• Title/Summary/Keyword: Clouds

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NEAR-INFRARED HIGH-RESOLUTION SPECTROSCOPY OF THE OBSCURED AGN IRAS 01250+2832

  • Shirahata, M.;Usuda, T.;Oyabu, S.;Nakagawa, T.;Yamamura, I.
    • Publications of The Korean Astronomical Society
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    • v.27 no.4
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    • pp.295-296
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    • 2012
  • We provide a new physical insight on the hot molecular clouds near the nucleus of the heavily obscured AGN IRAS 01250+2832, based on the results of near-infrared high-resolution spectroscopy of gaseous CO ro-vibrational absorption lines with Subaru/IRCS. The detected CO absorption lines up to highly excited rotational levels reveal that hot dense molecular clouds exist around the AGN under the peculiar physical conditions.

Orthogonal projection of points in CAD/CAM applications: an overview

  • Ko, Kwanghee;Sakkalis, Takis
    • Journal of Computational Design and Engineering
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    • v.1 no.2
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    • pp.116-127
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    • 2014
  • This paper aims to review methods for computing orthogonal projection of points onto curves and surfaces, which are given in implicit or parametric form or as point clouds. Special emphasis is place on orthogonal projection onto conics along with reviews on orthogonal projection of points onto curves and surfaces in implicit and parametric form. Except for conics, computation methods are classified into two groups based on the core approaches: iterative and subdivision based. An extension of orthogonal projection of points to orthogonal projection of curves onto surfaces is briefly explored. Next, the discussion continues toward orthogonal projection of points onto point clouds, which spawns a different branch of algorithms in the context of orthogonal projection. The paper concludes with comments on guidance for an appropriate choice of methods for various applications.

Infrared Rainfall Estimates Using the Probability Matching Method Applied to Coincident SSM/I and GMS-5 Data

  • Oh, Hyun-Jong;Sohn, Byung-Ju;Chung, Hyo-Sang
    • Proceedings of the KSRS Conference
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    • 1999.11a
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    • pp.117-121
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    • 1999
  • Relations between GMS-5 infrared brightness temperature with SSM/I retrieved rain rate are determined by a probability matching method similar to Atlas et al. and Crosson et al. For this study, coincident data sets of the GMS-5 infrared measurements and SSM/I data during two summer seasons of 1997 and 1998 are constructed. The cumulative density functions (CDFs) of infrared brightness temperature and rain rate are matched at pairs of two variables which give the same percentile contribution. The method was applied for estimating rain rate on 31 July 1998, examining heavy rainfall estimation of a flash flood event over Mt. Jiri. Results were compared with surface gauge observations run by Korean Meteorological Administration. It was noted that the method produced reasonably good quality of rain estimate, however, there was large area giving false rain due to the anvil type clouds surrounding deep convective clouds. Extensive validation against surface rain observation is currently under investigation.

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DUST SHELL MODELS FOR THE YOUNG STELLAR OBJECTS IN GIANT MOLECULAR CLOUDS

  • Song, In-Ok;Suh, Kyung-Won
    • Journal of Astronomy and Space Sciences
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    • v.17 no.1
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    • pp.11-18
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    • 2000
  • We have modeled the observed spectral energy distributions(SEDs) of young stellar objects (YSOs) in giant molecular clouds (GMCs). We propose the theoretical modles for the dust envelopes around YSOs. The YSOs in a GMC may share the same initial chemical composition. In this paper, we compare the model SEDs with the observations of the YSOs. Dust shells of the YSOs are composed of a mixture of astronomical silicate and graphite grains. We propose the models for the evolution of the GMCs comparing the shape of the SEDs on the IRAS 2-color diagram with the age.

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THE $^{13}CO$ DISTRIBUTION AND CORRELATION WITH EXTINCTION IN L134

  • MINN YOUNG KEY;LEE HYE KYUNG
    • Journal of The Korean Astronomical Society
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    • v.29 no.1
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    • pp.75-81
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    • 1996
  • We mapped the $^{13}CO$ line in the dark nebula L134 using the 14-m Taeduck radio telescope with a 57 arcsec beam and one beam spacing. The cloud has a spherical shape with an intensity peak ridge extended from the northwest to the southeast directions. The halfwidth and the radial velocity of the lines peak at the region of the cloud center. The radial velocity decreases from the cloud center towards the north and south directions. The integrated line intensity distributions in the space-velocity plane show some structure and a velocity gradient. The $^{13}CO$ and $H_2CO$ clouds and dark clouds are closely related in space in shape, outer boundary, and intensity peak positions. The $^{13}CO$ integrated line intensity is linearly proportional to the visual extinction.

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Small scale Structure of Galactic Molecular Clouds toward Continuum Sources by KVN

  • Han, Junghwan;Yun, Young Joo;Park, Yong-Sun
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.2
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    • pp.82-82
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    • 2014
  • One of the subjects in clouds' structure and development is small scale structure of interstellar cloud. The possibility of AU scale structure (Marscher et al. 1993; Moore & Marscher 1995; Roy et al. 2012) is discussed, and this small scale structure is considered as the result of hydrogen volume density (Moore & Marscher 1995), or small-scale chemical and other inhomogeneities (Liszt & Lucas 2000). In order to study this subject with emission line, extremely high resolution is mandatory by VLBI system. However, the alternative method could be observing the absorption line of interstellar cloud on the continuum object. In this case, the resolution would be restricted to the size of the continuum object, if the size of the object is smaller than the resolution of a used telescope. We observed the previous researchers' three objects (BLLAC, NRAO150, B0528+138), whose spectrums are changed from 1993 to 1998 (Liszt & Lucas 2000), with KVN. Through KVN observation, we found the changes of optical depth spectrum compared with the previous spectrums. We will discuss the optical depth spectrum variation by time variation and the meaning of it.

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