NEUTRINO 170922: the IceCube event

THE BLAZAR IN THE SKY. Astroparticle physics studies particles (messengers) coming to us from the Universe. When we come closer to this subject we start building a lot of bridges trying to connect the Universe with physics laws, mathematical models and experimental results. However, sometimes we forget to establish the most natural connection with the Universe: the sky naked eye observation.

Recently a "game changer" observation was done by IceCube, the South Pole Neutrino Observatory. A high energy neutrino (IceCube 170922) was detected, his arrival direction pointing with great precision to a super massive black hole in the BLAZAR TXS-0506+056. This experimental evidence led to the identification of blazar TXS 0506+056 as the FIRST likely source of high-energy cosmic rays.

We will discuss about this later. Now we would like to focus again on the observation of the sky, since, from the Northern hemisphere and in winter time, is very simple to observe the position in the sky of this amazing astrophysical source. The blazar is too far and to faint to be visible, but we can look at stars, find the position of the object and imagine what is hidden down there: a super massive black hole emitting twin jets of light and elementary particles along the axis of the black hole's rotation. Blazars have an extra feature: the jets are oriented toward us!

A couple of things more. 1. if you zoom in the picture taken with the camera at the point indicated by the orange arrow you will see that the camera sensors show a faint nebulosity glowing around a light spot: it is the wonderful Orion Nebula (M42). 2. M42 can be resolved with common binoculars.