2026 POSYDON School

2026 POSYDON School

24-27 August,

Geneva Observatory
Versoix, Switzerland

2026 POSYDON School

Join us in Geneva for the 2026 POSYDON School and learn how to use POSYDON, a state-of-the-art binary population synthesis code now in its second version. This four-day workshop is designed to help participants incorporate POSYDON effectively into their own research.

Through a series of hands-on labs, we will explore astrophysical scenarios such as mass-transfer stability, supernovae, binary black-hole populations, and more, showcasing how POSYDON can advance your research goals. Participation is limited to 25 attendees to keep the school highly interactive and discussion-driven.

Where

Geneva Observatory,
Chemin Pegasi 51,
CH-1290 Versoix,
Switzerland

When

Monday to Thursday

24-27 August

School Program

08:45 - 09:15

Registration

Participant check-in and welcome at the Geneva Observatory.

09:15 - 09:30

Welcome Tassos Fragos

09:30 - 10:00

Lecture Vicky Kalogera

Introduction to POSYDON and Binary Black-Hole Populations

Overview of the POSYDON framework and its applications to compact-object binary populations.

10:00 - 11:00

Lab Basic Population Analysis

Introduction to binary population synthesis workflows using POSYDON.

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 13:00

Lab Basic Binary Populations

Manipulating and analyzing POSYDON population synthesis outputs.

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Seth Gossage

Tides and Magnetic Braking

Modeling angular momentum evolution in detached binaries.

14:45 - 15:45

Lab Detached Binary Evolution

Simulating detached binary evolution channels.

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

Lab Detached Binary Evolution

Simulating detached binary evolution channels.

09:15 - 11:00

Lab Grid Visualization

Exploring and visualizing stellar evolution grids in POSYDON.

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 12:00

Lecture Jeff Andrews

Common Envelope Evolution in POSYDON

Physical treatment and implementation of common-envelope evolution in POSYDON.

12:00 - 13:00

Lab Controlling CE Evolution in POSYDON

Exploring and modifying common-envelope prescriptions in simulations.

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Manos Zapartas

Supernova Populations and Extracting Progenitor Properties

Connecting stellar evolution calculations with supernova populations and progenitors.

14:45 - 15:45

Lab Profiles and Surface Properties

Working with stellar structure profiles and surface quantities in POSYDON outputs.

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

Lab SN Kicks and Types

Exploring supernova prescriptions, natal kicks, and transient classifications.

09:15 - 10:00

Lecture Tassos Fragos

X-ray Binaries and Super-Eddington Accretion

Modeling X-ray binary populations and accretion physics in POSYDON.

10:00 - 11:00

Lab Non-instantaneous Populations

Simulating evolving X-ray binary populations and luminosity functions.

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 12:00

Lecture Mike Zevin

Star Formation History, Cosmology, and Transient Rates

Modeling transient populations across cosmic history.

12:00 - 13:00

Lab Calculating Rates

Computing astrophysical event rates from population synthesis outputs.

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 15:45

Lab Selection Effects

Understanding observational selection effects in transient populations.

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

Lecture Eirini Kasdagli

Spectral synthesis with POSYDON

09:15 - 10:15

Lab Customizing CE Evolution

Implementing custom evolutionary steps and workflows in POSYDON.

10:15 - 11:15

Lab Custom Physics in Detached Evolution

Implementing and testing customized physical assumptions in POSYDON.

11:15 - 11:45

Coffee Break

Observatory's Cafeteria

11:45 - 13:00

Lab Running a new Grid

Practical introduction to running and managing simulation grids.

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Aggelos Katsaggelos

Initial-final Interpolation

Interpolation techniques used within the POSYDON framework.

14:45 - 15:45

Lab Interpolation in POSYDON

Hands-on exploration of interpolation methods and strategies.

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 16:45

Closing Session School Recap / Farewell

Summary of the school and concluding discussion.

Registration Is Now Closed

Registration for the 2026 POSYDON School is now closed. Attendance is limited to 25 participants, and we expect to notify applicants after the application review is complete.

There is no registration fee for the school. We will provide free coffee breaks and lunches to all participants throughout the week.

We ask all participants to plan to attend the full school from August 24 to August 27, 2026.
Participants are expected to have a solid background in the physics of single and binary stellar evolution, typically acquired through advanced undergraduate or graduate-level coursework, or through relevant research experience.
Participants are not expected to know how to use POSYDON but should bring a personal laptop for the hands-on sessions.
We recommend that participants read the instrument papers for POSYDON v1 and POSYDON v2 to familiarize yourself with the code infrastructure.
Familiarity with Python and command line usage is expected.
For PhD, Master's, and Bachelor's students, we will reach out to your supervisor to confirm that you meet the availability, funding, and preparedness requirements. Make sure you have your supervisor's permission before applying.

Limited financial support may be available. Applicants for whom financial support is necessary for participation should send a separate email to posydon.school@gmail.com explaining and motivating their request.

Please email posydon.school@gmail.com with any questions or concerns.

School Venue

The 2026 POSYDON School will be hosted at the Geneva Observatory in Versoix, just outside Geneva, providing an ideal setting for a focused and interactive training school.

Geneva Observatory, Versoix

The school will take place at the Geneva Observatory, located at Chemin Pegasi 51, CH-1290 Versoix, Switzerland. You can also find the venue on Google Maps.

Where to Stay

Participants are asked to arrange their own accommodation. We have reserved a limited number of rooms at the Lake Geneva Hotel in Versoix, which is the most convenient location for access to the Geneva Observatory. To take advantage of the secured rates, participants should make their reservation using the provided booking link. Reserved rates are 189 CHF/night for single occupancy and 209 CHF/night for double occupancy, including breakfast.