Confirming the basic assumption and usage of PyNeb

[Yao-Lun Yang]

Dear all,

I typically deal with molecular gas in sub-mm/mm wavelength, so I'm a bit new to this field.  We are trying to use PyNeb to better understand the [OIII] 52 um line we detected in our observations.  The basic idea is to estimate the oxygen column density or mass given some assumptions of the ionized gas, such as n_e and T_e, following the formulae in Carniani+2015.  I want to confirm my understanding that, for the emissivity, PyNeb is calculating based on n_e and T_e only, by solving for population.  And the emissivity is per unit volume of n_e and unit volume of oxygen ion.  In other words, to derive the oxygen mass or even the total ionized gas mass, we need to make assumptions on the oxygen abundance and perhaps the ionization fraction.  Is that the correct understanding of the usage of PyNeb?  Thanks.

Best,

Yao-Lun

[Christophe Morisset]

Hi Yao-Lun,

Yes, you describe very well what PyNeb is actually doing.

Best saludos,

Christophe

[Yao-Lun Yang]

Thanks for confirming!

Best,

Yao-Lun