TY - JOUR
T1 - Balance among gravitational instability, star formation and accretion determines the structure and evolution of disc galaxies
AU - Forbes, John C.
AU - Krumholz, Mark R.
AU - Burkert, Andreas
AU - Dekel, Avishai
PY - 2014/3
Y1 - 2014/3
N2 - Over the past 10 Gyr, star-forming galaxies have changed dramatically, from clumpy and gas rich, to rather quiescent stellar-dominated discs with specific star formation rates lower by factors of a few tens.We present a general theoretical model for how this transition occurs, and what physical processes drive it, making use of 1D axisymmetric thin disc simulations with an improved version of the Gravitational Instability-Dominated Galaxy Evolution Tool (GIDGET) code. We show that at every radius galaxies tend to be in a slowly evolving equilibrium state wherein new accretion is balanced by star formation, galactic winds and radial transport of gas through the disc by gravitational instability-driven torques. The gas surface density profile is determined by which of these terms are in balance at a given radius - direct accretion is balanced by star formation and galactic winds near galactic centres, and by transport at larger radii. We predict that galaxies undergo a smooth transition from a violent disc instability phase to secular evolution. This model provides a natural explanation for the high velocity dispersions and large clumps in z ~ 2 galaxies, the growth and subsequent quenching of bulges, and features of the neutral gas profiles of local spiral galaxies.
AB - Over the past 10 Gyr, star-forming galaxies have changed dramatically, from clumpy and gas rich, to rather quiescent stellar-dominated discs with specific star formation rates lower by factors of a few tens.We present a general theoretical model for how this transition occurs, and what physical processes drive it, making use of 1D axisymmetric thin disc simulations with an improved version of the Gravitational Instability-Dominated Galaxy Evolution Tool (GIDGET) code. We show that at every radius galaxies tend to be in a slowly evolving equilibrium state wherein new accretion is balanced by star formation, galactic winds and radial transport of gas through the disc by gravitational instability-driven torques. The gas surface density profile is determined by which of these terms are in balance at a given radius - direct accretion is balanced by star formation and galactic winds near galactic centres, and by transport at larger radii. We predict that galaxies undergo a smooth transition from a violent disc instability phase to secular evolution. This model provides a natural explanation for the high velocity dispersions and large clumps in z ~ 2 galaxies, the growth and subsequent quenching of bulges, and features of the neutral gas profiles of local spiral galaxies.
KW - Galaxies: evolution
KW - Galaxies: ISM
KW - Galaxies: kinematics and dynamics
KW - Galaxies: structure
UR - http://www.scopus.com/inward/record.url?scp=84893418656&partnerID=8YFLogxK
U2 - 10.1093/mnras/stt2294
DO - 10.1093/mnras/stt2294
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AN - SCOPUS:84893418656
SN - 0035-8711
VL - 438
SP - 1552
EP - 1576
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -