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L_Universe due to SNII Neutrinos = 322 * L_Universe?
In SLAC lecture at
https://www.youtube.com/watch?v=3DHiCRTUxgwPY Public Lecture | Supernovas: Gravity-powered Neutrino Bombs Alex Friedland comments that for a snII, the power emitted in neutrinos for about 10 seconds outshines all the L of stars in entire universe, at about time: 36:45. He states that the neutrino burst is 100x more powerful than the visible explosion, and that during the 10 seconds neutrinos are being emitted, the power is greater than visible emissions in all stars in the entire universe. He also mentions 10% of mass of collapsed core is converted to energy There are around 31E6 seconds per year. About 1 SN per galaxy per 100 years. Is this about right for SNII, especially in the past? And about 100E9 galaxies in visible universe. So that means about 1 billion SN per year in the now visible universe. But that means the Luminosity from neutrinos is L_neutrinos/Universe = L_universe * 10s/SN * 1SN / 100yrGal * 1yr/31E6s * 100E9Gal/Univ so, L_neutrinos from SNII explosions = 322 L_universe starlight Really? Is L from SNIA similarly large? |
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L_Universe due to SNII Neutrinos = 322 * L_Universe?
On Wednesday, December 14, 2016 at 1:57:51 AM UTC-5, wrote:
In SLAC lecture at https://www.youtube.com/watch?v=3DHiCRTUxgwPY Public Lecture | Supernovas: Gravity-powered Neutrino Bombs Alex Friedland comments that for a snII, the power emitted in neutrinos for about 10 seconds outshines all the L of stars in entire universe, at about time: 36:45. He states that the neutrino burst is 100x more powerful than the visible explosion, and that during the 10 seconds neutrinos are being emitted, the power is greater than visible emissions in all stars in the entire universe. He also mentions 10% of mass of collapsed core is converted to energy AFAIK, this is not news. Have you tried searching the relevant literature on core collapse SNe? There are around 31E6 seconds per year. About 1 SN per galaxy per 100 years. Is this about right for SNII, especially in the past? I doubt it. Core collapse SNe are exceedingly rare in early-type galaxies ("ellipticals") because there are no stars massive enough. Type Ia SNe however ... And about 100E9 galaxies in visible universe. So that means about 1 billion SN per year in the now visible universe. But that means the Luminosity from neutrinos is L_neutrinos/Universe = L_universe * 10s/SN * 1SN / 100yrGal * 1yr/31E6s * 100E9Gal/Univ so, L_neutrinos from SNII explosions = 322 L_universe starlight Really? No. Galaxies are not at all like electrons; they have a huge range of sizes, masses, and (most important) distributions of stars by mass. Is L from SNIA similarly large? Why not do some reading up on supernovae? The answers aren't all that hard to find :-) |
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L_Universe due to SNII Neutrinos = 322 * L_Universe?
On Wednesday, December 14, 2016 at 12:52:12 PM UTC-8,
wrote: [Moderator's note: Inappropriate comments deleted. -P.H.] I doubt it. Core collapse SNe are exceedingly rare in early-type galaxies ("ellipticals") because there are no stars massive enough. Type Ia SNe however ... This is not correct as far as I know. Today, in the modern universe, sure this is correct. But I was probing back to initial star formation. So, many of the stars that formed into the earliest galaxies came from star fields / formation regions, and within those were many SNII explosions. The reason we don't see SNII in elliptical galaxies today is just that they are (for the most part) no longer forming new stars After the dark ages, during the era of initial star formation, SNII were common and the largest stars were likely larger than today with extremely short lifetimes, helping explain why finding type III stars is so difficult to day. Early SNII polluted the gas of the universe with heavy elements. So the statement that early type galaxies don't host SNII is correct in the modern universe but not in the early universe when the first stars were born. AFAIK. rt |
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