AIPS HELP file for SPECINDX in 31DEC25

As of Fri Nov 14 14:25:02 2025

HELP SECTION

SPECINDX
Type: Adverb (Real)
Use:  Spectral index defined so that the flux is proportional to
             (frequency) ^ (spectral index)
      In full detail:

            log(T(f)/T(f0) = S * log(f/f0) + C(1) * (log(f/f0))^2
               + C(2) * (log(f/f0))^3 + C(3) * (log(f/f0))^4

      where S is SPECINDEX and C is SPECURVE, f0 is 1 GHz for
      simplicity, and all logs are base 10.  It is unlikely for you to
      have reliable values for SPECURV(3); SETJY uses only through
      SPECURVE(2) for the basic flux calibration sources.
Tasks:
   BLCHN.........Compute closure offset corrections on a channel-by-
                 channel basis.  SPECINDX is used to remove a slope from
                 the derived spectrum of baseline corrections.
   BPASS.........Computes spectral bandpass correction table.
                 SPECINDX is used to remove a slope from the derived
                 bandpass amplitude spectrum.
   CPASS.........Computes polynomial spectral bandpass correction table.
                 SPECINDX is used to remove a slope from the derived
                 bandpass amplitude spectrum.
   EVAUV.........Subtracts & divides a model into UV data, does
                 statistics on results.  SPECINDX is the spectral index
                 used with SMODEL.
   SETJY.........Task to enter source info into source (SU) table.
                 SPECINDX is the spectral index to be used with ZEROSP
                 and SPECURVE.
   SOUSP.........Fits SPECINDX and SPECURVE to the fluxes in an SU
                 table returning the values for input to BPASS.

EXPLAIN SECTION