribution of
neutral hydrogen during reionization and produce a tremendous amount of three …