Program

Outreach

As part of the popularization of science, the IESC opens up to the local population with two public conferences at the Spaziu Culturale Cargese, one of which is musical.

3 stories of Gravity

Ugo Moschella, Universita dell'Insubria, Como, Italy

Science as a factor in human life is a latecomer. Art existed before the last ice age and is at least fifty thousand years old. Modern science, on the contrary, was born only four hundred years ago: Galileo was the father and gravity the midwife; historiography and tradition have assigned the role of founding mythical event to the story of Galileo’s Experiment at the Leaning Tower of Pisa. Two other tales, Newton Sitting Under the Apple Tree and Einstein’s Happiest Thought of His Life, articulate the history of our ideas about gravity.

Voyage aux Frontières de l'Univers

Nicolas Laporte, Laboratoire d'Astrophysique de Marseille, France

C'est dans la grotte de Lascaux que l'on trouve les indices les plus anciens de l'observation du ciel par l'Homme. Ces hommes préhistoriques pouvaient-ils imaginer que, 17 000 ans plus tard, leurs descendants développeraient des fusées de plus en plus puissantes, emmenant dans l'espace des satellites à la pointe de la technologie, avec pour seul objectif : repousser de plus en plus loin les limites de l'Univers observable ? Au cours de cette conférence, je vous propose de partir à la découverte de cet Univers, de la Terre jusqu'à la galaxie la plus lointaine, en passant par les millions de planètes et de galaxies qui le peuplent. Nous aborderons les grandes questions de l'astronomie moderne (sommes-nous seuls dans l'Univers, qu'est-ce que la matière noire, pouvons-nous remonter le temps, ...) et nous observerons les plus belles images que les télescopes (sur Terre ou dans l'espace) et les sondes spatiales ont capturées au cours de la dernière décennie. Nous aborderons également le futur de l'astronomie, notamment avec la mise en service en 2028 de l'Extremely Large Telescope.

Lectures

"In order to attend the school, basic knowledge is required in cosmology and extra-galactic physics.

Understanding galaxy and structure formation in a cosmological context

Katarina Kraljic, Observatoire Astronomique de Strasbourg

The formation and evolution of galaxies is intimately related to the growth of large-scale structure. Indeed, galaxies, and dark matter halos they reside in, form and grow within the cosmic web – the classification of large-scale structure as distinct environments, namely voids, sheets, filaments, and nodes. The development in the field of cosmological simulations and large galaxy redshift surveys over the past two decades allows us today to study the co-evolution of galaxies and halos with the cosmic web jointly in observations and simulations and compare the measurements with theoretical predictions. These lectures will give an overview of the curent understanding of galaxy and structure formation and evolution, emphasising the existing challenges both on the side of theory and observations and presenting future perspectives from ongoing and upcoming surveys.

  • Chapter 1: Formation and evolution of dark matter halos and galaxies
  • Chapter 2: Structure formation and the cosmic web
  • Chapter 3: The impact of the cosmic web on galaxies and halos
  • Chapter 4: The cosmic web as a tool to constrain cosmology and galaxy formation models

Useful reading

  • "Physical Models of Galaxy Formation in a Cosmological Framework" - Rachel S. Somerville, Romeel Davé, Annual Review of Astronomy and Astrophysics, vol. 53, p.51-113 (2015) arXiv:1412.2712
  • "Theoretical Challenges in Galaxy Formation" - Thorsten Naab, Jeremiah P. Ostriker, Annual Review of Astronomy and Astrophysics, vol. 55, issue 1, pp. 59-109 (2017) arxiv.org/pdf/0711.3358
  • "Galaxy Formation and Evolution" - Houjun Mo, Frank C. van den Bosch, Simon White, Cambridge University Press (2010)
More references for the most recent topics will be provided in the lectures.

Prerequisites

The lectures will be mostly self-contained

The Physics of Cosmic Reionization

Andrea Ferrara, Scuola Normale Superiore, Pisa, Italy

After recombination the cosmic gas was left in a cold and neutral state. However, as the first stars and black holes formed within early galactic systems, their UV and X-ray radiation induced a gradual phase transition of the intergalactic gas into the warm and ionized state we currently observe. This process is known as cosmic reionization. Understanding how the energy deposition connected with galaxy and star formation shaped the properties of the intergalactic gas is one of the primary goals of present-day cosmology. In addition, reionization back reacts on galaxy evolution, determining many of the properties of the high-redshift galaxy population that represent the current frontier of our discovery of the cosmos. In this Lecture we provide a pedagogical overview of cosmic reionization and intergalactic medium and of some of the open questions in these fields.

  • Lecture 1 : Star Formation in Primordial Gas
    • Chapter 1 – Cosmological ionisation fronts
    • Chapter 2 – Radiative transfer and numerical
  • Lecture 2 : The Initial Mass Function of First Stars
    • Chapter 3 – Reionization sources and implications
    • Chapter 4 – Experimental tests

Literature

Prerequisites

The course will mostly be self-contained.

The cosmic reionization: highlighting and modeling the physical processes

Pratika Dayal, Kapteyn Astronomical Institute, Groningen, The Netherlands

The Epoch of Reionization (EoR), the last major phase-transition of all of the hydrogen in the Universe, starts with the emergence of the first galaxies. Their stars, and possibly, black holes, produced the first photons capable of ionizing hydrogen and helium in the large-scale intergalactic medium (IGM). Over the past decade, a concordance picture has emerged in which, driven by these first galaxies, reionization ended within the first billion years of the Universe. This is supplemented by observatories such as the James Webb Space telescope (JWST) and the Atacama Large Millimetre Array (ALMA) yielding transformative insights on both the global properties and the interstellar media (ISM) of such galaxies well within the first billion years. Despite this enormous progress on the end stages of reionization, its key sources, patchy progress and interplay with early galaxy formation remain compelling frontiers in the field of astrophysics. This is because the process of reionization requires understanding the interplay between the small-scale physics of galaxy formation and its large-scale progress on cosmological scales. I will try to shed light on the multi-scale reionization process through the following lectures:

  • Lecture 1 : The small-scale physics of reionization: theory & observations
    • Chapter 1 – the emergence of the first sources and their physical properties
    • Chapter 2 – the stellar populations and black holes in the first sources
    • Chapter 3 – the escape of ionizing photons from galactic environments
  • Lecture 2 : The large-scale physics of reionization and its feedback on galaxy formation: theory & observations
    • Chapter 4 – propagation of ionization fronts in the (clumpy and metal-enriched) intergalactic medium
    • Chapter 5 – the inhomogeneous reionization background & its impact on early galaxy formation
    • Chapter 6 – using ionization fronts to shed light on dark galaxies (and dark matter) in the era of 21cm cosmology

Recommended reading

  • "Early galaxy formation and its large-scale effects" - Dayal & Ferrara, 2018, Physics Reports, 780, 1 arXiv:1809.09136
  • "Galaxy Formation and Reionization: Key Unknowns and Expected Breakthroughs by the James Webb Space Telescope " - Robertson, ARAA, 60, 121) arXiv:2110.13160

Prerequisites

The course will mostly be self-contained.

Key probes and methods to explore cosmic reionization

Xiaohui Fan, Department of Astronomy/Steward Observatory, University of Arizona

Reionization marks the last major phase transition in the history of the universe, when UV radiation from the earliest galaxies and AGN ionized the vast majority of the neutral hydrogen in the intergalactic medium and ended the cosmic dark ages. When the approximate timeline of reionization has now been established, the detailed physical processes that driven reionization remain uncertain. I will first discuss the evolution of the reionization-era IGM and its connection to early galaxy formation, then review a number of key observational methods to characterize the ionization state of the IGM at this epoch, using quasar absorption, galaxy surveys and CMB polarization.

  • Lecture 1 : Physical processes in the intergalactic medium (IGM) at the epoch of cosmic reionization and the IGM/galaxy connection
    • Chapter 1 – Gunn-Peterson effect
    • Chapter 2 – Sources of reionization
    • Chapter 3 – basic physics of 21cm emissions
  • Lecture 2 : Key observational probes of reionization history
    • Chapter 4 – IGM history probed by hydrogen absorption
    • Chapter 5 – ionizing photo escape from galaxies
    • Chapter 6 – IGM history probed in CMB and 21cm

Literature

Prerequisites

The course will mostly be self-contained.

The first stars and galaxies: cosmological simulations

Joakim Rosdahl, Centre de Recherche Astrophysique de Lyon

The formation and evolution of galaxies is a highly non-linear, multi-physics, multi-scales process that can only be approached theoretically using cosmological simulations to gain an understanding. With a synergy of observations and simulations evolving over the last three decades, a cohesive albeit incomplete picture has emerged of feedback-regulated galaxy growth over cosmic time. With the advent of the James Webb Space telescope, however, the plot has thickened, with seemingly overweight monster galaxies observed in the infancy of the Universe, and existing models appear to be increasingly challenged. I will review efforts to understand the formation of the first structures and the evolution of galaxies using cosmological simulations, with a focus on the first billion years and the epoch of reionization, and the challenges recently posed by JWST observations (which no doubt will have evolved significantly between the writing of this text and when the lectures will be given).

  • Lecture 1 : An overview of simulations of galaxy evolution
    • Chapter 1 – Different approaches to simulating the Universe
    • Chapter 2 – The physical processes, and how to model them
    • Chapter 3 – A history of cosmological simulations
    • Chapter 4 – A transition to a resolved inter-stellar medium
  • Lecture 2 : New challenges for simulations at high redshift
    • Chapter 5 – PopIII stars
    • Chapter 6 – Reionization with computers
    • Chapter 7 – New challenges with JWST
    • Chapter 8 – 'Observing' simulated galaxies
    • Chapter 9 – The future: more physics, bigger computers, better methods

Literature

Prerequisites

The lectures are self-contained and no prior expertise in computational astrophysics is assumed.

The first stars and galaxies: deep surveys

Rebecca Bowler, The University of Manchester.

To probe the reionization era requires samples of galaxies and AGN at very high redshifts. Using deep photometric surveys it has been possible to select galaxies probing up to the first few hundred million years after the Big Bang. In the first lecture I will describe the main techniques and key datasets for the selection and study of galaxies in the reionization era within deep photometric surveys. The second lecture will focus on the results of these surveys in terms of basic galaxy properties - the number density, colours and physical properties. I will end by presenting a comparison with simulations, to put these observables into context, and open questions in the field.

  • Lecture 1: Searching for the first stars and galaxies - techniques
    • Chapter 1 – Observational signatures of the first galaxies
    • Chapter 2 – Photometric surveys, the power of JWST to Euclid
    • Chapter 3 – Selection techniques: principles and challenges
  • Lecture 2: Searching for the first stars and galaxies - results and outlook
    • Chapter 4 – Overview of galaxy samples to-date
    • Chapter 5 – Distribution functions (luminosity function, mass function etc)
    • Chapter 6 – Comparison to simulations and open questions

Optional reading:

Prerequisites

The course will mostly be self-contained.

The first stars and galaxies: deep surveys

Roberto Maiolino, University of Cambridge

We are witnessing an epochal leap in the exploration of the primeval Universe and in understanding of the early formation of galaxies, stars and black holes. Many of these exciting recent developments have been possible especially thanks to the James Webb Space Telescope (JWST), which has opened a totally new discovery space. The lectures will provide an overview of the recent progress in this field, mostly from an observational perspective. I will review the current findings on the stellar populations and star formation histories in distant galaxies, as well as their properties of their interstellar and circumgalactic medium. I will discuss how these results provide important constraints on the formation, evolutionary and transformation processes of galaxies in the early Universe. I will also give an overview of the intriguing and puzzling findings on the connection between star formation and the formation and growth of black holes at their centres. I will conclude by summarising the open questions and the prospects of tackling them with future facilities.

  • Chapter 1 - Properties of the early stellar populations
  • Chapter 2 - Kinematical and dynamical properties of early galaxies
  • Chapter 3 - Properties of the interstellar and circumgalactic medium in early galaxies
  • Chapter 4 - Early chemical and dust enrichment
  • Chapter 5 - The interplay between galaxies and early black holes
  • Chapter 6 - Clustering of primeval galaxies
  • Chapter 7 - Prospects from future facilities

Literature

While there are not yet comprehensive overviews/papers on the most recent findings in the early universe, it would be helpful some familiarity with previous studies at lower redshift; the following reviews may be helpful:
  • "Star-Forming Galaxies at Cosmic Noon" - N. M. Förster Schreiber, S. Wuyts, Annual Review of Astronomy and Astrophysics, vol. 58, p.661-725, arXiv:2010.10171. arXiv:2010.10171
  • "De re metallica: The cosmic chemical evolution of galaxies" - R. Maiolino, F. Mannucci, The Astronomy and Astrophysics Review, Volume 27, Issue 1, article id. 3, 187 pp. arxiv.org/abs/1811.09642.

Prerequisites

Basic introductory course(s) on extragalactic astronomy, galactic structure and galaxy basic properties.

Characterizing the sources of cosmic reionization

Laura Pentericci, INAF Osservatorio Astronomico di Roma.

The nature of the sources emitting sufficient Lyman continuum (LyC) photons to conclude cosmic reionization by z~6 remains elusive. Competing models of the reionization process include those driven by abundant faint galaxies or rare but more luminous ones, and both can account for the evolving neutrality of the intergalactic medium assuming different values of LyC escape fraction. I will give an overview of the physical properties of early cosmic ionizers including in particular their photon production efficiency and the escape fraction of the produced ionizing photons, and how these two key quantities depend on the nature of the stellar populations.

  • Lecture 1
    • Chapter 1 – Modeling the physical properties of early galaxies
    • Chapter 2 – The photon production efficiency of galaxies in the EoR
  • Lecture 2
    • Chapter 3 – Inferring Lyc escape fractions at high redshift
    • Chapter 4 – The evolution of the total ionizing output from galaxies and AGN

Literature

Prerequisites

The course will mostly be self-contained.

Black holes and AGN in the early universe

Marta Volonteri, Sorbonne University - Institut d’Astrophysique de Paris (IAP).

Theoretically, models for the formation of massive black holes in the cosmological context have been developed in the early 2000s, following the seminal ideas of Martin Rees in 1978. The existence of black holes in the first billion years of the Universe has been proven by the discovery of bright quasars first (in the early 2000s) and recently by fainter AGN detected thanks to JWST (since 2023). These discoveries have also raised many questions as to how massive black holes form and how some of them grow very fast to explain the properties of the observed sources. I will provide an overview of the astrophysical aspects of massive black holes in the first billion year or so of the Universe, as well as how they can be detected when they accrete matter — through light — and when they merge — through gravitational waves.

  • Chapter 1 – Formation of massive black hole “seeds”
  • Chapter 2 – Massive black hole growth: accretion and mergers
  • Chapter 3 – Detectability of massive black holes: AGN and gravitational waves

Literature

  • Section 2 of "Astrophysics with the Laser Interferometer Space Antenna" - Living Reviews in Relativity, Volume 26, Issue 1, article id.2" https://arxiv.org/abs/1710.05835
  • "The origins of massive black holes" - Volonteri, M., etal. (2021) Nature Reviews Physics, Volume 3, Issue 11, p.732-743 https://arxiv.org/abs/2110.10175

Prerequisites

Familiarity with astrophysical concepts, and ideally some basics in galaxy evolution.

Exploring the First Billion Years with 21 cm line

Saleem Zaroubi, Kapteyn Astronomical Institute

The course will review the current status of exploring the first billion years of cosmological evolution using the redshifted 21 cm line, which requires very low-frequency radio observations. It will start with presenting the physics of the 21 cm line and its connection to the physical properties of the intergalactic medium. Then, we will define the three eras of the first billion years (The Dark Ages, Cosmic Dawn, and Epoch of Reionization) in terms of redshifted 21 cm observable. The topology and evolution of the redshifted 21 cm signal will be discussed. The relationship between such topologies and cosmological and structure formation models will be presented. The course will then focus on the observational status of the field and the various projects that are currently running or planned for the near future. The course will show the latest results from these experiments. The course will end with a discussion of the future prospects of the field.

  • Lecture 1 : The Redshifted 21 cm Cosmological Probe: Theory and Modeling
    • Chapter 1 – Physics of the 21 cm line
    • Chapter 2 – The 21 cm brightness temperature and its relation to the IGM
    • Chapter 3 – The three eras of the first billion years in terms of the redshifted 21 cm observable
    • Chapter 4 – The evolution of the 21 cm and its relation to Cosmology and structure formation
  • Lecture 2 : The Redshifted 21 cm Cosmological Probe: Observation and Interpretation
    • Chapter 5 – The current observational effort and its various strategies
    • Chapter 6 – The main Observational and data analysis challenges
    • Chapter 7 – Recent results and their implications
    • Chapter 8 – Future prospects of the field

Literature

  • "21 Centimeter Tomography of the Intergalactic Medium at High Redshift”, P. Madau, A. Meiksin and M. J. Rees. ApJ, 475:429 (1997) https://arxiv.org/abs/astro-ph/9608010
  • "Cosmology at low frequencies: The 21 cm transition and the high-redshift Universe" - S. R. Furlanetto, S. P. Oh, and F. H. Briggs. PhysRep, 433:181–301 (2006) https://arxiv.org/abs/astro-ph/0608032>
  • "The Epoch of Reionization" - Zaroubi, S. (2013) A chapter in the book entitled "The first galaxies: Theoretical Predictions and Observational Clues" Wiklind, Tommy, Mobasher, Bahram, Bromm, Volker (Eds.) Astrophysics and Space Science Library 396, page 45. https://arxiv.org/abs/1206.0267.
  • "Reionization and the Cosmic Dawn with the Square Kilometre Array”, Mellema, G., et al. (2013). Experimental Astronomy 36, 235-318. https://arxiv.org/abs/1210.0197.
  • "Peering into the dark (ages) with low-frequency space interferometers”, Koopmans et al. (2021) - https://arxiv.org/abs/1908.04296.

Prerequisites

The course will mostly be self-contained.

Hands-on Workshops

Two hands-on workshops will be proposed during the school. You will find the details below. The links to downloadable materials are also provided. We recommend that you download the latest version of these files just before the school starts.

Documents/tools to download and software to install in preparation for the workshop from https://cigale.lam.fr/.

Workshop: Using the CIGALE galaxies SED fitting code

Patrice Theule, Laboratoire d'Astrophysique de Marseille

During this workshop, you will learn how to use the galaxies SED fitting code CIGALE on various types of galaxies. As an exercise, you will have to perform a combined spectro-photometry SED fitting of this sample and then plot the results on a SFR-mass diagram and on a BPT diagram for instance. We will discuss the use of spectroscopy in galaxies fitting. You will work on a sample of nearby galaxies with observations spanning a good wavelength coverage: the Sings/KINGFISH sample.

Literature

Prerequisites

A basic knowledge on extragalactic physics is compulsory.

Fitting spectrophotometric data with CIGALE to better understand galaxies in the early universe

Denis Burgarella, Laboratoire d'Astrophysique de Marseille

JWST, ALMA, NOEMA and other facilities world-wide and beyond provide us with a unique set of multi-wavelength data from the most energetic range to radio. Combining these data and comparing them to models is crucial to better understand galaxie, their formation and their evolution. Photometric data are certainly very useful. However, JWST opened up a new world by securing very-high-quality spectra well within the epoch of reionization, and to z > 10. After an introduction on the input parameters that define the set of models, we will move to experimental tests on a pre-defined sample, focusing on a high redshift sample.. You could also bring you own sample of data that could include any photometric data plus (as of Feb. 2025) NIRSpec prism data.

Literature

Prerequisites

In order to use CIGALE, we recommend to read the paper Boquien et al. (2019) that describes the traditional photometric + spectral indices and lines fitting. By October 2025, we hope to have a new paper describing the spectrophotometric fiiting (Burgarella et al. 2025).

Short talks and Posters

Seminars complete the program and PhD students, as part of their training, are invited to submit a short communication or a poster. These one will be exhibited throughout the week and will serve as a support for the discussions.

Web development: Thierry Masson (CPT, Marseille)