... ATNF Home . About ATNF . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Parkes radio telescope . ... The proportionality between the emission measure and the intensity of the Balmer H emission provides an estimate of the total number of ionising photons emitted, and hence on the number of massive, hot stars that produced them. This has become the standard technique to infer not only the star formation rate but also the initial mass function (IMF) of massive stars. ...