IAP Colloquium の案内が来た。
XXIst IAP Colloquium
MASS PROFILES & SHAPES OF COSMOLOGICAL STRUCTURES
4-9 July 2005
Institut d'Astrophysique de Paris
Scientific Organizing Committee
M. Arnaud (Saclay) J. Binney (Oxford)
F. Combes (Paris) A. Dekel (Jerusalem)
C. Deffayet (IAP) B. Fort (IAP)
H. Hoekstra (Victoria) T. Jacobson (Maryland)
A. Klypin (New Mexico) D. Koo (Santa Cruz)
J. Makino (Tokyo) G. Mamon (IAP, chair)
M. Mateo (Michigan) S. McGaugh (Maryland)
J. Primack (Santa Cruz) R. Sanders (Groningen)
S. White (Munich)
See info and register at
http://www.iap.fr/col2005/
Gary Mamon
Francoise Combes
Bernard Fort
Cedric Deffayet
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The new century has brought two fundamental advances in astrophysics
that are the discoveries of the accelerated expansion of the Universe
with type Ia supernovae, as well as of the flatness of the Universe with
the analysis of the angular fluctuations of the cosmic microwave
background. These two discoveries, together with old results on the
internal kinematics of structures and new results on the statistics of
the large-scale distribution and kinematics of galaxies and weak
gravitational lensing effects on galaxy shapes have enabled cosmologists
to converge towards a concordance model, called LCDM, which describes
with surprising success the large-scale properties of the Universe.
However, the LCDM Universe is mainly built upon two entities of which we
do not know the physical nature: dark matter and dark energy. Moreover,
there seems to be significant discrepancies with several smaller-scale
observations: in particular, in comparison to observational data,
structures arising in very large N-body simulations of the LCDM
Universe appear to be too cuspy in their centres and contain too many
sub-structures. These difficulties have generated a lot of interest in
theories that modify the behaviour of gravity on large scales, e.g. MOND
is able to explain with remarkable success the majority of observational
constraints on mass profiles, without recourse to any dark matter.
Is it then time to reconsider LCDM because of discrepancies with
observations on small scales? Several of these discrepancies are lifted
in very recent modellings of mass profiles and shapes of cosmological
structures using various techniques, such as the internal kinematics of
structures assumed to be in dynamical equilibrium, a similar hydrostatic
analysis of X-ray emitting hot gas, as well as the modelling of
gravitational lenses. Moreover, several recent cosmological N-body
simulations converge towards structures that may be less cuspy in their
centres and contain less sub-structure. Conversely, alternative theories
of gravitation manage to reproduce increasingly well the observational
constraints, and there has been recent progress on building a
theoretical foundation for MOND. Morever, there is a growing interest,
in the theoretical physics community, for theories where gravity is
modified at large distance, with the aim at addressing the dark matter
and dark energy puzzles.
We propose a synthesis of ongoing research on the distribution of matter
in galaxies and clusters of galaxies. Many questions need answers: Have
the cosmological simulations converged or must one increase much more
the number of simulated particles? Is there agreement on the mass
profiles obtained through different modelling techniques and with the
predictions of LCDM simulations? Is mass distribution in quasi-spherical
manner or is it highly flattened? What fraction of mass is in diffuse
form, in between structures? What are the effects of including gas
physics on the mass profiles? Can alternative theories explain the full
set of observational data and how robust are their theoretical general
relativistic foundations? What new key observations need to be realized
to constrain much better these alternative theories?
In this context where ideas are rapidly evolving, it seems most useful
to bring together simulators, observation modellers and gravitational
theorists, with the aim of mixing these three communities to converge in
our understanding of the mass distribution in cosmic structures. Our
objective is to know whether the concordance LCDM model remains
realistic or whether the laws of gravity need to be modified to account
for the existence of dark matter (and possibly explain at the same time
the need for a cosmological constant).
というか、よくみるまでもなく私 SOC なのね。AMR な人も参加のほうよろしく。
)。
