Host Galaxies of Dwarf AGN with Rubin Legacy Survey of Space Time and Euclid
Lead Research Organisation:
University of Southampton
Abstract
Feedback from actively accreting supermassive black holes (AGN) is known to play a fundamental role in shaping massive galaxies. In low-mass, "dwarf" galaxies, the impact of black holes has until recently been largely overlooked. However, new simulations and observations with the James Webb Space Telescope (JWST) suggest that a significant number of dwarf galaxies host active black holes, which may therefore be key to their evolution. This project aims to explore the co-evolution of black-holes and their host galaxies at low masses using new variability-based selection techniques for AGN identification. Variability selection is unearthing a previously unstudied population of accreting black holes at low-masses and will be transformed by the arrival of data from the Vera C. Rubin Observatory Legacy Survey of Space Time (LSST) from mid 2026 which will allow low-mass black holes to be routinely detected out to redshift 1.
Key Scientific Questions
This project will address several fundamental questions on the nature of the host galaxies of new variability selected AGN from Rubin-LSST:
What are the stellar masses and star formation rates of variability selected AGN? What fraction of variability selected AGN reside in dwarf galaxies?
Do dwarf galaxies follow the same relationships between black hole mass and galaxy mass as seen in massive galaxies?
Are galaxy mergers responsible for triggering black hole activity in these systems, or is secular evolution more important?
What is the incidence of off-nuclear 'wandering' black-holes and dual AGN in the dwarf regime?
Research Approach
To answer these questions, we will leverage state-of-the-art data from upcoming astronomical surveys. Rubin-LSST will provide unprecedented samples of variability selected black holes beyond the local Universe. Combining this with near infrared imaging from VISTA will enable constraints on their host stellar masses and star formation rates. We will also use high-resolution imaging from the Euclid space telescope to analyze the morphologies of the host galaxies and search for dual and off-nuclear AGN.
The project will focus on three main areas:
Measuring the stellar masses and star formation rates of dwarf galaxies hosting accreting black holes – We will use advanced image decomposition techniques combined with machine learning to separate AGN and host galaxy emission and constrain the stellar masses and star formation rates of variability selected AGN. We will therefore determine how many variability selected AGN reside in dwarf galaxies with M*<3x10^9M_0 and establish whether dwarf galaxies at z>0.1 follow local scaling relations between galaxy and black-hole mass.
Morphologies of dwarf AGN host galaxies – We will determine if dwarf AGN host galaxies contain bulges, disks, or evidence of past mergers, shedding light on how black holes and galaxies co-assemble at low masses.
Identifying rare black hole populations – We will search for “dual AGN” (two black holes in the same galaxy) and “wandering” black holes that have been displaced from their galaxy centers, testing theories of black-hole seed formation.
Why This Project Will Succeed
Our team has access to cutting-edge datasets and analysis tools, including expertise in the Rubin LSST image-processing pipelines. We are involved in major international collaborations such as Rubin-LSST and Euclid with significant leadership roles within LSST and LSST:UK, ensuring that our findings will be integrated with broader efforts in the field.
Key Scientific Questions
This project will address several fundamental questions on the nature of the host galaxies of new variability selected AGN from Rubin-LSST:
What are the stellar masses and star formation rates of variability selected AGN? What fraction of variability selected AGN reside in dwarf galaxies?
Do dwarf galaxies follow the same relationships between black hole mass and galaxy mass as seen in massive galaxies?
Are galaxy mergers responsible for triggering black hole activity in these systems, or is secular evolution more important?
What is the incidence of off-nuclear 'wandering' black-holes and dual AGN in the dwarf regime?
Research Approach
To answer these questions, we will leverage state-of-the-art data from upcoming astronomical surveys. Rubin-LSST will provide unprecedented samples of variability selected black holes beyond the local Universe. Combining this with near infrared imaging from VISTA will enable constraints on their host stellar masses and star formation rates. We will also use high-resolution imaging from the Euclid space telescope to analyze the morphologies of the host galaxies and search for dual and off-nuclear AGN.
The project will focus on three main areas:
Measuring the stellar masses and star formation rates of dwarf galaxies hosting accreting black holes – We will use advanced image decomposition techniques combined with machine learning to separate AGN and host galaxy emission and constrain the stellar masses and star formation rates of variability selected AGN. We will therefore determine how many variability selected AGN reside in dwarf galaxies with M*<3x10^9M_0 and establish whether dwarf galaxies at z>0.1 follow local scaling relations between galaxy and black-hole mass.
Morphologies of dwarf AGN host galaxies – We will determine if dwarf AGN host galaxies contain bulges, disks, or evidence of past mergers, shedding light on how black holes and galaxies co-assemble at low masses.
Identifying rare black hole populations – We will search for “dual AGN” (two black holes in the same galaxy) and “wandering” black holes that have been displaced from their galaxy centers, testing theories of black-hole seed formation.
Why This Project Will Succeed
Our team has access to cutting-edge datasets and analysis tools, including expertise in the Rubin LSST image-processing pipelines. We are involved in major international collaborations such as Rubin-LSST and Euclid with significant leadership roles within LSST and LSST:UK, ensuring that our findings will be integrated with broader efforts in the field.