From: hpollins@webaplomb.com (Harvey)

Newsgroups: sci.physics.plasma

Subject: Stromgren Radius

Date: 2 Jan 2005 16:07:33 -0800

Organization: http://groups.google.com

Hi All

Can someone please help.

I am trying to work out the Stromgren Radius for an active Galaxy that

is acting as a source of ionising photons. The nucleus of the Galaxy

has an ionising Luminosity L of 10^37 Watts. The mean energy of each

emmitted UV photon is 50eV. The nucleus of the Galaxy is surrounded by

an interstellar medium of pure hydrogen. The number density n(r)

varies with radial distance (r) from nucleus as n(r)=10^8(100parsecs /

r) per cubic metre. The recombination coefficient (alpha) has a value

of 10^-19 per cubic metre per sec.

The main problem is how to establish a value for n since it is a

function of radius - which is turn is a function of the Stromgren

radius - which is what I am trying to establish!!!!!!!!!!!!!!

Please can someone help.

All comments welcome,

Thank you

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