Project description
Determining particle composition of relativistic jets
Relativistic jets from supermassive black holes are highly energetic phenomena that play a crucial role in galaxy evolution. Their composition (electron-positron pairs, electron-proton plasma, or a mixture) affects their power and emissions, with hadronic jets potentially serving as sources of the highest-energy cosmic rays. Circular polarisation is the only reliable method for determining their composition. The ERC-funded PARTICLES project will conduct high-cadence, multifrequency radio observations of relativistic jets, measuring total intensity, linear polarisation, and circular polarisation to clarify their particle makeup. It will also employ very long baseline interferometry to link light curves with the jets’ spatial structures. The project aims to determine the precise particle composition of these jets.
Objective
Relativistic jets launched by supermassive black holes are the most extreme and energetic persistent phenomena in the Universe. They are capable of accelerating particles to energies inaccessible by particle accelerators on Earth, and deposit enormous amount of energy in their surroundings during their lifetime. They are believed to have a significant impact on galaxy evolution via feedback mechanisms. Yet, despite decades of studies, one of the most fundamental properties, the composition of these jets is still unknown. The jets can consist of either electron-positron pairs, electron-proton plasma where also protons are present and accelerated, or an admixture of the two. The composition affects the power of the jet and the presence or lack of hadrons is a crucial ingredient in modelling the multi-wavelength and multi-messenger emission of these jets. If the jets are hadronic, they are likely the origin of the highest energy cosmic rays.
Circular polarization is the only direct way to determine the particle composition of jets, and we have designed a project that will overcome limitations of previous programs to finally resolve the particle composition of relativistic jets. Previously, this has only been attempted on individual objects at low radio frequencies, or using single-frequency data lacking the required discriminating power. PARTICLES will deliver the first multifrequency-radio high-cadence observations of relativistic jets in total intensity, linear, and circular polarization for a sample of objects. In parallel, we will conduct very long baseline interferometry observations to connect our light curves with the spatially resolved structures in the jets. This unprecedented dataset will be combined with radiative transfer simulations, crucial for modelling the origin of circular polarization. These advances will enable us to answer one of the most central questions related to relativistic jets, what is their particle composition?
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
This project's classification has been human-validated.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques. See: The European Science Vocabulary.
This project's classification has been human-validated.
Keywords
Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Programme(s)
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
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HORIZON.1.1 - European Research Council (ERC)
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Topic(s)
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Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
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Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
HORIZON-ERC - HORIZON ERC Grants
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Call for proposal
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Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
(opens in new window) ERC-2024-COG
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02150 Espoo
Finland
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