We improved the antenna efficiency of the Taeduk Radio Astronomy Observatory (TRAO) 13.7-m radio telescope by adjusting the antenna panels based on digital photogrammetric measurements. First of all, we measured the surface accuracy of the main reflector of this antenna at three elevation angles of 35°, 45°, and 60°. We performed a total of four sets of the photogrammetric measurements and panel adjustments. When adjusting the panels, we positioned the antenna to the zenith and applied the measured data sets at the elevation of 45°. We found that the antenna surface accuracy has been improved by a factor of ~ 3 times after the final adjustment in comparison with the value before the adjustments. And we also found that the antenna surface accuracy tended to be slightly better at the elevation angles of 35° and 60° than that at the elevation angle of 45°. After the final panel adjustment, the aperture and beam efficiencies of the telescope have has been improved from 35% to 44%, and from 41% to 51%, respectively.

We have estimated the fractal dimension of the molecular clouds associated with the H ΙΙ region Sh 156 in the Outer Galaxy. We selected the 12CO 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 ∼ 1.53 for NP ≥ 40, where P ∝ AD/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.

A survey project of TRAO with the fifteen beam array receiver system is presented. A multibeam array receiver system has been purchased from FCRAO, and is being installed on TRAO 14m telescope. The target region of the survey is from ι=120° ~137°, b=-1°~+1°, and velocity resolution would be 1 km/sec after smoothing from the original resolution of 0.64km s-1in the transition of J = 1-0 of 13CO The survey region is a part of the 12CO Outer Galaxy Survey(OGS), and would be an extension of the Bell Laboratories 13CO Galactic Plane Survey. By combining with the existing 12CO database of the Outer Galaxy Survey, we will derive physical properties of identified molecular clouds and will conduct and statistical analysis of the Outer Galalxy molecular clouds. Reduction process and analysis methods will be introduced.

We have conducted observations toward the molecular cloud associated with the H II region Sh 156 in 13CO(J = 1-0), C18O(J = 1-0), and CS(J = 2 -1) using the TRAO 14 m telescope. Combining with existing 12CO(J = 1- 0) data of the Outer Galaxy Survey, we delineated the physical properties of the cloud. We found that there is a significant sign of interaction between the H II region and the molecular gas. We estimated the masses of the molecular cloud, using three different techniques; the most plausible mass is estimated to be 1.37 X 105M⊙, using a conversion factor of X = 1.9 X 1020cm-2 (K km s-1)-1, and this is similar to virial mass estimate. This implies that the cloud is gravitationally bound and in virial equilibrium even though it is closely associated with the H II region. In addition to existing outflow, we found several MSX and IRAS point sources associated with dense core regions. Thus, more star forming activities other than the existing H II region are also going on in this region.

We have estimated the fractal dimension of the molecular clouds in the Antigalactic Center based on the 12CO (J = 1- 0) and 13CO (J = 1- 0) database obtained using the 14m telescope at Taeduk Radio Astronomy Observatory. Using a developed code within IRAF, we were able to identify slice-clouds, and determined the dispersions of two spatial coordinates as well as perimeters and areas. The fractal dimension of the target region was estimated to be D = 1.34 for low resolution 12CO (J = 1 - 0) database, and D = 1.4 for higher resolution 12CO (J = 1 - 0) and 13CO (J = 1 - 0) database, where P ∝ AD/2. The sampling rate (spatial resolution) of observed data must be an important parameter when estimating fractal dimension. Our database with higher resolution of 1 arcminute, which is corresponding to 0.2 pc at a distance of 1.1 kpc, gives us the same estimate of fractal dimension to that of local dark clouds. Fractal dimension is apparently invariant when varying the threshold temperatures applied to cloud identification. According to the dispersion pattern of longitudes and latitudes of identified slice-clouds, there is no preference of elongation direction.

We have mapped 1 deg2 region toward a high latitude cloud MBM 40 in the J = 1 - 0 transition of 12CO and 13CO, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. We used a high resolution autocorrelator to resolve extremely narrow CO linewidths of the molecular gas. Though the linewidth of the molecular gas is very narrow (FWHP < 1 km s-1), it is found that there is an evident velocity difference between the middle upper part and the lower part of the cloud. Their spectra for both of 12CO and 13CO show blue wings, and the position-velocity map shows clear velocity difference of 0.4 km s-1 between two parts. The mean velocity of the cloud is 3.1 km s-1. It is also found that the linewidths at the blueshifted region are broader than those of the rest of the cloud. We confirmed that the visual extinction is less than 3 magnitude, and the molecular gas is translucent. We discussed three mass estimates, and took a mass of 17 solar masses from CO integrated intensity using a conversion factor 2.3 × 10 20 cm -2 (K km s-1)-1. Spatial coincidence and close morphological similarity is found between the CO emission and dust far-infrared (FIR) emission. The ratio between the 100 f.Lm intensity and CO integrated intensity of MBM 40 is 0.7 (MJy/sr)/(K km s-1), which is larger than those of dark clouds, but much smaller than those of GMCs. The low ratio found for MBM 40 probably results from the absence of internal heating sources, or significant nearby external heating sources.

We present a fast reduction method of survey data obtained using a single-dish radio telescope. Along with a brief review of classical method, a new method of identification and elimination of negative and positive bad channels are introduced using cloud identification code and several IRAF (Image Reduction and Analysis Facility) tasks relating statistics. Removing of several ripple patterns using Fourier Transform is also discussed. It is found that BACKGROUND task within IRAF is very efficient for fitting and subtraction of base-line with varying functions. Cloud identification method along with the possibility of its application for analysis of cloud structure is described, and future data reduction method is discussed.

We conducted a deep CCD observations in V band to obtain stellar density distribution and to determine the distances toward two molecular clouds with anomalous velocity in the Galactic anti-center region. Star count method based on the linear programming technique was applied to the CCD photometric data. We found two prominent peaks at distances of around 1.4 and 2.7 kpc. It is found that the first peak coincides well with stellar density enhancement of B8-A0 stars and the second one with the outer Perseus arm. The effect of the choice of the luminosity function is discussed. The stellar number density distribution is used to derive the distances to the molecular clouds and the visual extinctions caused by the clouds. We found that two molecular clouds are located almost at the same distance of about 1.1 ± 0.1 kpc, and the peak extinctions caused by the clouds are about 2.2 ± 0.3 mag in V band.

We have mapped 1 deg2 region toward a high latitude HII region S73 (l, b) = (37°.69, 44°.55) and associated molecular cloud in 12CO J = 1 - 0, and 13CO J = 1 - 0, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. A high resolution autocorrelator is used to resolve extremely narrow CO linewidths (FWHP < 1 km/s) of the molecular cloud. Though the linewidths are very narrow, it is found that there is systematic velocity gradient in the molecular gas associated with the H II region. Both of 12CO and 13CO averaged spectra are non-gaussian, and there are obvious blue wings in the spectra. It is remarkable that the linewidths at the blueshifted region are broader than those of the rest of the cloud. The CO emission does match well with the dust emission.

We have studied the star forming activities and dust properties of Lynds 1251, a dark cloud located at relatively high galactic latitude. Eleven IRAS point sources identified toward Lynds 1251 are discussed. Estimate of stellar masses, and far-infrared lumnosities of the young stars associated with two prominent IRAS point sources imply that these are T-Tauri stars with masses smaller than 0.3M⊙. The low dust temperature of 27 K and low ratio of FIR emission to hydrogen column density are probably due to the lack of internal heating sources. Presumably two low mass young stars do not have enough energy to heat up the dust and gas associated. The dust heating is dominated by the interstellar heating source, and the weaker interstellar radiation field can explain the exceptionally low dust temperatures found in Lynds 1251. The estimated dust mass of Lynds 1251 is just ~1 M⊙, or about 1/1000 of gas mass, which implies that there must be a substantial amount of colder dust. The infrared flux at 100μm is matching well with 13CO peak temperature, while the 12CO integrated intensity is matching with the boundary of dust emission. Overall, the dust properties of Lynds 1251 is similar to those of normal dark clouds even though it does have star forming activities.

We have mapped the whole extent of a dark cloud Lynds 1251 in the emission of the J=1-0 transitions of 12CO and 13CO using FCRAO's fifteen-beam array receiver in high angular resolution of 50'. We have derived physical parameters of L1251, discussed three different mass estimate techniques, and obtained a large range of mass, 600 to 6,000 M⊙, depending on the techniques. The factor of 10 discrepancy between the virial and LTE masses is much larger than expected based on the uncertainties residing in two methods. The large virial mass may reflect the fact that L1251 is not gravitationally bound system as in the case of dark clouds in solar neighborhood. Two outflows are affecting the dynamics of cloud significantly but not enough to reshape the whole extent of the cloud. The small cloud, 'Stripe', which is apparently connected with main cloud, is not likely to be associated with L1251. The velocity gradient composed on this small cloud may be driven by other unknown sources. It is found that L1251 cloud itself is very quiescent except the two bipolar outflow regions.

We have obtained high angular resolution maps toward a molecular cloud associated with an HII region S287 and studied mainly kinematics of the cloud. The mapped region is 1.5 square degrees of the cloud in the transitions of 12CO and 13CO J=1-0. We have obtained a large range of mass, 1.3×104⊙, to $7.2×104⊙ using three different techniques. The S287 molecular cloud shows a very disturbed feature: velocity field of the cloud is very complicated, and shows several arcs. It is likely that the southern part of cloud is being disrupted by the residing HII region S287 as well as external perturbing sources. In addition to an HII region, five bipolar outflows are also disturbing the molecular gas significantly. The large virial mass and the very disturbed morphology may reflect the fact that the cloud is not gravitationally bound system, as in the case of nearby giant molecular cloud (GMC) G216-2.5. The several arc structure and the filamentary features are possibly driven by external strong stellar winds, and these external perturbing sources may be driving the second generation of star-forming activities on the edges of the S287 molecular cloud.