Detecting Lyman alpha emitters in the submillimetre

Using the results from a previously developed Lyman alpha/continuum production/transmission and dust enrichment model for Lyman alpha emitters (LAEs), based on cosmological smoothed particle hydrodynamics simulations, we assess the detectability of their dust-reprocessed submillimetre (submm) radiation. As supernovae (rather than evolved stars) control dust formation and destruction processes, LAEs are relatively dust-poor with respect to local galaxies: they have low dust-to-gas ratios (0.05 times the dust-to-gas ratio of the Milky Way) in spite of their relatively high metallicity, Z approximate to 0.1-0.5 Z(circle dot). Using the derived escape fraction of ultraviolet (UV) continuum photons, we compute the UV luminosity absorbed by dust and re-emitted in the far-infrared. The LAE submm fluxes correlate with their Lyman alpha luminosity: about (3, 1 per cent) at z = (5.7, 6.6) of the LAEs in our simulated sample (those with log L(alpha) > 43.1) would have fluxes at 850 mu m (the optimal band for detection) in excess of 0.12 mJy and will be therefore detectable at 5 Sigma with ALMA with an integration time of only 1 h. Such detections would open a new window on the physical conditions prevailing in these most distant galaxies.