Wide-field (sub)millimeter continuum surveys of protoclusters: Clues to the origin of the IMF

Recent (sub)millimeter continuum surveys of nearby star-forming regions have revealed a wealth of new, cold cloud fragments. Those which are small-scale (diameter < 10000 AU), starless, and gravitationally bound are good candidates for being the direct progenitors of protostars, i.e., the structures within which individual protostellar collapse is initiated. The mass spectrum of these protocluster condensations is reminiscent of the stellar initial mass function (IMF), suggesting the IMF is partly determined by cloud fragmentation at the pre-stellar stage of star formation.