천문학회지 (Journal of The Korean Astronomical Society)

  • 제41권6호
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  • Pages.157-161
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  • 2008
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  • 1225-4614(pISSN)
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  • 2288-890X(eISSN)
한국천문학회 (The Korean Astronomical Society)
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FRACTAL DIMENSIONS OF INTERSTELLAR MEDIUM: II. THE MOLECULAR CLOUDS ASSOCIATED WITH THE HII REGION SH 156

  • 발행 : 2008.12.31
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초록

We have estimated the fractal dimension of the molecular clouds associated with the Hii region Sh 156 in the Outer Galaxy. We selected the $^{12}CO$ cube data from the FCRAO CO Survey of the Outer Galaxy. Using a developed code within IRAF, we identified slice-clouds (2-dimensional clouds in velocity-channel maps) with two threshold temperatures to estimate the fractal dimension. With the threshold temperatures of 1.8 K, and 3 K, we identified 317 slice-clouds and 217 slice-clouds, respectively. There seems to be a turn-over location in fractional dimension slope around NP (area; number of pixel) = 40. The fractal dimensions was estimated to be D = $1.5\;{\sim}\;1.53$ for $NP\;{\geq}\;40$, where $P\;{\propto}\;A^{D/2}$ (P is perimeter and A is area), which is slightly larger than other results. The sampling rate (spatial resolution) of observed data must be an important parameter when estimating fractal dimension. Fractal dimension is apparently invariant when varying the threshold temperatures applied to slice-clouds identification.

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참고문헌

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피인용 문헌

  1. Internal Structure of Stellar Clusters: Geometry of Star Formation vol.6, pp.S270, 2010, https://doi.org/10.1017/S1743921311000214