Letters of Intent received in 2017

LoI 2019-2006
Galaxy Evolution and Feedback Across Cosmic Time

Topics

Formation and early evolution of galaxies and their supermassive black holes (SMBHs)

Growth of galaxies through gas accretion and mergers in different environments

Evolution of stellar populations, star formation rates, gas content and metallicity in galaxies

Evolution of the Active Galactic Nuclei population over cosmic time

Mechanisms for quenching/fuelling star formation and SMBH accretion

Feeding and Feedback at the smallest scales: broad line region and accretion disk physics

Feedback mechanisms from star formation, SNe and SMBHs and impact on host galaxies

Feeding in dense environments: hot and cold flows, galaxy mergers;

Quenching star formation in dense environments: mechanical AGN feedback, gas stripping, galaxy harassment

Capabilities of new future instruments to study galaxy and SMBH evolution and feedback

Rationale

Abstract/ Goals:
We propose an IAU Symposium to bring together theorists and observers of the relevant physical processes for galaxy formation and evolution. How do galaxies acquire their gas and how efficiently is it transformed into stars? How is the Supermassive Black Hole in the center fuelled? How powerful are the feedback processes that regulate galaxy evolution? How is star formation quenched? Which is the role of the environment? Although these topics have been recently studied and discussed, strong observational constraints are still scarce. Critical assumptions are usually made due to the lack of spatial resolution and panchromatic observations. An IAU Symposium addressing these topics is timely due to the recent availability of new integral field studies of large samples of galaxies, via surveys such as CALIFA, MaNGA and SAMI, surveys with GMOS-IFU and MUSE, and new capabilities such as ALMA and LOFAR, among others, including also UV, X-ray and Gamma-ray observations. These capabilities allow: (1) the observation of different gas phases -- neutral, molecular and ionized; (2) spatially resolving the star formation histories and the feeding and feedback processes at play inside the galaxies; (3) the observation of the effects of the environment and interactions between galaxies and with the intergalactic medium.

Rationale:
The evolution of galaxies are shaped by a number of processes, such as cold gas flows from the cosmic web, star formation episodes and feedback processes from the environment, supernova explosions and supermassive black holes at the center of galaxies. The so-called feeding and feedback processes are now necessary ingredients in galaxy evolution models, not only regulating the growth of the galaxies but also influencing their environment. Low surface brightness observations are revealing that cold gas flows and low-luminosity dwarf galaxies may have played an important role in shaping the present day massive galaxies. Integral-Field spectroscopic surveys such as CALIFA, MaNGA and SAMI are providing spatially resolved studies of the stellar population properties in galaxies allowing the mapping of its formation history and the impact of galaxy wide outflows from Active Galactic Nuclei (AGN) on the host galaxies. Radio jets extending to hundreds of thousands of kpc, their interaction with ambient gas producing X-ray, optical and infrared emission, relic X-ray cavities observed in galaxy clusters, outflows observed in neutral, ionized and molecular gas, are all observed manifestations of these feedback phenomena. Instruments including Gamma-ray and X-ray satellites, the Hubble Space Telescope, integral field spectrographs on 8-10m class telescopes and radio observations, including the Atacama Large Millimeter Array and LOFAR, have been dedicating increasing fractions of their time to observe and characterize these phenomena and constrain the relevant physical mechanisms. New/innovative instruments are also revealing the richness of the low surface brightness Universe in the outskirts of galaxy clusters.

In view of the availability of new instrumentation and new surveys, a coordinated multi-wavelength observational and combined theoretical effort is key to advancement in this field. We thus plan to bring together observers from across the electromagnetic spectrum with theorists to understand the interplay among the environment, different gas phases, star formation, the growth of supermassive black holes and galaxy evolution, from the earliest epochs to the present day Universe.

We shall stimulate the discussion of new projects that should be beginning their execution with the James Webb Telescope. Further detailed studies at low and high redshift will be possible with future, powerful observatories, both on the ground (notably LSST, E-ELT, GMT, and TMT in the optical and infrared and JVLA, SKA, GMRT in the radio) as well as space missions (e.g., James Webb, Euclid, WFIRST, ATHENA, ATLAST, X-ray Surveyor) and we would welcome discussions on capabilities of some of these missions, thus motivating future observations.

Besides targeting the participation of graduate students in the area of extragalactic astrophysics from the whole country -
that do not have frequent access to international conferences due to recent strict financial constraints from our government, we will include a significant outreach activity in the region involving both local high schools and nearby universities. Our Astronomy Department at Universidade Federal do Rio Grande do Sul (UFRGS, ~30,000 students) in Porto Alegre is an important national reference in Extragalactic Astrophysics research and a number of former PhD students have settled as young professors in other similarly large universities in the area, including Universidade Federal de Santa Maria (UFSM) and Universidade Federal de Pelotas (UfPel), that have themselves already a number of graduate students. Another strong nearby group is at Universidade Federal de Santa Catarina (UFSC), Florianópolis, in our neighboring state. PhD and undergraduate students of these institutions will strongly benefit from an IAU Symposium in the south of Brazil, either participating of the Symposium or of the outreach activities. In addition, in the Bento Gonçalves town and in its close vicinity there are also other Colleges, High Schools and Universities that will be targeted for the outreach activities.