2011ApJ...735L..15O

One remaining open question regarding the physical properties of Lyα emitters (LAEs) is their dust content and evolution with redshift. The variety of results is large and with those reported by now it is difficult to establish clear relations between dust, other fundamental parameters of galaxies (star formation rate, metallicity, or age), and redshift. In this Letter, we report Herschel PACS-100 µm, PACS-160 µm, and Spitzer MIPS-24 µm detections of a sample of spectroscopically GALEX selected LAEs at z ∼ 0.3 and ∼1.0. Five out of ten and one out of two LAEs are detected in, at least, one PACS band at z ∼ 0.3 and ∼1.0, respectively. These measurements have a great importance given that they allow us to quantify, for the first time, the dust content in LAEs from direct FIR observations. MIPS-24 µm detections allow us to determine the IR properties of the PACS-undetected LAEs. We obtain that mid-IR/FIR-detected star-forming (SF) LAEs at z ∼ 0.3 have dust content within 0.75 ≲ A_1200 Å_ ≲ 2.0, with a median value of A_1200 Å_∼ 1.1. This range broadens up to 0.75 ≲ A_1200 Å_ ≲ 2.5 when considering the LAEs at z ∼ 1.0. Only one SF LAE is undetected both in MIPS-24 µm and PACS, with A_1200 Å_ ≲ 0.75. These results seem to be larger than those reported for high-redshift LAEs and, therefore, although an evolutionary trend is not clearly seen, it could point out that low-redshift LAEs are dustier than high-redshift ones. However, the diverse methods used could introduce a systematic offset in the results.