21 cm Line Study of Large Scale Density Fluctuations in the Taurus Molecular Complex

Abstract

21-cm spectra on a 41 × 31 grid, centered at 1950: RA 04^h30^m; DEC 27^d00^m, at points separated by a true angle of 0.25 degrees, were observed using the Arecibo telescope in October 1985. The identical grid had previously been observed in 13CO by Kleiner and Dickman (1984) with the FCRAO mm wave telescope. In this preliminary analysis we determined autocorrelation functions and power spectra for 21-cm self absorption “intensities”, for a cross passing through the central point. Both arms of the cross, aligned parallel to RA and DEC, show a power spectral peak at a frequency of 0.312 reciprocal degrees, corresponding to a period of 3.2 degrees on the sky. Assuming that the Taurus complex is at a distance of 140 pc, this corresponds to a correlation length of 7.8 pc, which is about a factor of two smaller than the value of 14 pc found by Kleiner and Dickman for 13CO.