The Dark Side of Reionization: Probing Cooling in the Early Universe

TL;DR

This paper discusses how future far-IR space telescopes can reveal the cooling processes of primordial clouds during the epoch of reionization, crucial for understanding early star formation and cosmic evolution.

Contribution

It proposes using next-generation far-IR observations to study molecular hydrogen and metal lines, unveiling cloud cooling mechanisms in the early universe.

Findings

Potential to observe primordial cloud cooling lines at 6 < z < 15

Building on Spitzer's detection of powerful H2 emission from shocks

Highlights the importance of far-IR spectroscopy for early universe studies

Abstract

Probing the growth of structure from the epoch of hydrogen recombination to the formation of the first stars and galaxies is one of the most important uncharted areas of observational cosmology. Far-IR spectroscopy covering $\lambda$ 100-500 microns from space, and narrow partial transmission atmospheric bands available from the ground, opens up the possibility of probing the molecular hydrogen and metal fine-structure lines from primordial clouds from which the first stars and galaxies formed at 6 < z $<$ 15. Building on Spitzer observations of unexpectedly powerful H2 emission from shocks, we argue that next-generation far-IR space telescopes may open a new window into the main cloud cooling processes and feedback effects which characterized this vital, but unexplored epoch. Without this window, we are essential blind to the dominant cloud cooling which inevitably led to star formation and cosmic reionization.