IDENTIFICATION CODE OF INTERSTELLAR CLOUDS WITHIN IRAF

  • Lee, Young-Ung (Taeduk Radio Astronomy Observatory Korea Astronomy Observatory) ;
  • Jung, Jae-Hoon (Taeduk Radio Astronomy Observatory Korea Astronomy Observatory) ;
  • Kim, Hyun-Goo (Taeduk Radio Astronomy Observatory Korea Astronomy Observatory)
  • Published : 1997.12.31

Abstract

We present a code which identifies individual clouds in crowded region using IMFORT interface within Image Reduction and Analysis Facility (IRAF). We define a cloud as an object composed of all pixels in longitude, latitude, and velocity that are simply connected and that lie above some threshold temperature. The code searches the whole pixels of the data cube in efficient way to isolate individual clouds. Along with identification of clouds it is designed to estimate their mean values of longitudes, latitudes, and velocities. In addition, a function of generating individual images (or cube data) of identified clouds is added up. We also present identified individual clouds using a $^{12}CO$ survey data cube of Galactic Anticenter Region (Lee et al. 1997) as a test example. We used a threshold temperature of $5\sigma$ rms noise level of the data With a higher threshold temperature, we isolated subclouds of a huge cloud identified originally. As the most important parameter to identify clouds is the threshold value, its effect to the size and velocity dispersion is discussed rigorously.

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