Observations at 850um in Perseus clusters

Covering 3deg^2^, this submillimetre continuum survey for protostellar activity is second in size only to that of rho Ophiuchus (Johnstone et al., 2004ApJ...611L..45J). Complete above 0.4M_{sun}_ (5{sigma} detection in a 14" beam), we detect a total of 91 protostars and pre-stellar cores.

Of these, 80% lie in clusters, representative of star formation across the Galaxy. Two of the groups of cores are associated with the young stellar clusters IC 348 and NGC 1333, and are consistent with a steady or reduced star formation rate in the last 0.5Myr, but not an increasing one. In Perseus, 40-60% of cores are in small clusters (<50M_{sun}_) and isolated objects, much more than the 10% suggested from infrared studies.