Redshift Horizon for Detecting the First Galaxies in Far-Infared Surveys

DE ROSSI, MARÍA EMILIA; BROMM, VOLKER

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2019

0004-637X

We explore the possibility of detecting the first galaxies with the next generation of space-based far infrared (FIR) telescopes by applying an analytical model of primordial dust emission. Our results indicate that FIR/sub-mm sources at z > 7 will experience a strong negative K-correction. Systems of a given virial mass would exhibit larger dust luminosities at higher z, as a consequence of the increase in dust temperature driven by the higher temperature floor set by the cosmic microwave background. In addition, high-z systems are more concentrated, which enhances the heating efficiency associated with stellar radiation. By analysing source densities as a function of z, and considering survey areas of 0.1 deg^2 and 10 deg^2, we find that the redshift horizon for detecting at least one source would be above z ∼ 7 for instrument sensitivities <0.1 − 0.5 μJy and <0.5 − 3.0 μJy, respectively, with the exact values depending on the nature of primordial dust. However, galaxy populations with higher than typical metallicities, star formation efficiencies and/or dust-to-metal ratios could relax such sensitivity requirements. In addition, the redshift horizon shows a significant dependence on the nature of primordial dust. We conclude that future FIR campaigns could play a crucial role in exploring the nature of dust and star formation in the early universe.