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Session 17 - The Galactic Interstellar Gas.
Display session, Monday, January 13
Metropolitan Ballroom,

[17.03] Galactic HI Density Fluctuations on AU and Parsec Scales

A. Minter, F. J. Lockman (NRAO, Green Bank)

Density fluctuations in the galactic neutral hydrogen emission have been observed on scales from \sim 0.2 pc to \sim100 pc via interferometric observations (Crovisier and Dickey, Aamp;A, 1983, 122, 282 and Green, MNRAS, 1993, 262, 327). Crovisier and Dickey, and Green have shown that these fluctuations are described by a power law that is inconsistent with the HI density fluctuations being due to clouds. The observed, extremely small scale (10 AU to 10000 AU) HI fluctuations seen by Frail, et al. (ApJ, 1994, 436, 144), Diamond, et al. (ApJ, 1989, 347, 302) and others are not consistent with this power spectrum.

The determination of the power spectrum by Crovisier and Dickey, and Green, however, do not account for the effects of the primary beam of the individual antennas in the interferometric observations. We present preliminary results of the true power spectrum of galactic HI fluctuations based on the data of Crovisier and Dickey, and Green, once the effects of the primary beam have been removed. It is found that the galactic HI density fluctuations are consistent with a Kolmogorov power spectrum. The extremely small scale HI density fluctuations are compared to the true power spectrum of galactic HI density fluctuations.

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