ii8 m/M

Interstellar physics from milli to Mega parsec

The Interstellar Institute was created as an answer to the inherent difficulty of studying the utterly complex and diverse physics of the evolution of diffuse baryonic matter. The I2 sessions are designed as opportunities to bring together numerical, theoretical, methodological, and observational perspectives through close interaction among researchers across the field. The goal is to identify and discuss key interstellar problems at all scales, examining the physical processes that govern the global evolution of gas and dust. The Interstellar Institute will reconvene in 2026 to continue its exploration.

Diffuse baryons in the Universe reside in the interstellar, circumgalactic, intergalactic, and intracluster media. Across these environments, baryonic matter evolves over many orders of magnitude in temperature, density, and velocity. Observational diagnostics and numerical approaches vary widely in order to characterize matter from the warm–hot intergalactic medium (WHIM) down to dense gravitationally bound cores. Comparing techniques, questions, and results across scales and environments is profoundly enriching, providing critical insight into the physical channels through which matter and energy flow along the astrophysical cascade.

At II8, we return to the vision outlined in The Grand Cascade: to juxtapose expertise across diffuse environments and reveal the hidden coherence of the “great power law in the sky.” By connecting scales, methods, and communities, we seek to refine our broader picture of cosmic structure formation.

Registration

A temporary interstellar laboratory

A day at the Interstellar Institue

On any given day, about 50-55 participants are present at the Institut Pascal. It is a temporary interstellar lab for three weeks. Each day starts in the main amphitheatre with four 15min talks from participants - anyone can give a talk if they want - followed by enough time for discussion. We then plan the rest of the day together; everyone is welcome to propose discussion topics to be held later in one of the meeting rooms / common area / amphitheatres. The afternoons are free, this time is yours to work, discuss, imagine, explore... you can work alone, with colleagues or new collaborators, take part in optional group discussions. Imagine a lab where the person that can answer your new question is probably down the hall. This free time is when the magic happens !

A place and time to reflect

The Interstellar Institute meetings are designed to provide a time for synthesis, make an inventory of recent studies, discuss new data analysis techniques, to lay out big pictures, test new ideas and identify key questions, clarifying what should be addressed next. For that purpose, i2 meetings bring together experts in anything interstellar (gas, dust, cosmic rays, magnetic field, turbulence, star formation, feedback, ...) with a focus on reaching a balance between multi-wavelength observations, numerical simulations / theory, and data analysis, but also a balance of experience levels, from PhD students to more senior scientists.

With 60 desks, plenty of common areas and meeting rooms, the Institut Pascal has been designed for this type of collaborative work. It is located on the Paris-Saclay University campus, easily reached by public transports.

Registration

Important dates

March 1st, 2026 : registration opens
April 30, 2026 : registration closes
May 15, 2026 : announcement of selection
May 15 - June 30, 2026 : abstract submission for talk
July 15, 2026 : publication of the program
September 21, 2026 : start of ii8
October 9, 2026 : end of ii8

Registration

Scientific Organising Committee

Susan Clark | Stanford University, USA
Joanne Dawson | Macquarie University, Australia
Naomi McClure-Griffiths | Australian National University, Australia
Marc-Antoine Miville-Deschênes | Ecole Normale Supérieure, Paris, France