On the Analysis of ParaAmmonia Observations
Abstract
The intensities and optical depths of the (1, 1), (2, 2), and (2, 1) inversion transitions of ammonia can be calculated quite accurately without solving the equations of statistical equilibrium. A twotemperature partition function suffices. The excitation of the Kladders can be approximated by using a temperature obtained from a twolevel model with the (2, 1) and (1, 1) levels. Distribution of populations between the ladders is described with the kinetic temperature. This enables one to compute the (1, 1) and (2, 1) inversion transition excitation temperatures and optical depths. To compute the (2, 2) brightness temperatures, the fractional population of the (2, 2) doublet is computed from the population of the (1, 1) doublet using the 'true rotation temperature,' which is calculated using a threelevel model with the (2, 1), (2, 2), and (1, 1) levels. In spite of some iterative steps, the calculation is quite fast.
 Publication:

The Astrophysical Journal
 Pub Date:
 October 1994
 DOI:
 10.1086/174679
 Bibcode:
 1994ApJ...433..712K
 Keywords:

 Ammonia;
 Approximation;
 Interstellar Matter;
 Mathematical Models;
 Molecular Excitation;
 Optical Transition;
 Temperature;
 Molecular Collisions;
 Partitions (Mathematics);
 Radio Astronomy;
 Radio Spectra;
 Astrophysics;
 ISM: MOLECULES;
 METHODS: DATA ANALYSIS;
 RADIO LINES: ISM