Does Transparent Hidden Matter Generate Optical Scintillation?

Abstract

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 the 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 $\sim 10\mathrm{s}$ to search for intensity scintillation produced by molecular hydrogen clouds. We discuss means to discriminate such hidden matter signal 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 order of $\sim 3\times 10^{-5}g/c{\mathrm{m}}^2$, that is $10^{19}molecules/c{\mathrm{m}}^2$ per $\sim 10000\mathrm{km}$ transverse distance.

16 pages, 10 eps figures. Accepted for publication in A&A. Minor changes/additions : temporal coherence aspects; scintillation of a quasar in tables 1 (reorganized) and 4; further details on the Local Interstellar Medium

References in corpus (4)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Preliminary Maps and Basic Results
• FUSE Survey of the Local Interstellar Medium within 200 Parsec
• Comparison of filters for detecting gravitational wave bursts in interferometric detectors
• Does Transparent Hidden Matter Generate Optical Scintillation?

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• Does Transparent Hidden Matter Generate Optical Scintillation?
• Binary microlensing with plasma environment -- Star and planet
• CMB as a possible new tool to study the dark baryons in galaxies
• Searching for Galactic hidden gas through interstellar scintillation: Results from a test with the NTT-SOFI detector
• Simulation of optical interstellar scintillation