Project description
Tracing the source of intergalactic magnetic fields
Magnetic fields that persist throughout Space and spread far beyond the galaxies that created them represent a significant recent finding in cosmology. Their morphology is imprinted on the cascade of sub-atomic particles generated by gamma rays interacting with background radiation fields. The EU-funded GammaRayCascades project will combine observation data from air Cherenkov telescopes and the Fermi Large Area Telescope with precise model predictions of the cascade. Their aim is to detect the cascade signal and the intergalactic magnetic field. Measuring intergalactic magnetic fields will provide crucial information about how large-scale structures form, how the Universe evolves, and how charged cosmic rays and electromagnetic waves propagate through intergalactic space.
Objective
The existence of an intergalactic magnetic field (IGMF) remains elusive and only upper limits on its strength are known from limits on the rotation of polarization angles of radio waves. Its measurement would provide crucial information about large scale structure formation, since the IGMF is thought to act as a seed field for magnetic fields in galaxies and galaxy clusters, how the Universe evolved, and how charged cosmic rays and electromagnetic waves propagate through intergalactic space.
Here, I propose a new search for IGMF signatures using observations of a high-energy gamma-ray cascades from distant galaxies. Gamma rays interact with background radiation fields to produce electron-positron pairs. These pairs up-scatter cosmic-microwave photons to gamma-ray energies, initiating the cascade. The IGMF morphology is imprinted on the cascade through a deflection of the pairs in the IGMF. A novel combination of observations with imaging air Cherenkov telescopes and the Fermi Large Area Telescope, using both spectral and spatial information, combined with precise model predictions of the cascade, promise an unprecedented sensitivity for detection of the cascade signal and the IGMF. Strong constraints on the IGMF strength will be possible if no cascade is detected.
Furthermore, I will also search for a gamma-ray and neutrino signal from cascades initiated by cosmic rays from active galaxies. This will yield an independent probe of the IGMF and, additionally, constraints on the cosmic-ray acceleration power of such galaxies. As part of this work, I will also make predictions how the future Cherenkov Telescope Array (CTA) can further improve the detection of or constraints on the IGMF and the cosmic-ray acceleration power of active galaxies. This will result in an optimized observation strategy for the extragalactic survey and the blazar monitoring program, which are both planned with CTA.
Fields of science
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
91054 Erlangen
Germany