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

Observatory's reception

09:15 - 10:00

Welcome Tassos Fragos

Lecture Vicky Kalogera

Introduction to POSYDON and binary black hole populations

10:00 - 11:00

Morning Lab 1 Basic Population Analysis

The basics of popsynth with POSYDON

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 13:00

Morning Lab 2 Basic Binary Populations

Manipulating & analyzing POSYDON popsynth data

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Jeff Andrews

Common Envelope Evolution in POSYDON

14:45 - 15:45

Afternoon Lab 1 Controlling CE Evolution in POSYDON

Learn what controls exist in POSYDON's CE evolution

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

Afternoon Lab 2 Customizing CE Evolution

Learn how to implement a custom step in POSYDON

09:15 - 10:00

Lecture Manos Zapartas

Supernova populations and extracting progenitor properties

10:00 - 11:00

Morning Lab 1 Profiles and surface properties

Understanding physical variations, kicks, and collapsing profiles

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 13:00

Morning Lab 2 SNe kicks and types

Learn how POSYDON models different SNe types and their kicks in stellar populations

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Mike Zevin

Star Formation History, Cosmology, Transient Rates

14:45 - 15:45

Afternoon Lab 1 Calculating Rates

Multi-metallicity & transient populations, initial conditions reweighting

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

Afternoon Lab 2 Selection Effects

Cosmological rates, star formation histories, and detectability

09:15 - 10:00

Lecture Tassos Fragos

X-ray Binaries & Super-Eddington Accretion

10:00 - 11:00

Morning Lab 1 Non-instantaneous Populations

Simulating the X-ray luminosity function

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 13:00

Morning Lab 2 Non-instantaneous Populations

Formation of wind-fed BH-HMXBs

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Max Briel

Stability of Mass Transfer

14:45 - 15:45

Afternoon Lab 1 Grid Visualization

Visualizing POSYDON's underlying MESA model grids

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

Afternoon Lab 2 Running a Grid

The basics of running your own MESA model grids for POSYDON

09:15 - 10:00

Lecture Seth Gossage

Tides & Magnetic Braking

10:00 - 11:00

Morning Lab 1 Detached Binary Evolution

Learn how POSYDON handles the evolution of detached binary systems

11:00 - 11:30

Coffee Break

Observatory's Cafeteria

11:30 - 13:00

Morning Lab 2 Custom Physics Prescriptions

Learn how to modify POSYDON's default prescriptions during detached evolution

13:00 - 14:00

Lunch

Observatory's Cafeteria

14:00 - 14:45

Lecture Aggelos Katsaggelos

Initial-final interpolation

14:45 - 15:45

Afternoon Lab 1 Interpolation in POSYDON

Understand the different interpolation strategies available in POSYDON

15:45 - 16:15

Coffee Break

Observatory's Cafeteria

16:15 - 17:45

School Recap / Farewell

Registration Is Now Open

Registration for the 2026 POSYDON School is now open and will remain open until April 30, 2026. Attendance is limited to 25 participants. To apply, please complete the registration form here: POSYDON School 2026 Registration Form.

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, after submitting the registration form, 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. We expect to notify participants after the application period closes.

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.