On Saturday, December 17, 2016 at 10:10:42 AM UTC-5, wrote:
On Tuesday, December 13, 2016 at 1:09:29 PM UTC-8, Phillip Helbig (undress to reply) wrote:
In article ,
jeantate writes:

Maybe you've got this covered in starlight, but dust is a major
contributor in the IR;

It gets heated by normal stars, supernovae, AGN, etc. One shouldn't
count it twice.

Yes, dust glows in IR, but, I'm seeking sources of energy production.
There are no energy producing processes going on in dust. They just
absorb and re emit starlight, wavelength shifted to IR.

They absorb and re-emit light, whether from stars, SNe, AGN, ... They
are also heated by collisions with gas molecules, in dense GMCs; that
surely counts as 'energy production', right?

Collisions, yes, but that's so rare I can't imagine it's significant.

Maybe today, but back when galaxies were being formed they weren't rare
at all. How much of the FIR background we observe today is due to high-z
collisions?

SNIa and SNII are both significant, somewhat surprisingly given how rare
they are per galaxy. Especially SNII neutrino energy, that surprised
me.

Hmm ... then why haven't you included the CNB (cosmic neutrino
background)?

AGN emission is one I'm working on at the moment. I haven't found an
estimate for numbers of galaxies that go through the agn phase.

Every galaxy with a SMBH will have at least one "AGN phase", won't it?
And likely many more than one. And that's (almost?) all non-dwarf
galaxies, right?

Oh, and what's the energy source for the x-ray emitting IGM (due to its
high temperature) in (rich) clusters?