Letters of Intent received in 2017

LoI 2019-1996
Uncovering early galaxy evolution in the ALMA and JWST era

Topics

1) First light: galaxies at the epoch of reionization
2) Galaxy surveys in the young Universe
3) Advanced methods for spectral energy distribution modelling at high redshift
4) Theoretical models of early galaxy formation and evolution
5) Properties of the interstellar medium at high-redshift
6) Observing the rise of AGN activity and the galaxy-AGN connection
7) Fuelling and quenching of star formation at high redshift
8) Spatially-resolved analyses of galaxies of z>2 galaxies
9) What can we learn from local analogs?

Rationale

Thanks to deep observations in the last few decades with the Hubble Space Telescope, the Spitzer Space Telescope, and ground-based 8-metre class telescopes, we know more about the young Universe than ever before, having reached tantalisingly close to the dark ages and the formation of the first galaxies. It is now well established that the rate of cosmic star formation rose rapidly from the epoch of reionization to a maximum at z~2. The first three billion years of cosmic time were therefore the prime epoch of galaxy formation. Characterising galaxies at this epoch, both observationally and theoretically, is thus crucial to achieve a major goal of modern astrophysics: to understand how galaxies such as our Milky Way have formed and evolved from the primordial density fluctuations in the early Universe.

Many questions remain to be addressed with the next generation of observing facilities and theoretical models. For example, what physical processes drove the rise in star formation rate in the first three billion years? How did black hole growth follow this rise, and how important is the galaxy-AGN connection at early cosmic times? Are galaxies the sole responsible for reionizing the Universe, or are quasars important too? How do the gas, metals and dust in the interstellar medium of early galaxies evolve? What regulates star formation in galaxies, and what are the physical drivers behind the close correlation between stellar mass and star formation rate (the so-called ‘star-forming main sequence’)? Are there different star formation modes associated with secular and interaction-driven starbursts, and how important were those processes in shaping the general galaxy population? What dynamical processes established the morphologies of galaxies we observe today?

Recent major international investments in facilities such as the Atacama Large Millimetre Array (ALMA) and the James Webb Space Telescope (JWST), promise to shed light on these questions. ALMA has been operating since 2011 and has already started changing our view of the distant Universe by detecting dust heated by young star formation and cold molecular gas i.e. the fuel for new star formation, with unprecedented sensitivity and spatial resolution. ALMA gives us an exquisite view into the physical state of the interstellar medium in the young Universe, which is determinant in understanding star formation and feedback. JWST, to be launched in late 2018, will give an essential complementary view of the stellar populations in galaxies at those epochs. It will directly observe young stars radiating in the rest-frame ultraviolet as well as more evolved stars emitting mostly in the optical and near-infrared, and it will access the nebular emission from gas ionised by the young stars and by AGN. Combining ALMA and JWST will be crucial to not only detect, but characterise in detail the physical processes governing galaxy evolution in the young Universe. It is crucial for the extragalactic community to maximize the advancement of knowledge provided by having those facilities simultaneously available during the lifetime of JWST.

This symposium will bring together the community of theoretical and observational experts to show how to make the most of ALMA and JWST synergies in advancing our understanding of galaxy evolution in the young Universe during JWST’s lifetime. The goal is to formulate the key questions that will be answered will ALMA+JWST, and discuss the observational diagnostics and theoretical tools that will be required to address them. To achieve this goal, the symposium will include an overview of the state-of-the-art in observations and theoretical models of high-redshift galaxies, define strategic areas where the overlap between ALMA and JWST will be crucial, and foster exchanges and international collaboration between theorists and observers, as well as astronomers observing in different spectral regions.

This symposium will be timely, since June 2019 is close to the start of full JWST operations. Our scientific organizing committee, detailed below, includes 14 confirmed members so far (12 of which are IAU members), who are world experts actively working on the proposed science topics, and are diverse in terms of gender, seniority level, and geographical location. We are strongly committed to also ensuring the diversity of the invited speakers and symposium participants.
The proposed venue, Viana do Castelo (Portugal), is a charming town that contains all the required facilities to host an international symposium of this kind, is affordable, and easily accessible (less than one hour from the Porto international airport). We will work together with local authorities and companies to secure sponsorships and logistical support such as airport shuttles and accomodation at discounted rates for the symposium participants.

Portugal is a member of the European Southern Observatory (ESO), the European Space Agency (ESA, one of the main JWST partners), and hosts a small but vibrant astronomical community, including the recently-established national research institute for astrophysics (Instituto de Astrofísica e Ciências do Espaço) which includes the Portuguese ALMA Center of Expertise (PACE). Hosting this IAU symposium would enhance the visibility of astronomical research in the country and provide a valuable opportunity for participation by physics and astrophysics students at the universities of Porto and Lisbon. The organisation of this symposium will be supported locally by the Centre for Astrophysics of the University of Porto.
We are committed to science outreach and plan to host associated outreach events that will engage the local community and inspire the next generation of local STEM graduates. Specifically, we will organise an evening of public talks by conference participants and local amateur astronomers, followed by stargazing organized in collaboration with the Porto Planetarium during the symposium week. We are also exploring the possibility to organize a teacher training workshop.

Confirmed SOC members:
Elisabete da Cunha, co-chair (ANU, Australia)
Jacqueline Hodge, co-chair (Leiden Obs., The Netherlands)
Franz Bauer (PUC, Chile)
Gustavo Bruzual (UNAM, Mexico)
Karina Caputi (Univ. Groeningen, The Netherlands)
Romeel Dave (Univ. Edinburgh, UK)
Nicole Nesvadba (IAS Orsay, France)
Masami Ouchi (Univ. Tokyo, Japan)
Roderik Overzier (UFRJ, Brazil)
Laura Pentericci (INAF Roma, Italy)
Alexandra Pope (UMass, USA)
David Sobral (Lancaster Univ., UK)
Kim-Vy Tran (UNSW, Australia)
Fabian Walter (MPIA, Germany)

Confirmed LOC members:
Elisabete da Cunha, co-chair (ANU, Australia)
Carlos Martins, co-chair (IA/CAUP, Portugal)
Elsa Silva, grants manager (IA/CAUP, Portugal)
Manuel Monteiro, webmaster (IA/CAUP, Portugal)