ANTARES search for neutrinos from M77/NGC 1068 after IceCube results

[Published  March 22nd, 2019]


The analysis of 10 years of IceCube data (IC40, IC59, IC79, IC86-1, ICII-ICVII) has recently been unblinded, unifying the muon diffuse and point source streams, and presented this week at the XVIII International Workshop on Neutrino Telescopes (Neutel 2019). The results are consistent with background, both for the Northern and Southern hemispheres. A list of 110 targets, motivated by gamma-ray observations, was also unblinded. The hottest source was found to be M77 (RA 40.667, Dec -0.0069) some 0.3 away from the all-sky hot spot, with a significance of 2.9σ (post-trial). At a distance of 14 Mpc, M77, also known as NGC 1068, is one of the closest Seyfert galaxies with a supermassive black hole in its core with misaligned jet.

Using data taken between 2007 and 2017, ANTARES has searched for high energy neutrinos in the direction of M77. The results, shown in the figure below, are consistent with background, yielding an upper limit on a possible E-2 neutrino spectrum of 8.7x10-9 GeV/cm2/s, with similar values for indices between 1.6 and 2.7.
Distribution of ANTARES events in the (RA, DEC) coordinates around the position of M77. The inner (outer) green line depicts the one (five) degree distance from the position source location, indicated as a gray star. The red point denotes a shower-like event, whereas the blue points indicate track-like events. The dashed circles around the events indicate the angular error estimate. Different shades of red and blue correspond to the values assumed by the energy estimators, the right legend shows the color scales. The number of hits is used for shower-like events and a parameter ρ for track-like events.



More details on the Neutel Website, in particular the talks from Francis Halzen and Tessa Carver.