Letters of Intent received in 2022

LoI 2024-2191
All-inclusive AGN

Date: 5 August 2024 to 16 August 2024
Category: GA Symposium
Location: Cape Town, South Africa
Contact: Sarah / Sthabile White / Kolwa (sarahwhite.astro@gmail.com)
Coordinating division: Division J Galaxies and Cosmology
Other divisions: Division B Facilities, Technologies and Data Science
Division C Education, Outreach and Heritage
Division D High Energy Phenomena and Fundamental Physics
Co-Chairs of SOC: Dr Sthabile Kolwa (University of Johannesburg)
Dr Sarah White (Rhodes University)
Chair of LOC: None (None)



- Co-evolution of active galactic nuclei (AGN) and their host galaxies
- Multiwavelength AGN studies and future observing facilities
- Simulations of AGN, host galaxies and their gas environments
- Time-domain studies of AGN (e.g. reverberation mapping)
- Multimessenger astrophysics connected to AGN (e.g. gravitational waves, neutrinos)
- AGN classification and unification models
- Mechanical and radiative AGN feedback mechanisms
- The intergalactic and circumgalactic medium (IGM/CGM) of AGN host galaxies
- Star formation and molecular gas in AGN host galaxies
- The evolution of AGN at high redshift



Active galactic nuclei (AGN) are a key research topic in galaxy evolution given the abundance of evidence that suggests a cause-and-effect relationship between galaxies and the supermassive black-holes at their cores. A wide range of multiwavelength studies have already been carried out on this topic, from the sub-milliparsec scales of the accretion disc, to Megaparsec scales of the hot haloes into which giant radio-galaxies expand. However, there remain many open and unanswered questions that have been discussed widely in the literature, such as:

[Radio and mm/sub-mm]
* What is the role of jets in driving AGN outflows? How do outflows evolve?
* What are relativistic jets composed of and what powers their acceleration?
* What is the interplay between accretion, star formation and the ISM in the host galaxies?
* How do radio jets interact with galaxy haloes?
* What is the structure and composition of the dusty torus?
* How is accretion flow affected by the torus?
* How is accretion from the IGM affected by physics of the ISM?
* Which AGN processes produce the various emission lines observed?
* How does the morphology, stellar populations, dust and metallicity of a galaxy co-evolve with the AGN?
* What is the AGN X-ray corona’s origin and structure?
[Time Domain]
* What is the typical variability of AGN and how can we improve reverberation mapping of AGN?
* What are the causes and observables of extreme AGN variability?
[Multimessenger Signatures]
* How is gravitational-wave astrophysics affecting our understanding of AGN?
* Are AGN an important astrophysical source of high-energy neutrinos?

For cosmological simulations (e.g. SIMBA, IllustrisTNG, EAGLE and FIRE), which require AGN feedback to yield realistic galaxies across cosmic time, it is critical for physical constraints based on observations to inform theoretical models. For example, for the jets alone, we require cosmological simulations (to capture large-scale structure), relativistic MHD simulations (for radio-jet propagation), as well as GR-MHD simulations for the accretion disc--jet connection. All of this detail makes our proposed topic highly suitable for a GA Symposium rather than a shorter Focus Meeting.

In particular, we would like to emphasise the tremendous power of combining facilities on a wide wavelength range, including radio telescopes like MeerKAT, the MWA and ASKAP (precursor telescopes for the Square Kilometre Array). We also state the importance of facilities such as ALMA, the VLT, and the Vera C. Rubin Observatory in Chile, SALT in South Africa, as well as H.E.S.S. in Namibia. Additionally, there is great excitement for the upcoming ELT and AtLAST in Chile. In particular, the optical window provides crucial information on host-galaxy properties that are needed to understand the AGN and host-galaxy evolutionary connection. Optical integral field unit (IFU) spectroscopy is already available with VLT instruments and will soon become available on SALT. The IFU data remains a crucial method for the kinematic analyses of gas within and surrounding AGN host galaxies, allowing us to further understand how they are influenced by their nuclei. In addition, the JWST is expected to discover more high-redshift radio-emitting quasars and galaxies, extending our view of AGN to the reionisation edge of the Universe. Furthermore, upcoming space-based satellite missions such as the Japanese X-ray mission, XRISM, the NASA-led infrared satellite, SPHEREx, and LIGO, will provide key multiwavelength and multimessenger views of active galaxies.

We are also interested in discussing some of the technical challenges we may face in AGN observations and simulations, and for this we will ask delegates the following questions:
* How can we tackle the data-management challenges we shall face as a result of improved observing capability of next-generation telescopes?
* How can we work to strengthen synergies and cohesion between observers and theorists/simulators to possibly enhance the predictive power of theory/simulations and the interpretation of observations?

Additionally, we plan to incorporate a discussion on equity, diversity, and inclusion (EDI) in Astronomy during the symposium, which is pivotal for the whole community because researchers may not commonly set aside time to participate in EDI talks or see the relevance of EDI initiatives. We consider EDI to be an important way to bridge the gap between the local communities from which the SKA organisation has sourced talent and the broader Astronomy community.

Given the huge amount of resources spent on telescope proposals, data reduction, and analysis, we would also like to discuss the importance of so-called ‘null results’. In particular, we will discuss how such results are viewed and how a tendency to omit them from the literature may marginalise the work of many members of the community and ultimately negatively impact the progress of science. By discussing ways in which we can try to avoid such biases in the future, we should attain a more inclusive understanding of AGN, and an overall higher level of inclusivity by considering a fairer cross-section of all studies. This would also help to better inform the community concerning the feasibility of experiments, given a more complete record of past experiences.

Scientific Organising Committee (SOC) members:
Dr. Sthabile Kolwa [they/she] (University of Johannesburg, South Africa) - Co-Chair
Dr. Sarah V. White [she] (Rhodes University, South Africa) - Co-Chair
Prof. Tao An [he] (Shanghai Astronomical Observatory [SHAO], China)
Prof. Romeel Davé [he] (University of Edinburgh, UK)
Prof. Sara Ellison [she] (University of Victoria, Canada)
Assoc. Prof. Preeti Kharb [she] (National Centre for Radio Astrophysics [NCRA], India)
Dr. Vincenzo Mainieri [he] (European Southern Observatory [ESO], Germany)
Prof. Roberto Maiolino [he] (University of Cambridge, UK)
Dr. Andrea Merloni [he] (Max Planck Institute for Extraterrestrial Physics [MPE], Germany)
Assoc. Prof. Leah Morabito [she] (Durham University, UK)
Dr. Roderik Overzier [he] (Observatório Nacional, Brazil)
Dr. Annalisa Pillepich [she] (Max Planck Institute for Astronomy [MPiA], Germany)
Prof. Mirjana Pović [she] (Space Science & Geospatial Institute [SSGI], Ethiopia/[IAA-CSIC], Spain)
Prof. Elaine Sadler [she] (University of Sydney and CSIRO, Australia)
Assoc. Prof. Stas Shabala [he] (University of Tasmania, Australia)
Dr. Daniel Stern [he] (Jet Propulsion Laboratory [JPL]/California Institute of Technology, US)
Assoc. Prof. Ryan Trainor [he] (Franklin & Marshall College, US)

Notes on Logistics:

Our SOC comprises 17 Astronomers with expertise in observational and theoretical astrophysics. They operate at several institutions across the globe in Africa, North America, South America, Asia, Australia and Europe. Within the proposed SOC are scientists at different stages in their careers, ranging from early-career to mid-career and senior. In terms of gender distribution, 47% of our committee is female.

We would like to organise excursions to primary schools in under-served communities such as Molo Mhlaba, Luleka, Isiphiwo, and Chumisa in Khayelitsha), so that astronomers can pass on their knowledge and enthusiasm to the next generation of budding astronomers, building on the excellent work already done as part of Astro Molo Mhlaba. This will include using a mixture of media, such as short videos and craftwork, to help stimulate discussion of different astronomy topics, and therefore allow the interaction to be as engaging as possible. Additionally, we aim to host special training sessions for high-school teachers, through the Network for Astronomy School Education (NASE), and will organise public talks on recent space discoveries that have captured the public imagination. Local press and podcasters will be invited to record the events and report on them later. This would form part of a larger co-ordination for GA2024, in collaboration with the Communications, Education and Outreach Sub-Committee of the National Organising Committee.

Inclusion in Practice:
The symposium also aims to emphasise the importance of creating a safe and inclusionary academic environment for Astronomy research. We wish to have a roughly equal number of women scientists to speak at the conference and encourage more women and non-binary people to submit abstracts during the registration period. We will also ensure that participation extends to as wide a geographic distribution as possible, aided by a hybrid format. Our idea is to have one 4-hour session per day, over 4 days, with a changing start time so that virtual attendees around the world also have a fair chance to participate in the discussion

In the slide-show presentation sessions, we will have invited speakers give topic overview talks that will be followed by a set of talks on the specified topic. We plan to have a poster session where the speakers will be given 1 minute to advertise their work during the talk schedule. The posters will be on boards in a designated area, where delegates may commune during coffee and lunch breaks, as well as being made available online. There will be special emphasis on putting student, postdoc and early-career science on display especially for contributions from African institutions. With this, we hope to promote greater cross-continental scientific collaboration involving African researchers.

The funding will come from an IAU grant. Additional funds may be requested from AfAS.