Searching for the Origin of Neutrinos Coming from the Galactic Plane

• Grant number: 23/12705-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2024
• End date: December 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics - Elementary Particle Physics and Fields
• Principal Investigator: Aion da Escóssia Melo Viana
• Grantee: Guilherme Santana de Almeida
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 19/14893-3 - Extreme phenomena of the Galactic Center and indirect searches of dark matter with gamma rays, AP.JP

Abstract

The Milky Way emits a wide range of radiation spanning the entire electromagnetic spectrum, from radio waves to gamma rays. Through observations at various wavelengths, we gain valuable insights into the structure of our galaxy and pinpoint sources of the most high-energy photons. In the case of gamma rays with energies exceeding 1 giga-electronvolt (GeV), the Milky Way's plane becomes the most prominent feature visible in our skies. Most of this observed gamma-ray flux consists of photons generated by the decay of neutral pions, themselves produced by cosmic rays (high-energy charged particles) colliding with the interstellar medium within the Milky Way galaxy. In addition to neutral pions, these cosmic-ray interactions yield charged pions, and when these charged pions decay, they produce neutrinos. And neutrinos, even more so than gamma photons, have the unique characteristic of rarely interacting with other matter during their journey to Earth. Consequently, they offer direct insight into the locations and energies of cosmic-ray interactions. As both gamma rays and neutrinos emerge from the decay of pions, there should be, in principle a correlation between the known gamma-ray sources and neutrino sources. In 2013 IceCube neutrino collaboration detected for first time ever an isotropic neutrino flux coming from space which extends up to very high energies. However to establish the emitting objects and the exact mechanism involved is not an easy task and requires to collect a big quantity of data. Finally, after 10 years of operation, the Collaboration has released 7 year data for the full 86 string configuration, and published a paper related with these data looking for point-like sources. In 2023, an analysis of the same dataset identified a neutrino emission from the Galactic plane by comparing diffuse emission models to a background-only hypothesis. The signal was consistent with modeled diffuse emission from the Galactic plane, but could also arise from a population of unresolved point sources. In this project we propose to study a correlation analysis of neutrinos coming from the galactic plane and their possible connections with emitters, such as Supernova Remnants (SNR), Pulsar Wind Nebulae (PWN), Particle Accelerating Colliding-Wind Binaries, and others. The main objective of the proposed activity is to introduce the student to the context of research, by means of the study of non-thermal high-energy astrophysical phenomena and numerical calculations in astrophysics.