The Ultra-Low Frequency Universe

Introduction

The ULU project will explore the largest scales of our Universe, mapping one of the last uncharted observational windows of the cosmic electromagnetic spectrum: the ultra-low radio frequencies (10-100 MHz). Although these frequencies are crucial to unveil the nature and evolution of galaxy clusters, the complexity of such observations prevented their exploitation until now.

Methodology

Techniques I developed to analyse Low Frequency Array (LOFAR) data were able to overcome this limitation. With ULU, we will survey the northern sky, producing ultra-low frequency images that are 100 times more sensitive than the state-of-the-art.

Scientific Impact

The legacy of ULU will be long-lasting with a far-reaching scientific outcome, including:

• Galaxy evolution
• Ionospheric science
• Exoplanet habitability
• Detection of the first galaxies at cosmic dawn

Research Focus

Within the ULU project, I will combine the survey with my expertise on the study of galaxy clusters. My group will adopt an innovative approach based on unveiling the full picture of the cosmic ray (CR) life-cycle in the intracluster medium. This approach will effectively combine diverse topics historically studied independently, such as:

1. The growth of structures
2. AGN activity
3. Galaxy evolution

Exploring Cosmic Rays

While conventional radio frequencies are sensitive to emission generated by highly energetic CRs, with ULU we will explore the far larger domain of low-energy CRs that can be accelerated by still unexplored microphysical mechanisms. Furthermore, their emission can be observed over Gyr time scales, revealing the long-term actions and interactions of radio sources in cluster environments.

Objectives

With a full picture of the CR life-cycle, we will:

1. Unveil how cluster merger energy is deposited in the intracluster medium through shocks, turbulence, and other mechanisms.
2. Measure the long-term effect of AGN feedback up to the age of cluster formation.
3. Make a realistic attempt at the characterization of the WHIM properties and constrain the origin of cosmological magnetic fields.