2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009;
Denver, Colorado
Session J4: Merging Galaxies
1:30 PM–3:18 PM,
Sunday, May 3, 2009
Room: Plaza F
Sponsoring
Units:
DAP GGR
Chair: Scott Hughes, Masschusetts Institutue of Technology
Abstract ID: BAPS.2009.APR.J4.1
Abstract: J4.00001 : Gas inflows in galaxy mergers as a key to the pairing, growth and formation of supermassive black holes
1:30 PM–2:06 PM
Preview Abstract
Abstract
Author:
Lucio Mayer
(Institute for Theoretical Physics, University of Zurich)
Galaxy mergers are known to deliver a large fraction of the
interstellar gas of galaxies towards the inner few hundred
parsecs. The large resulting gas concentrations are of paramount
importance to understand the fueling of central supermassive
black holes, and may determine the conditions under
which a pair of such black holes can sink and coalesce at the
center of the merger remnant following a burst of gravitational
waves. However, for a long time direct calculations that model
the gravitational, hydrodynamical and radiative processes
involved had only been able to hint qualitatively at the
phenomenon of gas inflows, mostly due to their limited
resolution in the nuclear region. Here I review the results of
recent state-of-the art simulations performed with some of the
largest parallel supercomputers available which have
allowed to resolve scales of parsecs and below while the mergers
of two galaxies takes place. I will show how the gas brought
towards the central hundred parsecs produces a massive, star
forming nuclear disk which compares well with recent observations
of merger remnants in the nearby Universe. The numerical
simulations demonstrate that a pair of supermassive black holes
embedded in such nuclear disk can bind into
binary on very short timescales, less than a million year.
Whether the binary of supermassive black holes will easily be
able to shrink down to the separation at which loss of energy via
gravitational waves becomes the dominant process eroding its
orbit is still under investigation. Moreover, in another
calculation probing sub-parsec scales in the nuclear disk it is
shown that more than a hundred million solar masses of gas can
be transported to the inner parsec via torques driven by spiral
instabilities. This strongly suggests not only that such disk
torques are responsible for the fueling of supermassive black
holes in galaxy mergers, but also that a massive black hole may
form directly and rapidly from the collapse of a central gas
cloud produced by the inflow. Direct, fast massive black hole
formation may explain why bright quasars are seen to be in place
already less than a billion year after the Big Bang.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.APR.J4.1