First multi-redshift limits on post-epoch of reionization 21cm signal from z = 1.96-3.58 Using uGMRT

Chakraborty, A and Datta, A and Roy, N and Bharadwaj, S and Choudhury, TR and Datta, KK and Pal, S and Choudhury, M and Choudhuri, S and Dutta, P and Sarkar, D (2021) First multi-redshift limits on post-epoch of reionization 21cm signal from z = 1.96-3.58 Using uGMRT. In: Astrophysical Journal Letters, 907 (1).

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Abstract

Measurement of fluctuations in diffuse HI 21 cm background radiation from the post-reionization epoch (z � 6) is a promising avenue to probe the large-scale structure of the universe and understand the evolution of galaxies. We observe the European Large Area ISO Survey-North 1 (ELAIS-N1) field at 300-500 MHz using the upgraded Giant Meterwave Radio Telescope (uGMRT) and employ the "foreground avoidance"technique to estimate the HI 21 cm power spectrum in the redshift range z = 1.96-3.58. Given the possible systematics that may remain in the data, we find the most stringent upper limits on the spherically averaged 21 cm power spectra at k � 1.0 Mpc-1 are (58.87 mK)2, (61.49 mK)2, (60.89 mK)2, and (105.85 mK)2 at z = 1.96, 2.19, 2.62, and 3.58, respectively. We use this to constrain the product of neutral HI mass density (ΩHI) and HI bias (bHI) to the underlying dark matter density field, ΩHIbHI, as 0.09, 0.11, 0.12, and 0.24 at z = 1.96, 2.19, 2.62, and 3.58, respectively. To the best of our knowledge these are the first limits on the HI 21 cm power spectra at the redshift range z = 1.96-3.58 and would play a significant role to constrain the models of galaxy formation and evolution. © 2021. The American Astronomical Society.

Item Type:	Journal Article
Publication:	Astrophysical Journal Letters
Publisher:	IOP Publishing Ltd
Additional Information:	The copyright of this article belongs to IOP Publishing Ltd
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	26 Feb 2021 10:25
Last Modified:	26 Feb 2021 10:25
URI:	http://eprints.iisc.ac.in/id/eprint/68015

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