290 research outputs found
Search for hidden turbulent gas through interstellar scintillation
Stars twinkle because their light propagates through the atmosphere. The same
phenomenon is expected when the light of remote stars crosses a Galactic - disk
or halo - refractive medium such as a molecular cloud. We present the promising
results of a test performed with the ESO-NTT and the perspectives of detection.Comment: Structure and dynamics of disk galaxies, Petit Jean Mountain : United
States (2013). arXiv admin note: substantial text overlap with
arXiv:1208.637
Study of a Strategy for Parallax Microlensing Detection Towards the Magellanic Clouds
In this article, we have investigated the possibility to distinguish between
different galactic models through the microlensing parallax studies. We show
that a systematic search for parallax effects can be done using the currently
running alert systems and complementary photometric telescopes, to distinguish
between different lens distance distributions. We have considered two galactic
dark compact objects distributions, with total optical depths corresponding to
the EROS current upper limits. These models correspond to two extreme
hypothesis on a three component galactic structure made of a thin disc, a thick
disc, and a spherically symmetric halo. Our study shows that for sub-solar mass
lenses, an exposure of staryr toward LMC should allow to
distinguish between these two extreme models. In addition the self-lensing
hypothesis (lensing by LMC objects) can efficiently be tested through the
method proposed here.Comment: 10 pages, 12 eps figures. To be published in A&A (accepted version).
Minor changes: - Discussion added on the differential velocity of the thick
galactic disk with respect to the thin disk. - Quality and lisibility of
figures improved. - Typo errors correcte
Search for Turbulent Gas through Interstellar Scintillation
Stars twinkle because their light propagates through the atmosphere. The same
phenomenon is expected when the light of remote stars crosses a Galactic - disk
or halo - refractive medium such as a molecular cloud.We present the promising
results of a test performed with the ESO-NTT and the perspectives.Comment: Tenth Symposium on Sources and Detection of Dark Matter and Dark
Energy in the Universe, Los-Angeles : \'Etats-Unis (2012
Dynamics of inflationary cosmology in TVSD model
Within the framework of a model Universe with time variable space dimensions
(TVSD), known as decrumpling or TVSD model, we study TVSD chaotic inflation and
obtain dynamics of the inflaton, scale factor and spatial dimension. We also
study the quantum fluctuations of the inflaton field and obtain the spectral
index and its running in this model. Two classes of examples have been studied
and comparisons made with the standard slow-roll formulae. We compare our
results with the recent Wilkinson Microwave Anisotropy Probe (WMAP) data.Comment: 18 pages, 3 figures, accepted in Mod. Phys. Lett.
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