Abstract
The observations in the submm/mm range are important to study the dust properties in the high redshift regime. FIR to mm observations show that most of the energy generated in star formation at z > 1 is absorbed by dust, which re-emits the energy at FIR wavelengths, a spectral range that is red-shifted into the transparent submm/mm atmospheric windows. We studied a sample of quasars with redshifts between 1.5 < z ≤ 6.4 and with observations in the submm/mm range. We found the FIR/UV ratio decreases at higher redshifts, indicating a dust mass evolution at z > 5.
