Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble

– First fringes in the H band with the IOTA 3 telescopes interferometer by means of an integrated
optics beam combiner (Monnier et al. 2004, Kraus et al. 2005) and first formal demonstration of
single mode guiding at 10 microns in the IODA project (Labadie et al. 2005).
– Creation and development of the Centre Jean-Marie Mariotti (JMMC) with partners (Nice, and
ASHRA). Consecutive creation of the European interferometry Initiative (EII) coupling interferometry
networks of the OPTICON EC I3, and high-level involvement (PI, PSci) in three of its four
JRAs. The goal of JMMC is to develop user-friendly software, and more generally preparation and
advice, for the use and promotion of the VLTI. (See Appendix in chapter 20
• Sherpa
– Transport of cosmic rays in chaotic magnetic fields. The knowledge of the diffusion coefficients of
cosmic rays is crucial for astrophysical applications and especially for astroparticle physics, both
for mastering the cosmic ray propagation and the efficiency of Fermi acceleration. They have been
computed with a Monte Carlo simulation as a function of the cosmic ray rigidity and the spectrum
of the magnetic field (characterized by its index and its degree of irregularities). It is found that
the transverse diffusion coefficient follows a law which is nor Bohm nor quasi-linear, but a law that
stems from the analysis of the spatial chaos of field lines. This result is important to estimate the
confinement time of cosmic-rays in galaxies and in extragalactic jets (Casse et al. 2002).
– Stationary accretion disks launching super-fast-magnetosonic waves. This is the last paper in the
series on Magnetized Accretion-Ejection Structures (MAES), which represents the only available
self-consistent model of a self-confined jet driven by an accretion disk (with the disk fully resolved),
able to cross all three MHD critical points. Biases induced by the self-similarity contraints are
discussed (Ferreira & Casse 2004).
– On the relevance of subcritical turbulence to accretion disk transport. This paper solves a riddle
dating back to the seventies, and which has given rise to an important controversy in the last ten
years. Namely, it is shown that a linearly stable, keplerian hydrodynamic flow is indeed turbulent
through non linear mechanisms, but that this turbulence has a low efficiency in terms of angular
momentum transport, with a Shakura-Sunyaev parameter α < 10 −5 . The discrepancy between
numerical simulations and laboratory experiments is explained away (Lesur & Longaretti 2005).
– The bulk Lorentz factor crisis of TeV Blazars: evidence for an inhomogeneous pile-up energy distribution.
It is shown that the theoretical Lorentz factors of Blazar jets are contradicted by the
source statistics which implies Lorentz factors of order 3, whereas homogeneous models require 50 or
more. The only way out of this conundrum is to take the jet stratification into account, so that high
energy photons are not produced in the same region as low energy ones. Observations then require
mono-energetic distribution functions whereas most models make use of power-law distributions. In
contradistinction with the dominant view, this work shows that (1) jets do not need to be highly
relativistic, and (2) turbulence rather than shocks is at the origin of the production of high energy
particles (Henri & Saugé 2005).
1.2 Bibliography
A major innovation is the creation of an automated bibliography.
Visit http://www-laog.obs.ujf-grenoble.fr/Laog/publications.php. The principle is that, once a list of
names (LAOG personnel, evolving if necessary) is provided, an automated request is sent to ADS every week.
Thus, new publications (including ArXiv preprints) are regularly added to the bibliographical database. It is
recognized that ADS does not cover all publications (for instance it does not access chemistry journals or some
conferences), so that manual corrections and updates are still necessary, which is done under the responsibility of
the LAOG authors. While this innovation (partly outsourced to a private software company) was implemented
for the present Evaluation exercise, it is a long-term investment and an extremely useful tool that can be
improved in the future (new names, new databases consulted, etc.).
The major quantitative results emerging from the 2001-2005 report bibliography, available in a separate
printed document are as follows: 2
2 The bibliography to be used for the present report (covering the period 2001-2005) is however not exactly identical to the web
bibliography. In particular, care has been taken to weed out refereed papers of LAOG members before their arrival or after their
27