2007ApJ...659...76W

We present deep submillimeter imaging of two spectroscopically confirmed z∼6.5 Lyα emitters (LAEs) in the Subaru Deep Field. Although we reach the nominal confusion limit at 850 µm, neither LAE is detected at 850 or 450 µm; thus, we conclude that the LAEs do not contain large dust masses (<2.3x10⁸ and <5.7x10⁸ M_☉). The limit on their average L_FIR/L_UV ratios (≲35) is substantially lower than seen for most submillimeter-selected galaxies at z∼3 and is within the range of values exhibited by Lyman break galaxies. We place upper limits on their individual star formation rates of ≲248 and ≲613 M_☉/yr, and on the cosmic star formation rate density of the z∼6.5 LAE population of ≲5.0x10^–2 M_☉/yr/Mpc3. In the two submillimeter pointings, we also serendipitously detect seven sources at 850 µm that we estimate to lie at 1<z<5.