Habilitation à Diriger les Recherches - Yanbin Yang

Value of the Information & Strength of the Argument

The presentation provides valuable insights into the formation and evolution of spiral galaxies, particularly through detailed numerical simulations. The argumentation is solid, based on comparisons between simulations and observations, and the speaker systematically tests hypotheses. The work on M31 is particularly compelling, as the simulations reproduce several observed features and make testable predictions. The speaker also acknowledges limitations, such as the resolution of cosmological simulations and the uncertainty in M31’s proper motion, which strengthens the credibility of the arguments.

Scientific Rigor, Source Quality, Title Accuracy

The scientific rigor is high, with the speaker referencing specific observational surveys (e.g., IMAGES, Pan-Andromeda Archaeological Survey) and simulations (e.g., TNG, FIRE). The sources are appropriate and well-integrated. The title accurately reflects the content, which is a formal presentation of the speaker’s research. The talk is well-structured and the methodology is clearly explained.

The title accurately reflects the content: a habilitation defense presenting the speaker's research on galaxy modeling, focusing on spiral galaxies and the Local Group.

8/10

The presentation is based on original research, including detailed simulations and comparisons with observations. The speaker demonstrates a deep understanding of the subject and uses established methodologies. However, the talk is a habilitation defense, which is a formal academic presentation, and the content is not peer-reviewed in this format. The speaker acknowledges limitations and uncertainties in the models.

Markers derived by PSI from the transcript: the creator did not define chapters.

• 02:00Introduction to galaxy morphology and the need for detailed simulations.
• 10:00Discussion of observational studies of high-redshift galaxies using FLAMES/GIRAFFE.
• 20:00Presentation of kinematic classification of galaxies and the fraction of perturbed systems.
• 30:00Introduction to galaxy merger simulations and the grid of initial conditions.
• 40:00Comparison of simulation results with observed galaxy morphologies.
• 50:00Focus on M31: reproducing the giant southern stream and other features.
• 1:00:00Discussion of the predicted tidal tail and its connection to the Milky Way.
• 1:10:00Introduction to the Local Group and the plane of satellites around M31.
• 1:20:00Techniques for simulating the intergalactic medium and its effects on dwarf galaxies.
• 1:30:00Summary of contributions and future directions.

• IMAGES survey — Observational study of intermediate redshift galaxies.
• Pan-Andromeda Archaeological Survey (PAndAS) — Survey of the Andromeda galaxy's halo.
• TNG simulation — Cosmological simulation used for comparison.
• FIRE simulation — Cosmological simulation used for comparison.

• Observations of high-redshift galaxies — The speaker's findings on perturbed kinematics are consistent with other observational studies.
• Simulations of galaxy mergers — Other simulations have also shown that mergers can produce spiral features.

• Cosmological simulations — Cosmological simulations often struggle to reproduce the observed fraction of spiral galaxies, which motivates the detailed merger simulations presented.