Dusty Galaxies at the Highest Redshifts

TL;DR

This paper discusses the successful identification of high-redshift dusty galaxies using Herschel surveys, highlighting their abundance and implications for galaxy evolution models, and explores prospects for discovering even more distant galaxies.

Contribution

It demonstrates the effectiveness of red colour selection for high-redshift dusty galaxies and reports the discovery of galaxies at z>4, challenging existing galaxy evolution models.

Findings

HFLS3 at z=6.34 is the highest redshift dusty galaxy found.

Numerous galaxies at z>4 have been confirmed.

Detection of SPIRE-dropouts suggests potential for finding even higher redshift galaxies.

Abstract

We show that the use of red colour as the basis for selecting candidate high redshift dusty galaxies from surveys made with Herschel has proved highly successful. The highest redshift such object, HFLS3, lies at z=6.34 and numerous other sources have been found. Spectroscopic followup confirms that most of these lie at z>4. These sources are found in such numbers that they represent a challenge to current models of galaxy evolution. We also examine the prospects for finding dusty galaxies at still higher redshifts. These would not appear in the SPIRE surveys from Herschel but would be detected in longer wavelength, submm, surveys. Several such `SPIRE-dropouts' have been found and are now subject to followup observations.