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#1
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Redshift when CBR energy density = energy density of all other radiation
I'm working to assemble a table / graph for the Luminosity of the
universe as a function of age of the universe. I think these are the only sources of consequence (did I miss anything important that I should include?): 1) CBR 2) Starlight (galaxies) 3) SN's 4) Active Galaxy nuclei Thanks, rt |
#2
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Redshift when CBR energy density = energy density of all other radiation
On Sunday, December 11, 2016 at 4:35:21 AM UTC-5, wrote:
: I'm working to assemble a table / graph for the Luminosity of the universe as a function of age of the universe. I think these are the only sources of consequence (did I miss anything important that I should include?): 1) CBR 2) Starlight (galaxies) 3) SN's 4) Active Galaxy nuclei Thanks, rt Maybe you've got this covered in starlight, but dust is a major contributor in the IR; too, the IGM in rich clusters at least is a major emitter in the x-ray region (this is certainly not covered in your four categories). Also, as you are aiming for luminosity, I assume you are (or intend to) integrate over all (electromagnetic) wavelengths; are you? |
#3
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Redshift when CBR energy density = energy density of all other radiation
In article ,
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. too, the IGM in rich clusters at least is a major emitter in the x-ray region (this is certainly not covered in your four categories). Good point. AFAIK, it is not heated appreciably by any of the other sources mentioned. |
#4
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Redshift when CBR energy density = energy density of all other radiation
On Sunday, December 11, 2016 at 4:35:21 AM UTC-5, wrote=
: I'm working to assemble a table / graph for the Luminosity of the universe as a function of age of the universe. I think these are the only sources of consequence (did I miss anything important that I should include?): 1) CBR 2) Starlight (galaxies) 3) SN's 4) Active Galaxy nuclei Thanks, rt One more, in addition to the hot IGM (a source of x-rays): galaxy-galaxy interactions, e.g. collisions, flybys, mergers. Especially interactions of (cold) gas-rich galaxies. These can, and do, trigger star-formation (sometimes spectacularly so), SNs, and can also fire up (often restart) AGNs. However, collisions of gas clouds can heat the gas (and its dust), so generating a lot of IR. PH is right, of course, to point out that dust is generally/often heated by starlight, SNe, etc ... but not always. Oh, and star-formation produces lots of photons, not all of them from stars ... |
#5
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Redshift when CBR energy density = energy density of all other radiation
On Tuesday, December 13, 2016 at 1:09:29 PM UTC-8, Phillip Helbig (undress to reply) wrote:
In article , 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. Collisions, yes, but that's so rare I can't imagine it's significant. SNIa and SNII are both significant, somewhat surprisingly given how rare they are per galaxy. Especially SNII neutrino energy, that surprised me. 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. rt |
#6
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Redshift when CBR energy density = energy density of all other radiation
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? |
#7
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Redshift when CBR energy density = energy density of all other radiation
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#8
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Redshift when CBR energy density = energy density of all other radiation
Hmm ... then why haven't you included the CNB (cosmic neutrino background)? As mentioned in other posts, Ross wants the amount of electromagnetic energy produced as a function of time. So, obviously, emission by anything which has been heated by electromagnetic radiation shouldn't be= counted, since that would be counting the corresponding energy twice. Also, neutrinos can be ignored since a negligible fraction of their energy is converted to electromagnetic radiation. Yes, exactly on target. If dust is heated by EM from stars where fusion was the originator of the energy conversion, then I would need to subtract off the energy that was absorbed, and add back in the energy radiated in IR. But those (in steady state) are the same values, though red shifted wavelengths. So, no point bothering with absorption and re emission. [Moderator's note: Right. I read yesterday that about half of stellar energy is absorbed and re-radiated in the infrared. -P.H.] As for Cosmic neutrino background, if I understand right, those were produced during the big bang, prior to launch of CMB. I'm counting energy production AFTER the CMB was launched. So we go through dark ages, no energy production, then star formation and the tale begins and I begin tracking energy production. Now **IF** there were significant energy transfer from cosmic neutrinos into the gas and stars, now and or back in early universe, then I'd need to count that energy. I've assumed that is negligible, as seems to be confirmed in comment above. However, I do have a red flag in my brain since so much energy in SNII comes out in neutrinos. The energy in those supernovae is in part, energy from neutrinos colliding with the matter of the star, so that would count. Thugh I'm adding SNII energy which I believe already includes that quantity. That said, this thread has wandered off topic me thinks. rt |
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