Letters of Intent for 2015

LoI 2015-190
GA Symposium: The dramatic evolution of galaxy morphology


3 August 2015 to 5 August 2015


XXIX IAU General Assembly, Honolulu, Hawaii, United States


Aaron Robotham (aaron.robotham@uwa.edu.au)

Coordinating division:

Division J Galaxies and Cosmology

Co-Chairs of SOC:

Aaron Robotham (UWA)
Rachel Somerville (Rutgers)
Lisa Kewley (ANU)
Jennifer Lotz (STSCI)
Simon Driver (St Andrews / UWA)

Co-Chairs of LOC:

N/A (GA) ()
N/A (GA) ()
N/A (GA) ()
N/A (GA) ()
N/A (GA) ()



Galaxy morphology
Physical feedback
Galaxy dynamics
Galactic Archeology
AGN fueling
Gas accretion




Feedback has often been discussed in the terms of star formation or colour (i.e. 'quenching'). Stellar orbits, i.e. morphology, are a key component to the larger puzzle, but the main restriction up to and including the Sloan era of surveys has been a lack of high resolution deep data of the kind required for objective analysis of galaxy profiles (morphology, bulge disk decomposition etc). This situation is rapidly changing as major new imaging surveys herald a new era of data across a huge redshift baseline (i.e. VST, VISTA, LSST, DECam, HyperSuprimeCam, Euclid, JWST et al).

Key Science:

Recent data has pointed extra galactic science towards a startling conclusion: galaxies have physically grown and morphologically transformed extremely rapidly over the recent history of the Universe (since z~1). This has been confirmed by independent teams across a broad redshift baseline. At high z this work has involved GEMS, Candels, GOODS, COSMOS, AEGIS, UDS, and at low z this includes SDSS, GAMA and 2MASS. The exact origin of the physics behind this result is still a matter of much debate, and the topic is a fertile area of current research.

There is also exciting work pointing at unique modes of galaxy assembly at the highest redshifts. Recent observational and theoretical work has pointed towards highly chaotic disk instabilities creating complex morphologies in the first galaxies. This issue is particularly important for understanding the role that gas and stellar orbits in galaxies at high redshift have in feeding AGN of SMBH. The AGNs that are formed are believed to have a key role in inhibiting the growth of the first massive galaxies, so reconciling how these first structures transformed mostly into the canonical spheroid at z~0 is a fundamental endeavour.

Symposium Focus:

This symposium will be focused on new observational data related to the evolution of morphology at high and low z, theoretical interpretation of the current results and future surveys that will open the way to new physics. The next generation of instrumentation is moving towards full IFU MOS technology, and in the expectation is that methods for classifying morphology will be entirely overhauled. In this symposium we will determine the questions on morphology evolution that most need answering, and specify the clearest path to answers, with current or future instrumentation.

IAU General Assembly
Honolulu, 3-14 August 2015

IAU General Assembly 2015

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