2021/07/30 by S. I. Stathopoulos, Μαρία Πετροπούλου, Stathopoulos, Stamatios I. +9
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Neutrino Physics Research
paper · doi:10.48550/arxiv.2107.14632
openalex publication_date 2021/07/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Blazars are the most extreme subclass of active galactic nuclei with relativistic jets emerging from a super-massive black hole and forming a small angle with respect to our line of sight. Blazars are also known to be related to flaring activity as they exhibit large flux variations over a wide range of frequency and on multiple timescales, ranging from a few minutes to several months. The detection of a high-energy neutrino from the flaring blazar TXS 0506+056 and the subsequent discovery of a neutrino excess from the same direction have naturally strengthened the hypothesis that blazars are cosmic neutrino sources. While neutrino production during gamma-ray flares has been widely discussed, the neutrino yield of X-ray flares has received less attention. Motivated by a theoretical scenario where high energy neutrinos are produced by energetic protons interacting with their own X-ray synchrotron radiation, we make neutrino predictions over a sample of a sample of X-ray blazars. This sample consists of all blazars observed with the X-ray Telescope (XRT) on board Swift more than 50 times from November 2004 to November 2020. The statistical identification of a flaring state is done using the Bayesian Block algorithm to the 1 keV XRT light curves of frequently observed blazars. We categorize flaring states into classes based on their variation from the time-average value of the data points. During each flaring state, we compute the expected muon plus anti-muon neutrino events as well as the total signal for each source using the point-source effective area of Icecube for different operational seasons. We find that the median of the total neutrino number (in logarithm) from flares with duration <30 d is N(\rm tot)νμ+νμ ∼ 0.02.