Expected submillimeter emission and dust properties of Lyman break galaxies at high redshift

We investigate the expected submillimeter emission and dust properties of t he Lyman break galaxies (LBGs) in the Hubble Deep Field. The SCUBA Deep Sur vey (Hughes et al.) provides an upper limit of the 850 mu m flux densities of the LBGs. With this constraint, we argue that a typical ultraviolet-to-f ar-infrared spectral shape of the high-redshift LBGs is rather close to a t emplate spectrum of low-reddening starburst galaxies in the local universe but different from that of heavily dust-enshrouded ultraluminous far-infrar ed (FIR) galaxies like Arp 220. We also evaluate the lower limit temperatur e of dust in LBGs assuming a single- and two-component-modified blackbody s pectrum. To estimate the total amount of energy reemitted in the FIR wavele ngth, we take two different approaches: the method of model fitting to the UV spectra of LBGs and an empirical method that uses the relationship betwe en the UV spectral shape and the UV/FIR flux ratio observed for local starb urst galaxies. Both methods give a lower limit temperature of similar to 40 K for the LBGs, which is higher than the typical dust temperature of local optical- and infrared-selected galaxies. This result is also supported by the comparison of the expected submillimeter flux of the LBGs with the cosm ic FIR background radiation. The high dust temperature may indicate the eff ective massive star formation or the different dust properties in the high- redshift LBGs.