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Extragalactic
Astrophysics &
Observational Cosmology Group
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| Tobias
Kaufmann |
Postal
Address:
ETH
Hoenggerberg Campus
Physics Department, HIT J 21.5
CH-8093 Zurich
Switzerland
Phone: +41 44 633 77 25
Fax: +41 44 633 12 38
email:
tobias.kaufmann@phys.ethz.ch
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| Curriculum
Vitae |
Education:
2006
Ph.D
in Theoretical Physics; University of Zurich, Switzerland
2002
dipl.
phys. in Theoretical Physics; University
of
Zurich,
Switzerland
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Employment:
2009 -
SNF
Ambizione
Fellow, Institute
of
Astronomy, ETH Zurich, Switzerland
2009
Postdoctoral
Researcher, University of California,
Irvine, USA
2008
SNF
Postdoctoral
Research
Fellow, University
of
California,
Irvine, USA
2006 - 2007 Postdoctoral
Researcher,
University of California,
Irvine, USA |
Awards:
2009
SNF Ambizione Fellowship, ETH Zurich, Switzerland
2007
SNF Research Fellowship, University
of
California,
Irvine, USA
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| Research
Interests |
Gas cooling and the
formation of galaxies:
Among
the biggest question in galaxy formation is why galaxies have so little
normal matter compared to dark matter. Most researchers believe that
these "missing baryons" are in low-density hot gas (or plasma) between
galaxies and galaxy halos. J. Bullock, L. Mayer, J. Diemand and A.
Maller and I are simulating gas cooling and galaxy formation to
understand these issues. Two of our simulations of a Milky Way Galaxy
from Kaufmann et al. (2009) are shown below, the difference coming only
from the initial entropy profile of the hot gas halo. This work may
help understand the origin of the mysterious High Velocity Clouds that
orbit around the Milky Way Galaxy.
Disk galaxy formation
Forming
galactic disks in a cosmological simulation is a subtle issue. One of
the problems beeing the so-called "angular momentum catastrophe". We
showed in Kaufmann et al. (2007) that the loss of angular momentum in
the cold disk is at least party related to numerics, i.e., missing
resolution. The picture below shows the same simulated galactic disk,
but sampled with increasing resolution (from right to left),
illustrating the numerical angular momentum loss.
At even higher resolution, we were then able to resolve
the clumpy multiphase medium around galactic disks (left figure from
below). The predictions for the rotational velocities above the disk
plane match well H I observations of e.g. NGC 891 (Kaufmann et al.
2006).
 
For
smaller galaxies the same kind of models naturally delivered decreased
starformation efficiency, closely matching
observations. Pressure support becomes more
important in less massive haloes which keeps the galaxy thicker (Plots taken from Kaufmann, Wheeler & Bullock 2007).
 
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Selected
Papers
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- Redistributing hot gas around galaxies:
do cool
clouds
signal a solution to the overcooling Problem?
Kaufmann, T., Bullock, J., Maller, A., Fang, T., Wadsley, J., Monthly
Notices
of the Royal Astronomical
Society (MNRAS), Volume 396, Issue 1, pp. 191-202 (2009).
- On the morphologies, gas fractions, and
star formation rates of small galaxies
Kaufmann, T., Wheeler, C.,
Bullock, J., Monthly
Notices of the Royal Astronomical
Society (MNRAS), Volume 382, Issue 3, pp. 1187-1195 (2007).
- Angular momentum transport and disc
morphology in
smoothed
particle hydrodynamics simulations of galaxy formation
Kaufmann, T., Mayer, L., Wadsley, J., Stadel, J., Moore, B., Monthly
Notices
of the Royal Astronomical
Society (MNRAS), Volume 375, Issue 1, pp. 53-67, (2007).
- Cooling flows within galactic haloes:
the
kinematics and
properties of infalling multiphase gas
Kaufmann, T., Mayer, L.,
Wadsley, J., Stadel,
J., Moore, B Monthly
Notices
of the Royal Astronomical Society (MNRAS), Volume 370, Issue 4,
pp. 1612-1622, (2006).
- ADS link to published
papers.
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