Observations of the redshifted 21 cm line of atomic hydrogen offer the potential of opening a new window into this epoch.
This will transform our understanding of the formation of the first stars and galaxies and of the thermal history of the Universe..
Observations of the redshifted 21 cm line of atomic hydrogen offer the potential of opening a new window into this epoch.
This will transform our understanding of the formation of the first stars and galaxies and of the thermal history of the Universe.Feb 23, 2018.
Modern physical cosmology is dominated by the Big Bang Theory which attempts to bring together observational astronomy and particle physics; more specifically, a standard parameterization of the Big Bang with dark matter and dark energy, known as the Lambda-CDM model..
21-cm cosmology in the 21st Century Abstract.
Imaging the Universe during the rst hundreds of millions of years remains one of the exciting challenges facing modern cosmology.
Observations of the redshifted 21 cm line of atomic hydrogen o er the potential of opening a new window into this epoch.
21 cm observations also have the potential to constrain fundamental cosmology and represent a path to a new level of precision cosmology.
Exploiting 21 cm observations for fundamental cosmology will be a challenging task and it is unclear how much can realistically be hoped for.
The 21 cm Background from the Cosmic Dark Ages:
Next we examine the cosmological context of the 21 cm signal.
We may express the 21 cm brightness temperature as a function of four variables Tb Tb(TK, xi, Jα, nH), where xi is the volume-averaged ionized fraction of hydrogen.
In calculating the 21 cm signal, we require a model for the global evolution of and fluctuations in these quantities.
