The summer 2024, two years after the beginning of JWST science operations, will be the right time to gauge its impact on the quantitative characterization of galaxies. This symposium will gather the main results from the peak of star formation activity at z~2 to the first galaxies alongside the latest major achievements from sensitive instrumentation at optical/near-infrared to millimeter wavelengths and theoretical interpretations.

More specific goals of the symposium follow:

First galaxies: statistical properties Detecting and characterizing first galaxies all the way to redshift ~20 has been a main focus of JWST so far. This session will discuss what we are learning from JWST observations and models in the EoR, covering available surveys at z > 6 (e.g. CEERS, GLASS, JADES, JEMS, PRIMER, NGDEEP, FRESCO, PANORAMIC) and synergies with other datasets (e.g., ALMA, NOEMA, VLT) focusing on: (i) the overall galaxy population, (ii) the progress of cosmic star-formation in the first billion years, with an emphasis put on the galaxy main sequence, luminosity function and stellar mass function. These distribution functions will be compared to models of galaxy formation specifically focusing at z>6 and implementing a range of different feedback processes and star-formation recipes.

First galaxies: from spectral diagnostics to physical properties With statistically robust samples of confirmed high-redshift galaxies in hand, and much improved constraints with JWST, it is the right time to discuss the nature of the first generation of galaxies interpreting their spectral diagnostics in terms of stellar/BH population properties (e.g., role of clusters, peculiar ionizing sources, role of early accreting black holes or binary stars) and ISM environment through which their photons travel before escaping. Chemical and radiative feedback processes (i.e. dust and metals production and H2 formation) from stars and central black holes (e.g., ionization state and gas temperature) will be covered and their impact on the multiphase ISM addressed. This session will also be an opportunity to discuss the adequacy of the modeling and interpretive tools in the physical regimes relevant to the earliest cosmic times.

The Baryon cycle Gas flows in and out galaxies and radial flows within disks are the mechanisms that maintain, promote, or suppress star formation in galaxies. Feedback from star formation and/or AGN plays a key role in regulating such flows. This active field of research for the ionized and the neutral phases (especially with the VLT and ALMA/NOEMA, respectively) is providing key physical insights essential to the interpretation of the observed stellar properties of galaxies across cosmic time.

First appearance and growth of quenched galaxies Besides actively star-forming galaxies at very high redshifts, JWST has also revealed the unexpected presence of both low- and high-mass quenched galaxies already in place in the first few billion years after Big Bang, and some of them had their star formation suppressed around, or even before, the epoch of reionization. Mapping the growth of such a population, in number, mass, size and morphology, is now being accomplished from cosmic dawn to noon, an indispensable step towards understanding the physical origin of star-formation quenching.

From early chaotic assembly to ordered disks First galaxies appear to be compact dwarfs, but by cosmic noon (z~2) most galaxies have settled into orderly-rotating disks. The detailed mapping of this transition as a function of time, for galaxies of all masses, is paramount to understanding the structural and stellar mass assembly of galaxies. With JWST, and the growing body of complementary resolved millimeter interferometric observations of gas kinematics, this is now well underway and will feature as a main item in this Session.

Structure and Dynamics of galaxies High spatial resolution observations from the ground (e.g., as currently being done with ALMA/NOEMA and ERIS at the VLT) and from space (e.g. NIRSpec IFU on the JWST) are revealing the internal kinematics and dynamics of star-forming galaxies, allowing us to gauge the relative distribution of baryon and dark matter on galactic scales and their interplay within galaxies in the early Universe.

Galaxy scaling relations (from NOON to DAWN) Scaling relations between fundamental properties, specifically SFR, size, gas, dust, metal content, and angular momentum all as a function of stellar mass and cosmic time, are key to constraining the dominant mode and timescale of galaxy evolution. Galaxy surveys over the last two decades have revealed the existence of tight and smoothly evolving scaling relations out to cosmic noon and beyond. Access to the rest-frame near-IR regime now provided by JWST will allow a most accurate determination of stellar masses as well as stellar population and size properties, setting scaling relations from cosmic noon to cosmic dawn on more solid grounds.

Programme

The Symposium is organized in seven blocks of 1.5 hours. It will include a selection of invited review speakers (25+5mins), invited keynote talks (12+3mins) and contributed talks (12+3mins).

The main broad topics of the Session are summarized below:

• First galaxies
• The Baryon cycle
• First appearance and growth of quenched galaxies
• From early chaotic assembly to ordered disks
• Structure and Dynamics of galaxies

Invited speakers

• Adam Carnall (University of Ediburgh, UK)
• Pratika Dayal (Groningen University, The Netherlands)
• Roberto Maiolino (University of Cambridge, UK)
• Laura Pentericci (INAF - Rome, Italy)
• Linda Tacconi (MPE - Germany)
• Stijn Wuyts (Bath University, UK)
• Emanuele Daddi (CEA, France)
• Pablo Perez-Gonzalez (CAB, Spain)

Scientific organisers

• Laia Barrufet De Soto (University of Edinburgh, UK)
• Rychard Bouwens (Leiden University, The Netherlands)
• Marusa Bradac (University of Ljubljana Slovenia)
• Andrew Bunker (Oxford University, UK)
• Antonello Calabrò* (INAF, Observatory of Rome, Italy), co-chair
• Stephane Charlot (Institut d'Astrophysique de Paris, France)
• Mirka Dessauges-Zavadsky (University of Geneve, Switzerland)
• David Elbaz (CEA, France)
• Andrea Ferrara (Scuola Normale Superiore di Pisa, Italy)
• Natascha Foerster-Schreiber* (MPE, Germany) co-chair
• Luca Graziani* (Sapienza University of Rome, Italy), co-chair
• Thorsten Naab (MPA, Germany)
• Giulia Rodighiero* (University of Padova, Italy) chair
• Paola Santini (INAF, Observatory of Rome, Italy)
• Sandro Tacchella (Cambridge University, UK)
• Hannah Übler (Cambridge University, UK)

Contact

giulia.rodighiero@unipd.it luca.graziani @ uniroma1.it