Issue |
A&A
Volume 412, Number 1, December II 2003
|
|
---|---|---|
Page(s) | 105 - 120 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20031478 | |
Published online | 25 November 2003 |
Does transparent hidden matter generate optical scintillation?
Laboratoire de l'Accélérateur Linéaire, IN2P3-CNRS, Université de Paris-Sud, BP 34, 91898 Orsay Cedex, France
Corresponding author: moniez@lal.in2p3.fr
Received:
17
February
2003
Accepted:
4
September
2003
Stars twinkle because their light goes through the atmosphere.
The same phenomenon is expected when the light of extra-galactic stars
goes through a Galactic – disk or halo – refractive medium.
Because of the large distances involved here, the length and time
scales of the optical intensity fluctuations resulting from the
wave distortions are accessible to current technology.
In this paper, we discuss the different possible scintillation
regimes and we focus on the so-called strong diffractive regime
that is likely to produce large intensity contrasts.
The critical relationship between the source angular size and the
intensity contrast in optical wavelengths is also
discussed in detail.
We propose to monitor small extra-galactic stars every ~10 s
to search for intensity scintillation produced by molecular hydrogen
clouds.
We discuss means to discriminate such hidden matter
signals from the foreground effects on light propagation.
Appropriate observation of the scintillation process
described here should allow one to detect column density
stochastic variations in Galactic molecular clouds of the order of ~, that is
per ~
transverse distance.
Key words: cosmology: dark matter / Galaxy: disk / Galaxy: halo / ISM: clouds / ISM: molecules
© ESO, 2003
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