Author here: this are my notes on what I mean to say in class, the website contain my whole course.
This particular lecture is still “in prep“, in fact the section "the problem" is just a bullet point and a figure. All other lectures are a bit more polished.
Unless I'm missing something - do the notes cover neutrino astronomy somewhere else? Aside from the general discussion on stellar evolution. Shame, because the detection of pre-optical neutrino emission from 1987A by Kamiokande (and others) was a fantastic theoretical confirmation. Essentially when the core collapses, the environment around the surroundings are optically opaque, but the neutrinos sail on through so you'd expect to see them before the photons.
I would recommend Telescope in the Ice as one of the best introductions to modern neutrino detectors - why and where they're built. Also provides a good insight into how a big collaboration is formed, funded and operates. I've worked for IceCube so I'm somewhat biased, but the book is great just for the history.
IceCube has an entire processing pathway (on ice) that is specifically designed to trigger on a supernova detection. One of the very few science results that would page us, and why uptime is absolutely critical to the experiment. On the one hand, we can't point the detector and we don't know where the signal will come from, so it's not predictable (and it's highly transient). On the other, becuase the burst happens shortly before the optical, we can use neutrinos to trigger optical observations as fast as possible - pretty much the whole observing community will drop what they're doing if a star blows up.
These are my notes for a course in stellar physics that I am teaching, the full set of lecture notes is here https://www.as.arizona.edu/~mrenzo/courses/lectures.html and includes some more on neutrino cooling in evolved stars, core collapse physics, and a guest lecture (also with notes that I am NOT the author of) on high energy neutrinos, but if you want to learn specifically about neutrino astrophysics this is certainly not the most comprehensive resource.
Re neutrinos, I would also mention KM3NET which looks for Cherenkov flashes in the Mediterranean sea used as a detector, which recently detected some extremely high energy neutrinos, e.g.:
> Essentially when the core collapses, the environment around the surroundings are optically opaque, but the neutrinos sail on through so you'd expect to see them before the photons.
Also, the source, the hot nascent neutron star, is optically thick to neutrinos, so it radiates them very fiercely. Almost all the energy of the collapse goes into neutrino radiation.
Hopefully an expert can chime in, but from what I've gathered we were fairly lucky to catch that one.
First off, it needs to happen when enough detectors are operational to get a good localization. Back then there were just three and all happened to be operational during the event. Just two won't cut it, as you can see from this[1] using just LIGO data versus this[2] which also includes VIRGO data for GW170817[3].
Next the detectors have a limited mass window they're sensitive to, with low frequencies (high mass) limited by seismic isolation and high frequencies (low mass) due to quantum effects. And the noise floor at peak sensitivity limits the maximum range to the objects.
Current sensitivity means we're at the edge of the binary-neutron star population, so we wouldn't expect to see many of those.
With more detectors coming online soon and existing ones getting further upgraded, presumably it'll not be such a rare event in the future.
A nice recent talk which touches on this was given at PIRSA here[4].
The problem is that the angular resolution is not all that great so it could've been a coincidence. With the number of observations we make and the relative frequency of supernovae anywhere, it's surprising that n isn't at least 2. Or 5.
Author here: this are my notes on what I mean to say in class, the website contain my whole course.
This particular lecture is still “in prep“, in fact the section "the problem" is just a bullet point and a figure. All other lectures are a bit more polished.
Unless I'm missing something - do the notes cover neutrino astronomy somewhere else? Aside from the general discussion on stellar evolution. Shame, because the detection of pre-optical neutrino emission from 1987A by Kamiokande (and others) was a fantastic theoretical confirmation. Essentially when the core collapses, the environment around the surroundings are optically opaque, but the neutrinos sail on through so you'd expect to see them before the photons.
https://ui.adsabs.harvard.edu/abs/1987ApJ...318L..63B/abstra...
I would recommend Telescope in the Ice as one of the best introductions to modern neutrino detectors - why and where they're built. Also provides a good insight into how a big collaboration is formed, funded and operates. I've worked for IceCube so I'm somewhat biased, but the book is great just for the history.
IceCube has an entire processing pathway (on ice) that is specifically designed to trigger on a supernova detection. One of the very few science results that would page us, and why uptime is absolutely critical to the experiment. On the one hand, we can't point the detector and we don't know where the signal will come from, so it's not predictable (and it's highly transient). On the other, becuase the burst happens shortly before the optical, we can use neutrinos to trigger optical observations as fast as possible - pretty much the whole observing community will drop what they're doing if a star blows up.
I believe we'd expect the whole flux through the detector to bump up above the background, at least at IceCube. PDF: https://iopscience.iop.org/article/10.1088/1742-6596/309/1/0...
These are my notes for a course in stellar physics that I am teaching, the full set of lecture notes is here https://www.as.arizona.edu/~mrenzo/courses/lectures.html and includes some more on neutrino cooling in evolved stars, core collapse physics, and a guest lecture (also with notes that I am NOT the author of) on high energy neutrinos, but if you want to learn specifically about neutrino astrophysics this is certainly not the most comprehensive resource.
Re neutrinos, I would also mention KM3NET which looks for Cherenkov flashes in the Mediterranean sea used as a detector, which recently detected some extremely high energy neutrinos, e.g.:
https://www.nature.com/articles/s41586-024-08543-1
> Essentially when the core collapses, the environment around the surroundings are optically opaque, but the neutrinos sail on through so you'd expect to see them before the photons.
Also, the source, the hot nascent neutron star, is optically thick to neutrinos, so it radiates them very fiercely. Almost all the energy of the collapse goes into neutrino radiation.
After so many observations why is multi messenger still n=1?
Hopefully an expert can chime in, but from what I've gathered we were fairly lucky to catch that one.
First off, it needs to happen when enough detectors are operational to get a good localization. Back then there were just three and all happened to be operational during the event. Just two won't cut it, as you can see from this[1] using just LIGO data versus this[2] which also includes VIRGO data for GW170817[3].
Next the detectors have a limited mass window they're sensitive to, with low frequencies (high mass) limited by seismic isolation and high frequencies (low mass) due to quantum effects. And the noise floor at peak sensitivity limits the maximum range to the objects.
Current sensitivity means we're at the edge of the binary-neutron star population, so we wouldn't expect to see many of those.
With more detectors coming online soon and existing ones getting further upgraded, presumably it'll not be such a rare event in the future.
A nice recent talk which touches on this was given at PIRSA here[4].
[1]: https://dcc.ligo.org/public/0146/G1701985/001/bayestar_no_vi...
[2]: https://dcc.ligo.org/public/0146/G1701985/001/bayestar.png
[3]: https://dcc.ligo.org/LIGO-P170817/public
[4]: https://pirsa.org/25030061
The problem is that the angular resolution is not all that great so it could've been a coincidence. With the number of observations we make and the relative frequency of supernovae anywhere, it's surprising that n isn't at least 2. Or 5.
Thank you
Figure 3 is really nice!
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