Selim C. Hotinli

Selim C. Hotinli

P. J. E. Peebles Fellow

Cosmic Ecosystems


In the past three decades, one of the most transformative insights in cosmology has been the realisation that the formation and evolution processes of cosmic structures such as supermassive black-holes, galaxies and clusters are deeply interconnected with the vast cosmic web that underpins the Universe. These processes do not happen in isolation, but are part of a dynamic ecosystem where matter and energy flow across scales, driving the growth and transformation of cosmic environments. Understanding this complex system, in particular the circum-galactic medium (CGM), is not only key to deciphering how matter is cycled and redistributed through accretion via filaments and outflows from AGN and supernovae, but also crucial for unlocking the next generation of discoveries in areas such as dark matter, the behaviour of the cosmic web, the forces that shape cosmic evolution, and more.

This conference seeks to bring together cosmologists and astrophysicists to foster collaborative exploration of these interconnected cosmic ecosystems. By focusing on how structures interact with their environments across cosmic scales, this conference aims to catalyse groundbreaking discoveries in both astronomy and physics, providing fresh insights into the forces that govern the Universe. Special attention will be given to the joint analysis of large-scale structure and weak gravitational lensing data from surveys such as DESI, Euclid, LSST and Roman with CMB data from the Simons Observatory and CMB-S4, as well as how these can be integrated with observations of JWST, and existing and upcoming observations of X-ray emission, UV/X-ray absorption toward quasars, 21-cm emission, and FRBs.

The goal is to explore the complementarity of these data sets and how their alignment can provide new insights into the interconnected processes shaping cosmic environments, particularly through joint modelling and simulations of many phases of gas and feedback across different regimes. Attention will also be given to bridging the gap between how cosmologists and astronomers approach the CGM, either top-down large-scale and hot and virial phase, vs bottom-up, cooler phases, at smaller scales.

Please register using: https://events.perimeterinstitute.ca/event/927/

Topics will include:

The conference will cover a range of themes that focus on delineating and connecting the different scales and phases of the CGM, with a clear emphasis on their links to cosmological themes. The below themes aim to build a coherent picture of the cosmic ecosystem by systematically linking scales and phases.

Together, these helps provide a multi-faceted exploration of how baryonic physics connects all aspects of the universe and form a unified understanding of it across time and space.

These themes are detailed further below.

1. Connecting the Smallest to the Largest: From Subgrid Feedback Physics to Cosmic Large-Scale Structure

Scope: This theme bridges the smallest scales of feedback, such as AGN and supernovae (SNe), with their impact on the large-scale structure (LSS) of the universe. It explores how microphysics (e.g., jets, winds, and turbulence) propagates through simulations and influences the baryonic distribution and clustering on cosmological scales.

Example Topics:

2. Linking Hot Gas to Cold Gas: Baryon Cycling in the Cosmic Ecosystem

Scope: This theme connects the hot ionized gas (e.g., in galaxy clusters and CGM) to cold neutral/molecular gas (e.g., in star-forming regions). It investigates how feedback processes mediate phase transitions, driving the baryon cycle between these reservoirs.

Example Topics:

3. From the Circumgalactic Medium to the Intergalactic Medium: Feedback’s Reach Beyond Galaxies

Scope: This theme examines how feedback-driven processes in the circumgalactic medium (CGM) extend into the intergalactic medium (IGM). It focuses on the transition from galaxy-scale to cosmic web-scale interactions, highlighting turbulence, outflows, and the redistribution of metals and energy.

Example Topics:

4. Tying the Diffuse to the Dense: Connecting Gas Phases and The Role of Turbulence

Scope: This theme focuses on the interplay between diffuse gas (e.g., ionized or neutral IGM) and compact structures (e.g., molecular clouds and galaxies), include discussions on turbulence and cosmic ray interactions. It highlights how energy transfer and phase transitions bridge vastly different density and temperature regimes.

Example Topics:

5. Bridging the Present and the Past: Feedback’s Role in Linking Cosmic History to Current Observables

Scope: This theme connects feedback’s influence on the cosmic ecosystem across time, from early epochs of structure formation to the present universe. It examines how feedback processes evolve with cosmic time and leave imprints observable today, such as in the Lyman-alpha Forest, SZ effect, and FRBs.

Example Topics:

The time has never been more right to unify these fields, as advances in observation, theory and simulations are poised to open new paths to revealing the cosmos’ most profound mysteries.

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Organizing Committee (LOC)

Scientific Organizing Committee (SOC)

Confirmed Speakers

Additional invited speakers will be added as they are confirmed.