FIR-detected Lyman break galaxies at z ~ 3: Dust attenuation and dust correction factors at high redshift

TL;DR

This study investigates the FIR emission of high-redshift Lyman break galaxies at z ~ 3, revealing their high dust obscuration and the limitations of current dust attenuation correction methods, and comparing these properties to similar galaxies at z ~ 1.

Contribution

First direct FIR detections of z ~ 3 LBGs showing their extreme dust obscuration and the inadequacy of UV-based dust correction methods at high redshift.

Findings

PACS-detected LBGs at z ~ 3 are ultra/luminous IR galaxies.

UV slope methods underestimate dust attenuation for these galaxies.

FIR emission and dustiness of LBGs increase with redshift.

Abstract

Lyman break galaxies (LBGs) represent one of the kinds of star-forming galaxies that are found in the high-redshift universe. The detection of LBGs in the FIR domain can provide very important clues on their dust attenuation and total SFR, allowing a more detailed study than those performed so far. In this work we explore the FIR emission of a sample of 16 LBGs at z ~ 3 in the GOODS-North and GOODS-South fields that are individually detected in PACS-100um or PACS-160um. These detections demonstrate the possibility of measuring the dust emission of LBGs at high redshift. We find that PACS-detected LBGs at z ~ 3 are highly obscured galaxies which belong to the Ultra luminous IR galaxies or Hyper luminous IR galaxies class. Their total SFR cannot be recovered with the dust attenuation factors obtained from their UV continuum slope or their SED-derived dust attenuation employing Bruzual & Charlot (2003) templates. Both methods underestimate the results for most of the galaxies. Comparing with a sample of PACS-detected LBGs at z ~ 1 we find evidences that the FIR emission of LBGs might have changed with redshift in the sense that the dustiest LBGs found at z ~ 3 have more prominent FIR emission, are dustier for a given UV slope, and have higher SFR for a given stellar mass than the dustiest LBGs found at z ~ 1.