The first detection of high-energy neutrinos in 2013 by IceCube opened a new window to the Universe. High-energy processes induced by cosmic rays can now be observed through neutrinos as products of hadronic interactions. First evidence of a blazar (TXS0506+056), a Seyfert-starburst composite (NGC1068), and the Milky Way show that we are moving toward astronomy with neutrinos. Nevertheless, the pointing precision of neutrino telescopes is limited to ~0.1°. Thus, the interpretation of the observed signal is always in need of high-precision measurements at electromagnetic wavelengths. In particular, radio and sub-mm astronomy are well-suited to help understand the origin of cosmic rays for two reasons:
(1) Synchrotron radiation at radio wavelengths reveals the acceleration of electrons. As it is likely that hadrons are accelerated in the same places, the emission even traces hadronic emission and neutrinos can arise from the same direction when the interaction with the gas or photon fields happens close to the acceleration site.
(2) Radio detection provides extremely good resolution and can pinpoint acceleration regions (see above), but also places of enhanced ionization (via the detection of molecular lines), dense gas, etc. via precision measurements of the molecular abundance in the medium.
Complementing optical detection, techniques for radio detection of high-energy neutrinos are currently being explored. These techniques exploit the fact that neutrino induced particle showers in ice generate detectable radio signals through the Askaryan effect.
The Nordic countries have a long history in both radio and neutrino astronomy. This puts them into a unique position to move forward and bring together the two branches of astrophysics. This workshop is the first to bring together the communities of the Nordic countries, their neighbors and everybody interested.
The two central scientific goals of the workshop are:
1) Enhancing the communication between the radio and neutrino communities concerning the identification and interpretation of the neutrino signatures with high-precision radio astronomy
2) Joining forces in R&D efforts in developing radio techniques for neutrino and radio astronomy.
