A-PLUS:
AGN POPULATIONS IN LARGE UNIFIED Surveys 

Welcome to the homepage of the A-PLUS collaboration!

We are a global team of radio and multiwavelength astronomers combining our expertise to build towards a holistic understanding of the role of supermassive black holes in our Universe. Together, we set up research projects, propose for new observations/surveys, publish results and reviews, and organize workshops and conferences. 

Understanding how galaxies grow and evolve

Most galaxies in the Universe are relatively quiet, but a small number host extremely energetic regions at their centres known as active galactic nuclei (AGNs). In some cases, these AGNs produce powerful radio emission, and these “radio AGNs” can have a big impact on their surroundings. They can influence how galaxies grow, how matter is distributed across space, and this in turn affects how their supermassive black holes evolve over time.

Despite their importance, our view of radio AGNs has been incomplete. Until recently, most detailed radio surveys of the sky focused on the northern hemisphere, leaving large parts of the southern sky less explored. This is now changing thanks to new, cutting-edge telescopes such as the Square Kilometre Array Observatory (SKAO) and its precursor facilities. Our collaboration aims to take advantage of this new opportunity. We are carrying out an ambitious research programme to study large numbers of radio AGNs in unprecedented detail. By analysing data from major radio surveys, including LOFAR, ASKAP, MeerKAT, the VLA and the MWA, we will build a clearer picture of how these objects behave and how they shape the Universe around them.

To get the fullest possible understanding, we will also combine radio observations with data across the entire electromagnetic spectrum, from visible light to gamma rays. This multi-wavelength approach allows us to connect what we see in radio waves with other properties of galaxies, such as their stars, gas, and high-energy activity. By bringing all of this information together, our goal is to better understand how galaxies and large-scale structures have formed and evolved over billions of years.

Main goals

Our key science goals include:

1. Understanding AGN-host galaxy properties through population studies, morphology and clustering.

2. Understanding the star formation history of the Universe and their connection with the spatial distribution of AGN activity.

3. Understanding the AGN feedback cycle and its role in structure formation and black hole growth.

4. Understanding the role of the environment on the observational properties of AGNs as seen today in the observable Universe.

5. Understanding the role and nature of cosmic magnetism in AGN activity.