redshifter.sh
Updated: Aug02,2020

Given a radial velocity (km/sec) and a list of restframe wavelength and feature names, compile a list of the redshifted wavelengths we would observe in a source at this velocity.

 
% redshifter.sh --help 

usage: redshifter.sh lines.1 29800.0 [-v] [-h]
arg1 - input file listing:  Wave_rest, Feature_Name
arg2 - radial velocity in km/s
Additional options:
     -v = print verbose comments and run in debug mode
     -h = just show usage message

 
Below I show a simple example of using this code to make the table file containing the redshifted values. The restframe wavelengths in the file spec.1 below can be quickly generated with the routine speclines.sh.
 
A simple example:

% cat spec.1 
  4101.740  H_delta        
  4340.470  H_gamma        
  4861.330  H_beta_L       

% redshifter.sh spec.1 10072.0  
Enter flux level (0.6): 0.4 

% cat redshifter.parlab 
wobs     Observed Wavelength (angstroms)
wrest    Rest Wavelength (angstroms)
flux     flux level
fname    Feature name
vobs      Radial Velocity (km/s)

% cat  redshifter.table 
   Wave_obs     Wave_rest          flux      Feautre            Vobs(km/s)
# data
    4239.450      4101.740         0.400     H_delta             10072.0
    4486.194      4340.470         0.400     H_gamma             10072.0
    5024.542      4861.330         0.400     H_beta_L            10072.0

The flux value is simply a place holder that aids in running, for instance, a routine that will mark features in a plotted spectrum. It is worth noting that the inverse routine for computing a radial velosity is redshift.




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