TY  - JOUR
AU  - Villanueva-Domingo, P.
AU  - Mena, O.
AU  - Miralda-Escude, J.
PY  - 2020
DA  - 2020//
TI  - Maximum amplitude of the high-redshift 21-cm absorption feature
T2  - Phys. Rev. D
JO  - Physical Review D
SP  - 083502
EP  - 8pp
VL  - 101
IS  - 8
PB  - Amer Physical Soc
AB  - We examine the maximum possible strength of the global 21-cm absorption dip on the cosmic background radiation at high-redshift caused by the atomic intergalactic medium, when the Lyman-alpha coupling is maximum, assuming no exotic cooling mechanisms from interactions with dark matter. This maximum absorption is limited by three inevitable factors that need to be accounted for: (a) heating by energy transferred from the cosmic background radiation to the hydrogen atoms via 21-cm transitions, dubbed as 21-cm heating; (b) Ly alpha heating by scatterings of Ly alpha photons from the first stars; (c) the impact of the expected density fluctuations in the intergalactic gas in standard cold dark matter theory, which reduces the mean 21-cm absorption signal. Inclusion of this third novel effect reduces the maximum global 21-cm absorption by similar to 10%. Overall, the three effects studied here reduce the 21-cm global absorption by similar to 20% at z similar or equal to 17.
SN  - 2470-0010
UR  - https://arxiv.org/abs/1912.09488
UR  - https://doi.org/10.1103/PhysRevD.101.083502
DO  - 10.1103/PhysRevD.101.083502
LA  - English
N1  - WOS:000523343100006
ID  - Villanueva-Domingo_etal2020
ER  -