Dust properties of Lyman break galaxies at $z\sim3$

TL;DR

This study statistically analyzes the far-infrared and sub-millimeter properties of 22,000 Lyman break galaxies at z~3, revealing their IR spectral energy distributions and relation to star formation and stellar mass.

Contribution

It provides the first comprehensive IR SEDs of a large LBG sample at z~3, linking IR properties with UV and stellar parameters using advanced stacking techniques.

Findings

IRX is roughly constant across UV luminosity

IRX correlates with UV slope and stellar mass

LBGs at z~3 lie on the main sequence of star formation

Abstract

We explore from a statistical point of view the far-infrared (far-IR) and sub-millimeter (sub-mm) properties of a large sample of LBGs (22,000) at z~3 in the COSMOS field. The large number of galaxies allows us to split it in several bins as a function of UV luminosity, UV slope, and stellar mass to better sample their variety. We perform stacking analysis in PACS (100 and 160 um), SPIRE (250, 350 and 500 um) and AzTEC (1.1 mm) images. Our stacking procedure corrects the biases induced by galaxy clustering and incompleteness of our input catalogue in dense regions. We obtain the full IR spectral energy distributions (SED) of subsamples of LBGs and derive the mean IR luminosity as a function of UV luminosity, UV slope, and stellar mass. The average IRX is roughly constant over the UV luminosity range, with a mean of 7.9 (1.8 mag). However, it is correlated with UV slope, and stellar mass. We investigate using a statistically-controlled stacking analysis as a function of (stellar mass, UV slope) the dispersion of the IRX-UVslope and IRX-M* plane. Our results enable us to study the average relation between star-formation rate (SFR) and stellar mass, and we show that our LBG sample lies on the main sequence of star formation at z~3.