  A 2-hour service-mode SCUBA observation of the gravitationally-lensed Lyman
break galaxy MS1512-cB58 resulted in a 3 sigma upper limit of 3.9 mJy at 850um.
A comparison of this upper limit with values expected from rest-UV/optical
measurements of extiction suggests that dust temperature (T_d) and/or
emissivity index (beta) in cB58 may be substantially higher than is seen in
local galaxies, or that the attenuation curve in cB58 may be even gentler than
the already quite mild SMC dust law. If dust temperature T_d and emissivity
index beta in cB58 are similar to those seen in local IRAS-seleceted galaxies,
then cB58's dust mass is M_d <~ 10^7.7 Msun and its star formation rate is SFR
<~ 10 Msun/yr (for q_0=0.1, H_0=75 km/s/Mpc). This SFR upper limit is lower
than the star formation rate measured from Halpha, thus giving further support
to the notion that (T_d, beta) values in cB58 are higher than those seen in
local galaxies. It thus appears that our understanding of dust in this
extensively studied Lyman break galaxy is poor, and observations at other
wavelentghs are needed to better understand dust at high redshift. Such
observations can be provided by the upcoming SIRTF mission for which cB58's
expected flux densities are calculated.
