CHAPTER 11     REDSHIFTS AND VELOCITY DISPERSIONS





                 SUMMARY OF THE BASIC CCF ROUTINES USED TO GET REDSHIFTS  AND

            VELOCITY DISPERSIONS



                 To cross correlate rows in a spectral map  with  a  template

            row use:



            MA        Masks maps and include template (output map has 1 extra

                      row)

            FT        Forward transforms

            BT        Backward transforms

            CR        Cross correlates maps with their template

            CN        Normalizes the CCF

            CQ        Finds the CCF peak (where derivative equals zero)



            For velocity dispersions:



            SM        Divides the object transform by template  transform  to

                      give the broadening transform

            SP        Fits a gaussian to the broadening peak

            REAL and COMPLEX files are used as storage registers  to  contain

            your results ie.

                      

                      OPTION    MAP     REAL     COMP

                      

                      FT        1       P(S(k))  S(k)

                      CR        2       P(SxT)   S(k)xT(k)

                      BT        3       S*T      S(x)*T(x)

                      CN        4       S*T      normalised

                      CQ    gets the redshifts:  MAPIC=3, MAPIR=4