Cosmic variance of the 21-cm global signal

Chromatic effects in the 21 cm global signal from the cosmic dawn

The redshifted 21 cm brightness distribution from neutral hydrogen is a promising probe into the cosmic dark ages, cosmic dawn, and re-ionization. LOFAR’s Low Band Antennas (LBA) may be used in the frequency range 45 MHz to 85 MHz (30 > z > 16) to measure the sky averaged redshifted 21 cm brightness temperature as a function of frequency, or equivalently, cosmic redshift. These low frequencies ...

Global 21 cm signal experiments : A designer ’ s guide

Studying the sources of cosmic reionization with 21-cm fluctuations

We explore the ability of measurements of the 21-cm power spectrum during reionization to enable the simultaneous reconstruction of the reionization history and the properties of the ionizing sources. For various sets of simulated 21-cm measurements, we perform maximum likelihood fits in order to constrain the reionization and galaxy formation histories. We employ a flexible six-parameter model...

COSMIC REIONIZATION AND THE 21 cm SIGNAL: COMPARISON BETWEEN AN ANALYTICAL MODEL AND A SIMULATION

We measure several properties of the reionization process and the corresponding low-frequency 21 cm signal associated with the neutral hydrogen distribution, using a large volume, high-resolution simulation of cosmic reionization. The brightness temperature of the 21 cm signal is derived by postprocessing this numerical simulationwith a semianalytical prescription. Our study extends to high red...

The global 21-cm signal in the context of the high-z galaxy luminosity function

We build a new model for the global 21-cm signal that is calibrated to measurements of the high-z galaxy luminosity function (LF) and further tuned to match the Thomson scattering optical depth of the cosmic microwave background, τ e. Assuming that the z 8 galaxy population can be smoothly extrapolated to higher redshifts, the recent decline in best-fitting values of τ e and the inefficient hea...