# olnon

Computes a free-free spectrum based on Olnon (1975) models.

### Usage:

```import olnon
olnon.olnon(Te, diameter, ne, Dkpc, filename='olnon.dat', doplot=False,
freqs=[], ylimits=[], model='truncatedPowerLaw', computeFWHM=False)
```
Inputs:
• Te: electron temperature in K
• diameter = diameter in AU of the central region of constant density
• ne = central density
• Dkpc = distance in kpc
• filename = the output ASCII file containing the spectrum
• doplot: create a pylab plot
• freqs: the grid of frequencies to calculate (default is 1-1000 GHz)
• ylimits: y-axis limits of the resulting plot
• model: 'cylinder', 'uniformSphere', 'gaussian', 'powerLaw', or 'truncatedPowerLaw' (the latter two use r^-2)
Returns:
1. ) array of frequencies in GHz
2. ) array of flux densities in Jy
3. ) the expected FWHM in AU (i.e. diameter containing half the flux) only relevant if computeFWHM==True

### Examples:

```CASA <26>: freq, flux, fwhm = olnon.olnon(10000, 1000, 1e6, 1.3, computeFWHM=True)
Total flux density = 8.778397
radius of half flux = 1.226488 = 0.002973 pc.  FWHP = 0.943452 arcsec = 1226.487832 AU
```
The following example shows how to generate Figure 3 from Olnon, where:
```CASA <27>: a=olnon.olnon(10000, 1000, 1e6, 1.3, doplot=True, model='all')
Wrote fnu_vs_nu.png
```
Color key:
• black=Model I = uniform cylinder
• blue = Model II = uniform sphere
• green = Model III = Gaussian
• red = Model IV = power law (r^-2)
• orange = Modle V = truncated power law (r^-2)
-- ToddHunter - 2015-12-04

Topic attachments
I Attachment Action Size Date Who Comment
png fnu_vs_nu.png manage 32 K 2015-12-04 - 14:26 ToddHunter Reproduction of Figure 3 in Olnon 1975
This topic: ALMA > ToddTools > Olnon
Topic revision: 2015-12-04, ToddHunter
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