synth_spect.py

Python routine that generates a synthetic sub-mm/mm rotational spectrum from selected species using the CDMS/JPL databases and, optionally, compares it with an observed spectrum.

This python script reads online spectroscopic data through the JPL and CDMS databases. The synth_spect.py routine needs 2 to 3 input ASCII files: 1) input.in for the list of input parameters; 2) the file listing the properties of molecules needed to generate the synthetic spectrum; 3) optionally, the file describing the observed spectrum.

input.in

The input parameters needed by synth_spect.py are the following:

• choice_obs: 'yes' or 'no'. Whether or not you want to compare your synthetic spectrum with an observed one. If 'yes' is chosen, the min and max frequencies of the spectrum will match the observed spectrum.
• choice_data: 'local' or 'online'. Where to look for spectroscopic data. If 'online' is chosen, the routine will read and save the spectroscopic data into the 'data' folder. If 'local' is chosen, the routine assumes that all spectroscopic files have been previously downloaded.
• filemod: Name of the input model file.
• fileobs: Name of the input observed file.
• choice_y: Unit of intensity value ('Tpeak' for K, 'Fpeak' for mJy).
• prefix: Prefix of output files.
• beamsize: Beam size [arcsec].
• choice_tau: Include opacity in the calculations (yes or no).
• numin: Minimum frequency [GHz].
• numax: Maximum frequency [GHz].
• dnu: Spectral resolution [MHz].
• Vmin: Minimal value for selected transitions (K or mJy depending on choice_y).
• rms: rms noise of synthetic spectrum (K or mJy depending on choice_y).
• choice_plot: Output for the plot: 1) pdf, 2) python window.

modeled spectrum file

The modeled spectrum file contains the list of species to include in the synthetic spectrum together with their properties:

• total column density Ntot
• excitation temperature Tex
• source size ss
• offset velocity relative to the source velocity v_off
• the FWHM width of transitions width
• the spectroscopic database (jpl or cdms)
• vibrational correction factor
• reference (optional) of the properties

Please respect the number of characters as specified in the template. Lines starting with a ! or a # will be considered as comments. The file ends with a *.

observed spectrum file

The observed spectrum file is a 2-column ASCII file giving the frequency (in MHz) in the 1st column and the intensity in the 2nd one, with the unit depending on choice_y specified in input.in.

How to run the script

Install python3 and the usual packages numpy, pandas, matplotlib, and scipy. Once python3 is install, type:

python3 synth_spect.py