Interpreting the Global 21-cm Signal from High Redshifts. I. Model Independent Constraints

Abstract

The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even in the best case scenario, in which the signal is accurately extracted from the foregrounds, that it will provide more than crude estimates of when the Universe's first stars and black holes form. In contrast to previous work, which has focused on predicting the 21-cm signatures of the first luminous objects, we investigate an arbitrary realization of the signal, and attempt to translate its features to the physical properties of the IGM. Within a simplified global framework, the 21-cm signal yields quantitative constraints on the Lyman-alpha background intensity, net heat deposition, ionized fraction, and their time derivatives, without invoking models for the astrophysical sources themselves. The 21-cm absorption signal is most easily interpreted, setting strong limits on the heating rate density of the Universe with a measurement of its redshift alone, independent of the ionization history or details of the Lyman-alpha background evolution. In a companion paper we extend these results, focusing on the confidence with which one can infer source emissivities from IGM properties.

10 pages, 6 figures, accepted for publication in ApJ

References in corpus (18)

• LOFAR: The LOw-Frequency ARray
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from the WMAP data
• A luminous quasar at a redshift of z = 7.085
• Formation of Supermassive Black Holes by Direct Collapse in Pregalactic Halos
• The Global 21 Centimeter Background from High Redshifts
• 21 cm fluctuations from inhomogeneous X-ray heating before reionization
• Studying Reionization with Ly-alpha Emitters
• Energy Feedback from X-ray Binaries in the Early Universe
• Quasistars: Accreting black holes inside massive envelopes
• Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array
• Science with a lunar low-frequency array: from the dark ages of the Universe to nearby exoplanets
• Power spectrum extraction for redshifted 21-cm epoch of reionization experiments: the LOFAR case
• Lyman-alpha Emitters During the Early Stages of Reionization
• The Scattering of Lyman-series Photons in the Intergalactic Medium
• Time-evolution of ionization and heating around first stars and miniquasars
• Spin Exchange Rates in Electron-Hydrogen Collisions
• Spin Exchange Rates in Proton-Hydrogen Collisions
• The Spin-Resolved Atomic Velocity Distribution and 21-cm Line Profile of Dark-Age Gas

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