How to use the Bremsstrahlung flux to analyse a medium?

[mjda]

Homework Statement

Consider an HII region at a distance of 400 pc which is observed to emit thermal Bremsstrahlung across a wide range of radio wavelengths.

Independent analysis of emission lines suggests that the characteristic electron density and temperature of the H II region are 10^9 m^−3 and 10,000 K, respectively.

If the wavelength-integrated Bremsstrahlung flux at Earth is 3.1 x 10^−7 J / m2 / s, how can we estimate the radius of the HII region?

Relevant Equations

Where we can use:

[The Bremsstrahlung energy emitted in 1 s from 1 m^3 of a proton-electron plasma with a particle density of 1 m^−3 and temperature of 10^6 K is 1.4 x 10^−37 J, and 1pc = 3.086 x 10^16 m]

I don't know where to even begin?

 

[berkeman]

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