HOW STARS MOVE AROUND AND WHAT THEY TELL US ABOUT GALAXIES’ MASSES, FORMATION AND EVOLUTION – From the Milky Way to Giant Elliptical Galaxies

Scientific Rationale

Galactic dynamics is fundamental to understanding the formation of galaxies, their internal evolution and current structure. Since the work of Eggen, Lynden-Bell and Sandage (1962, ApJ 136, 748) we know that “the time required for stars in the galactic system to exchange their energies and momenta is very long compared with the age of the galaxy. Hence knowledge of the(ir) present energy and (angular) momenta … tells us something of the initial dynamic conditions under which they were formed”. However, we also know now that a fraction of a galaxy’s stars is accreted from outside, and that for most others the distribution of energies and angular momenta evolves through internal dynamical processes and through the cosmological hierarchical merging and mass accretion.

While galactic dynamics has traditionally focused on the evolution of the stellar components of galaxies, many studies have shown that numerous aspects of galaxy evolution are strongly influenced by the interplay between the dynamics of stars, gas, dark matter, and supermassive black holes. Furthermore, stellar dynamics coupled with the knowledge of the stars’ chemical compositions and ages enables researchers to investigate how galaxies evolve over billions of years. This also involves the challenge of inferring their total mass distributions from observational data.

This workshop will bring together researchers to discuss new insights on the formation, dynamical evolution and mass distributions of galaxies, comparing results from individual stars in the Milky Way and nearby resolved galaxies with those obtained for integrated stellar populations in distant galaxies. Many of the recent advances are based on the current explosion of spectroscopic and kinematic data both from the Gaia satellite and stellar surveys for the resolved galaxies, and from JWST and integral field spectroscopy surveys for more distant systems. This is expected to continue: new data releases from Gaia, imminent spectroscopic surveys with 4MOST, WEAVE, DESI and the Subaru Prime Focus spectrograph, deep IFU surveys, JWST, and then the future ELT will advance our knowledge of galaxies but also challenge and transform our current views. This workshop aims to foster vibrant discussions and new ideas on future developments about galaxies in the Universe at large.

At this summer workshop at the Sexten Centre for Astrophysics we will celebrate Ortwin Gerhard’s 70^th anniversary

Deadline for submissions: March, 25th 2026

Organizers

SOC:
J. Alfonso Aguerri (IAC, Spain)
Ralf Bender (MPE, Germany)
Joss Bland-Hawthorn (Univ. Sydney, Australia)
Paola Di Matteo (Obs. de Paris, France)
Francesca Fragkoudi (Univ. Durham, UK)
Ken Freeman (RSAA, Australia National Univ., Australia)
Jesse van de Sande (Univ. of New South Wales, Australia)
Juntai Shen (Shanghai Jiao Tong Univ., China)
Monica Valluri (Univ. Michigan, USA)
Rosie Wyse (Johns Hopkins Univ., USA)
Magda Arnaboldi (Co-Chair, ESO, Germany)
Claudia Pulsoni (Co-Chair, MPE, Germany)

Contact: galaxydynamics2026@eso.org

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