IAU Symposium: IAUS 414 High-z galaxies and Black Holes: The JWST/ALMA/GRAVITY Frontier
11 - 15 October 2027, Puerto Natales, Chile
The study of high-redshift galaxies and their supermassive black holes is experiencing a revolution, driven by a new generation of observatories that resolve the gas, dust, stars, and kinematics of galaxies from the earliest epochs of the Universe — some at redshifts of z = 12–14. With the first years of synergistic ALMA–JWST science now behind us, this symposium brings together the global community to take stock of recent discoveries and chart the path forward.
Supermassive black holes at cosmic dawn
JWST has confirmed quasars powered by SMBHs at z > 6, some exceeding 10⁹ M☉, challenging current formation models. Host galaxies show stellar masses of 10⁹–10¹¹ M☉ and star formation rates up to 1000 M☉/yr, with evidence that SMBHs may grow faster than their hosts at high redshift. VLTI/GRAVITY and its upcoming GRAVITY+ upgrade will probe SMBH environments at parsec scales out to z = 7, providing mass determinations highly complementary to ALMA and JWST data.
Little Red Dots and the early galaxy population
One of JWST's most intriguing discoveries, Little Red Dots (LRDs) are a population of compact galaxies existing 0.6–1.6 billion years after the Big Bang — blue in the UV and red in the optical, lacking X-ray detections and displaying flat infrared spectra. They likely represent either very dusty high-redshift galaxies or dust-enshrouded AGN, and comparing them with simulations and semi-analytic models will be key to placing them within our cosmological paradigm.
Cold gas, dust, and star formation across cosmic time
Celebrating its 10th anniversary, ALMA has transformed our view of cold gas and dust in high-redshift galaxies. Three ALMA Large Programs — ALPINE, REBELS, and CRISTAL — have revealed extended [CII] halos, substantial dust contributing ≳ 30% of the cosmic star formation density up to z ~ 7, and complex morpho-kinematics with only a minority of systems showing rotationally supported disks. New programs including CHAMPS, CONDOR, and PHOENIX are expected to present fresh results at the time of the conference.
Morphology, kinematics, and galaxy assembly
Combined ALMA and JWST observations open an unprecedented window into morpho-kinematic studies of cold and warm gas at z > 4. At these redshifts, accretion is expected to be more chaotic and radial transport timescales shorter, with significant implications for SMBH feedback. Resolved studies of disk properties, dense massive star clusters, and gas motions are revealing the physical mechanisms that shaped galaxies during their formative stages, offering key tests for models of galaxy formation and assembly.
Star clusters and SMBH formation pathways
Observations from JWST, ALMA, Gaia, HST, and Euclid confirm that star formation is an inherently clumpy and clustered process. N-body simulations of dense Nuclear Star Clusters (NSCs) demonstrate that stellar runaway collisions can produce very massive objects (10⁴–10⁶ M☉), a process potentially enhanced by gas-driven dynamical friction and accretion. This pathway is increasingly recognized as a viable channel for early SMBH formation, with growing support from local-Universe observational comparisons.
Theory, simulations, and the road to the ELT
Substantial theoretical effort is dedicated to modeling quasar feedback, chemical enrichment, and early structure formation — with results increasingly confronted against detailed JWST and ALMA data. The ELT, with first light planned for 2028, will deliver near-infrared angular resolutions of ~10 mas using adaptive optics, surpassing JWST and rivaling ALMA in some bands. This symposium is a timely moment to synthesize current results and develop programs for the ELT. Dedicated time will also be given to ALMA2040, a planned upgrade offering 5–10× better line sensitivity and 3–5× finer angular resolution.
Outreach program
The symposium will be accompanied by public talks and presentations aimed at educational institutions in Punta Arenas and Puerto Natales, covering general astronomy outreach as well as highlights from the conference themes — including the discovery of high-redshift galaxies and supermassive black holes with Chilean telescopes.
🌐 Visit the IAUS 414 website
Key Topics
- Current state of black hole formation seed scenarios and their predictions for JWST, ALMA and GRAVITY
- Future prospects to characterize supermassive black holes and probe their formation scenarios with JWST, ALMA, and VLT/GRAVITY
- Multiwavelength observations of high-z galaxies and supermassive black holes
- Black hole growth and their feedback in the high-z Universe, including Eddington-limited & super-Eddington accretion
- Co-evolution of supermassive black holes and their host galaxies
- Impact of feedback from supermassive black hole and stellar driven outflows in high-z galaxies and their impact on their evolution
- Properties of massive stellar clusters in high-z galaxies and their impact on the multi-phase interstellar medium.
Important Dates
- 01/07/2026: Beginning of preregistration
- 31/10/2026: End of preregistration
- 01/11/2026: Opening of abstract submission, registration and grant application
- 05/01/2027: Deadline for abstract submission and travel grant applications
- 15/02/2027: Announcement of successful abstracts/talks/IAU grants
- 30/04/2027: Deadline for registration and fee submission
- 30/05/2027: Announcement of final program
- 15/11/2027: Deadline to submit proceedings for the symposium
Contact
Dominik Schleicher, SOC Co-chair
Coordinating IAU Division
Supporting IAU Division
- Division B (Facilities, Technologies and Data Science)
Scientific Organizing Committee (SOC)
- Manuel Aravena, Universidad Diego Portales, Chile
- Caitlin Casey, University of Texas at Austin, USA
- Andrés Escala, Universidad de Chile, Chile
- Rodrigo Herrera-Camus, Universidad de Concepción, Chile (co-chair)
- Hanae Inami, Hiroshima University, Japan
- Claudia Lagos, University of Western Australia, Australia
- Dominik Schleicher, Sapienza University of Rome, Italy (co-chair)
- Raffaella Schneider, Sapienza University of Rome, Italy
- Taro Shimizu, MPE, Germany
- Dominika Wylezalek, Heidelberg University, Germany
Local Organizing Committee (LOC)
- Manuel Aravena, Universidad Diego Portales, Chile
- Andrés Escala, Universidad de Chile, Chile (co-chair)
- Rodrigo Herrera-Camus, Universidad de Concepción, Chile (co-chair)
- Jorge Gonzalez Lopez, Pontificia Universidad Católica de Chile, Chile