Scientific rationale

 

We live in a fairly stable and peaceful epoch for the Universe, with our Galaxy evolving gently and steadily, forming stars at the relatively modest rate of  ~3 solar masses per year. However, we know that 10 billion years ago the Universe was a significantly more active place, with stars being formed at a 10 times higher rate than it is seen around us today. The mechanisms driving this shutdown of the star formation (SF) activity in galaxies, the so called ’quenching’, remain one of the least understood puzzles in galaxy formation to date. It is well established that the efficiency of a galaxy in forming stars is based on a delicate balance between cold gas inflow and outflow. Several quenching mechanisms have been proposed, which act to either prevent the accretion of new cold material onto the galaxy or remove the gas reservoir from it. In the former case, simulations suggest that the transition from a cold accretion mode in low mass dark matter halos to the hot accretion typical of the most massive halos, naturally leads to the formation of gas-rich star forming galaxies in the field and gas-poor red and dead elliptical in the groups and clusters. In the latter case, instead, powerful outflows, mainly due to the central Black Hole (BH), are advocated as efficient mechanism to expel the gas from the galaxy and stop the star formation. Alternatively, ``morphological quenching'' (MQ) also proposes that the formation of a dominating bulge would lead to the stabilization of the gas against star formation in galactic disks. Which quenching process or which combination of processes is driving the observed shutdown, is still an open question.

The aim of the conference is to challenge the current theoretical framework with the results of the most recent observations and to let theoreticians and observers discuss extensively in order to understand which process is the dominant mechanism for shutting down the SF activity in galaxies or if, instead, a more complex combination of different quenching processes, perhaps efficient at different stellar or halo mass scales, is needed.

 

Key scientific questions addressed by the conference

 

The conference aim is to address the following questions from the observational point of view:

 

• Is there a compelling observational evidence of gas inflow onto galaxies? What is the current view on the galaxy gas content from neutral and molecular gas surveys? Is there a clear relation to the environment?

• What is the interplay between inflow and outflow to set the galaxy gas content and star formation activity?

• Which evidence for quenching are providing the main galaxy scaling relations, such as star forming galaxy Main Sequence, mass-metallicity relation, morphology-density relation? What can we infer about the evolution of the galaxy star formation activity?

• What are the main quenching mechanisms?

• What is the major physical link between morphology, environment, mass and star formation activity?

 

The conference aim is to address the following questions from the theoretical point of view:

 

• What is the role of cold/hot accretion in sustaining/suppressing the SF activity during the structure formation process?

• What is the physics of the galaxy outflow and its effect on the galaxy gas content?

• How are disk instability and compactness driving the morphological evolution of galaxies and their level of star formation activity across cosmic time?

 

Scientific Organizing Committee

 

• Paola Popesso, Excellence Cluster Universe, Garching (cochair)

• Alvio Renzini, Padua Observatory, INAF (cochair)

• Andreas Burkert, Ludwig Maximilliam University München

• Vincenzo Mainieri, European Southern Observatory, Garching

• Andrea Merloni, Max Planck für extraterrestrische Physik, Garching

• Ghazaleh Erfanianfar, Excellence Cluster Universe, Garching

• Klaus Dolag, Ludwig Maximilliam University München

• Celine Peroux, Laboratoire d'Astrophysique de Marseille

• Giulia Rodighiero, Padua Observatory, INAF

• Bianca Poggianti, Padua Observatory, INAF

• Francesca Matteucci, Trieste Observatory, INAF

• Francesco Bertola, Padua Observatory, INAF

 

Local Organizing Commitee

 

• Paola Popesso

• Alvio Renzini

• Sonja Lutz-Lampertseder

• Alice Concas

• Laura Morselli

 

Invited Speakers

 

Review speakers:

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• Avishai Dekel,The Hebrew University of Jerusalem

• Nick Scoville, Caltech

• Filippo Fraternali, University of Bologna

• Joop Schaye, Leiden Observatory

• Nicolas Bouche', Research Institute in Astrophysics and Planetology, Toulouse

• David Elbaz, CEA Saclay,  Service d'Astrophysique

• Roberto Maiolino, University of Cambridge

• Stijn Wuyts, University of Bath

• Arijen van del Wel, Max Planck Institur for Astronomy, Heidelberg

• Frederic Bournaud, CEA Saclay,  Service d'Astrophysique

• Glen Kacprzak, Swinburne University of Technology

• Rachel Somerville, Rutgers University

• Marcella Brusa, University of Bologna

• Andreas Burkert, Ludwig Maximilliam University München

• Adam Muzzin, York University

• Simon Lilly, ETH Zürich

• Bianca Poggianti, INAF, Astronomical Observatory of Padova

• Michele Cirasuolo, European Southern Observatory

• Massimo Stiavelli, Space Telescope Science Institute, Baltimore

• Claudia Maraston, Unversity of Portsmouth

• Tadayuki Kodama, National Astronomical Observatory of Japan, Tokyo

 

Discussion session leaders

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• Marcella Carollo, ETH Zürich

• Gabriella De Lucia, INAF, Astronomical Observatory of Trieste

• Simon Lilly, ETH Zürich

• Nicolas Bouche', Research Institute in Astrophysics and Planetology, Toulouse

• Michele Cappellari, University of Oxford

• Mark Dickinson, NOAO