Special Session SS4 

The interplay between gravity and baryons: Insights from low surface brightness galaxies

Aims and scope

Current observations reveal that low surface brightness galaxies (LSBGs) may constitute up to half of the galaxy population, spanning a wide mass range from low-mass dwarfs to giant systems with stellar masses comparable to, or even exceeding, that of the Milky Way (e.g. Malin 1). Compared to their high surface brightness (HSB) counterparts, LSBGs exhibit more extended mass distributions for a given baryonic mass, contain large reservoirs of neutral hydrogen, preferentially inhabit sparse environments, and display lower star formation rates, suggesting slower evolutionary pathways.

The wealth of data from existing and upcoming observational surveys is set to shed light on the LSB Universe. It also raises important questions from a theoretical/numerical side:

  • Can simulations reproduce the observed properties of LSBGs?
  • How can we disentangle the roles of dark matter and baryonic physics (e.g. sub-grid prescriptions) in their evolution?
  • How can LSBGs be used to test dark matter models and, more broadly, models of gravity (e.g. with rotation curves, disc stability)?


Looking ahead:

  • How can cosmological simulations make testable predictions existing and upcoming surveys?
  • What kinds of multi-wavelength observations (e.g. HI, H?, NIR) are needed to probe these systems in greater detail?

    Over the proposed one-day program, organized in three separate sessions, we aim to address these questions, with a primary focus on constraining theoretical models using available numerical tools, whilst placing strong emphasis on observational contributions. To realise the full potential of data from upcoming program will emphasize the use of numerical tools to confront models with current data, while preparing the community, in advance, to fully exploit forthcoming datasets. Our overarching goal is to establish a theoretical and numerical roadmap to interpret the LSB Universe in the era of next-generation surveys.

    Programme

    The special session is categorised into three main sessions:

  • Galaxy scaling relations: An LSBG perspective
  • Cosmological and idealised simulations: Formation and evolution of LSBGs
  • Dark matter and beyond: Testing gravity models using LSBGs

    Invited speakers

  • Federico Lelli (INAF - Arcetri Astrophysical Observatory)
  • Azadeh Fattahi Stockholm University)
  • Benoit Famaey (Observatoire Astronomique de Strasbourg)

    Scientific organisers

  • Srikanth T. Nagesh (École polytechnique fédérale de Lausanne)
  • Oliver Müller (École polytechnique fédérale de Lausanne)
  • Elizabeth A.K Adams (ASTRON, and Kapetyn Astronomical Institute)
  • Francine Marleau (University of Innsbruck)
  • Anna C. Wright (Flatiron Institute)
  • Yves Revaz (École polytechnique fédérale de Lausanne)
  • Luis Enrique Pérez-Montańo (Zhejiang University)

    Contact

    Srikanth T. Nagesh: srikanth.nagesh @ epfl.ch; eas2026-ss4 @ listes.epfl.ch

    Updated on Tue Jan 13 15:14:04 CET 2026

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    European Astronomical Society