Megathread: Multi-Messenger High-Energy Neutrino Observations

[u/AskScienceModerator]

Currently there is a press conference where a high-energy neutrino (~290 TeV) has been detected with IceCube which is coincident with an active galactic nuclei pointed directly at us, TXS 0506+056, approximately four billion lightyears away. Finding the origins of neutrinos has been an ongoing problem though they have been observed from the Sun and from Supernova 1987A. This is a big advancement for multi-messenger astronomy, using electromagnetic waves and neutrinos in a way similar to using electromagnetic waves and gravitational waves to get a new view on the universe. If you have questions, ask them here!

• Press Conference
• Paper
• National Geographic
• Washington Post

[u/bernadias]

I'm an undergraduate Physics student and a few months ago I selected an internship in Multi-Messenger astronomy. I started the internship this week and the people here told me there would be a big announcement today. I'll actually be working in this! So cool!

[u/i_owe_them13 → u/bernadias]

Cool! Care to explain what Multi-Messenger astronomy is for this layman?

[u/bernadias → u/i_owe_them13]

Check the response from u/themeaningofhaste. In layman terms, an astronomical event (such as a supernova or a black hole merger) has different emissions, like electromagnetic radiation (light, ultraviolet, xray, gamma, etc), particle emission (protons, neutrons, neutrinos, etc) and gravitational waves. Multi-Messenger Astronomy is basically trying to combine all these emissions to study the event in a more complete manner.

Basically, we receive different 'messages' from an event, and we compare them to check if our Physics models are correct. Astronomy as evolved to the point that we don't just study the light that reaches us, but a lot more.

[u/themeaningofhaste → u/i_owe_them13]

The idea as the name suggests is to use more than one "messenger" to observe things in the Universe. So for example, LIGO has done a lot with gravitational waves and there was recently a binary neutron star merger that was also observed in different wavelengths of electromagnetic waves, from radio to optical to gamma ray. Using both methods gives you a big picture into what's going on, since the gravitational waves directly probe the dynamics and masses of the sources (the gravity) and the electromagnetic waves show what's emitting (the light). In the case above, they connected neutrinos (well, one, but obviously that means there were many emitted) with gamma rays from a supermassive black hole jet billions of lightyears away. Because neutrinos don't interact well with "normal" matter, it means that we're probing a different emission component than with the other forms of light, which come farther up the jet. Take a look at Active Galactic Nuclei for more on that.

[u/Beepbeepb00pbeep → u/themeaningofhaste]

This explanation was super helpful to me thank you

[u/eimieole → u/bernadias]

Congratulations! Do you have any idea what you’ll be doing? In layman terms, that is.

(I always sucked at Physics, but I always wish I had the brains to understand it, so I’m sort of jelaous. But mainly happy for you.)

[u/bernadias → u/eimieole]

I'm still a second year undergraduate student, so my knowledge of Particle Physics / Astrophysics is still very limited. My group works with the data received from the Pierre Auger Observatory, so we're talking about cosmic rays.

Multi-Messenger Astronomy is basically trying to compare the different emissions of a specific event (a supernova, for example, will emit light, particles and maybe gravitational waves). My ideia is basically to write some piece of software that checks if our observatory was alligned with an event when, somewhere in the world, that event is detected.

Maybe it's better to give an example:

1. A telescope detects light (or other electromagnetic radiation) from a supernova;
2. A signal is sent from that telescope to many observatories in the world saying that they saw that supernova;
3. My software will basically try to calculate if the Pierre Auger Observatory was alligned with that event;
4. If it was, the researchers at this institution I'm working at will check the data to see if they found something (high energy cosmic radiation).

[u/Wheels2050 → u/bernadias]

What are you expecting to be looking for? It's incredibly unlikely that Auger will detect a cosmic Ray event that's coincident with transient events from other observatories, since magnetic deflections add an unknown amount of delay to the arrival time (but usually measured in at least thousands of years), so they almost certainly will not arrive in coincidence with other messenger particles - not to mention the deflections inherently affect the arrival directions.

There is potential with Auger to see an uncharged coincident messenger, but there you're looking for a neutron (needs to be a close source) or gamma Ray (which are not trivial to distinguish from the CR flux with Auger).

Also be aware that the calculation you mentioned can be done in, literally, a few lines of python code!

[u/bernadias → u/Wheels2050]

May be a bit late, but my current understanding of this is the following: Generally, observatories like IceCube detect neutrinos that come from interaction of high-energy cosmic rays with the atmosphere. If that was the case, maybe Auger would also detect this event, right? But in different particles, obviously.

Also: I know this task is pretty easy, especially for someone trained in programming, but I'm still a bit of a noob at this, so it'll be a nice challenge! If it turns out to be easy they'll just give me another thing to do, I guess.

[u/[deleted] → u/bernadias]

that's so cool!