Yes, exactly. "No hope squared" is an excellent way of putting it!
Core collapse supernovae emit copious amounts of neutrinos, primarily from neutrino cooling after the hot neutron star is born. Type Ia, in contrast, work by rapid nuclear fusion of carbon. To say that the process emits no neutrinos would be incorrect... but they aren't coming out in massive quantity.
For a core collapse supernova, we really are limited to our own galaxy and its satellites for seeing supernova neutrinos. Our "canonical supernova" is near the center of the galaxy, where star density is high. That is a distance of 10 kpc; a core collapse supernova there would give us about 10,000 events in Super-Kamiokande.
Jump now to our next nearest [non-satellite] galaxy, Andromeda. At a distance of about 800 kpc, the inverse square spread of the neutrinos reduces the flux by a factor of 6400 from our canonical supernova... meaning that only one or two events will be seen. Which will not be distinguishable from background, I'm afraid. Of course, at a distance of about 7 Mpc, the Pinwheel Galaxy supernova would not get even a signal interacting neutrino event to our detector... even if it were of the core collapse type!
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Date: 2011-09-10 08:26 am (UTC)Core collapse supernovae emit copious amounts of neutrinos, primarily from neutrino cooling after the hot neutron star is born. Type Ia, in contrast, work by rapid nuclear fusion of carbon. To say that the process emits no neutrinos would be incorrect... but they aren't coming out in massive quantity.
For a core collapse supernova, we really are limited to our own galaxy and its satellites for seeing supernova neutrinos. Our "canonical supernova" is near the center of the galaxy, where star density is high. That is a distance of 10 kpc; a core collapse supernova there would give us about 10,000 events in Super-Kamiokande.
Jump now to our next nearest [non-satellite] galaxy, Andromeda. At a distance of about 800 kpc, the inverse square spread of the neutrinos reduces the flux by a factor of 6400 from our canonical supernova... meaning that only one or two events will be seen. Which will not be distinguishable from background, I'm afraid. Of course, at a distance of about 7 Mpc, the Pinwheel Galaxy supernova would not get even a signal interacting neutrino event to our detector... even if it were of the core collapse type!