Recent star formation in the Lupus clouds as seen by Herschel
  We present a study of the star formation histories of the Lupus I, III, and
IV clouds using the Herschel 70-500 micron maps obtained by the Herschel Gould
Belt Survey Key Project. By combining the new Herschel data with the existing
Spitzer catalog we obtained an unprecedented census of prestellar sources and
young stellar objects in the Lupus clouds, which allowed us to study the
overall star formation rate (SFR) and efficiency (SFE). The high SFE of Lupus
III, its decreasing SFR, and its large number of pre-main sequence stars with
respect to proto- and prestellar sources, suggest that Lupus III is the most
evolved cloud, and after having experienced a major star formation event in the
past, is now approaching the end of its current star-forming cycle. Lupus I is
currently undergoing a large star formation event, apparent by the increasing
SFR, the large number of prestellar objects with respect to more evolved
objects, and the high percentage of material at high extinction (e.g., above
A_V=8 mag). Also Lupus IV has an increasing SFR; however, the relative number
of prestellar sources is much lower, suggesting that its star formation has not
yet reached its peak.
