간행물
천문학회지 KCI 등재 SCOPUS Journal of The Korean Astronomical Society
- 발행기관 한국천문학회
- 자료유형 학술지
- 간기 반년간
- ISSN 1225-4614 (Print)2288-890X (Online)
- 수록기간 1968 ~ 2024
- 주제분류 자연과학 > 천문학 자연과학 분류의 다른 간행물
- 십진분류KDC 440DDC 520
권호리스트/논문검색
제29권 제S호 (1996년 12월) 178건
61.
1996.12
구독 인증기관·개인회원 무료
Recent high resolution CO observations of normal and starburst galaxies at Owens Valley Millimeter Array are summarized. While normal disk galaxies generally show exponential distribution which follows the optical blue light, starburst galaxies are often characterized by a compact (~1 kpc) nuclear complex whose surface gas mass density is strongly correlated with the observed large infrared luminosity and thus the ongoing massive star formation.
62.
1996.12
구독 인증기관 무료, 개인회원 유료
We have studied the response of molecular clouds in the Galactic disk to a rotating bar by conducting Smoothed Particle Hydrodynamics (SPH) simulations for the Galaxy in order to understand the dynamical structures of the Galactic Center (GC) molecular clouds, and their implications. In our study it was found that the structures of GC molecular clouds could be induced by the combined effects of rotating bar potential, the hydrodynamic collisions and gravitational miss collisions between the clouds.
3,000원
63.
1996.12
구독 인증기관·개인회원 무료
A bottom-up model for the formation of GMCs is described, where the observed GMCs are the aggregates of less massive clouds. The aggregates are getting more and more massive in the process of consecutive collision between clouds.
64.
1996.12
구독 인증기관·개인회원 무료
65.
1996.12
구독 인증기관·개인회원 무료
In the past, it. was very difficult to distinguish thermal and non-thermal emission. Broadbent et a1. (1989) has developed a new technique with the help of the IRAS 60 micron emission. The distribution of non-thermal or synchrotron emission in the Galactic disk has been modeled from the 408 MHz all sky survey of Haslam et a1. (1982) after removal of the thermal component.. At. 408 MHz, t.here is very little absorption in the interstellar medium and the distribution along the line-of-sight. is inferred mainly from its presumed relationship to other tracers of spiral structure via a. number of fitted parameters. But. at lower frequencies, free-free absorption becomes important and can give some direct. information on the line of sight. distribution. We have modeled the thermal electron density according to the spiral arm models and the distribution of ionized hydrogen in the Galactic plane by Lockman (1976) and Cersosimo et. al. (1989) and have made predictions to compare with the surveys of Dwarakanath et al. (1990) at. 34.5 MHz and .Jones and Finlay (1974) at 29.9 MHz. The result confirms that the absorption model of the synchrotron emissivity in the Galactic plane is broadly corrected and illustrates the potential of the absorption technique.
66.
1996.12
구독 인증기관·개인회원 무료
H. MATSUHARA, M. TANAKA, M. KAWADA, S. MAKIUTI, T. MATSUMOTO, T. NAKAGAWA, H. OKUDA, H. SHIBAI, N. HIROMOTO, K. OKUMURA, A. E. LANGE, J. J. BOCK
We present the results of an rocket-borne observation of far-infrared [CII] line at 157.7 μm from the diffuse inter-stellar medium in the Ursa Major. We also introduce a part of results on the [CII] emission recently obtained by the IRTS, a liquid-helium cooled 15cm telescope onboard the Space Flyer Unit. From the rocket-borne observation we obtained the cooling rate of the diffuse HI gas due to the [CII] line emission, which is 1.3±0.2 × 10-26 ergss-1 H-1atom. We also observed appreciable [CII] emission from the molecular clouds, with average CII/CO intensity ratio of 420. The IRTS observation provided the [CII] line emission distribution over large area of the sky along great circles crossing the Galactic plane at I = 50° and I = 230°. We found two components in their intensity distributions, one concentrates on the Galactic plane and the another extends over at least 20° in Galactic latitude. We ascribe one component to the emission from the Galactic disk, and the another one to the emission from the local interstellar gas. The [CII] cooling rate of the latter component is 5.6 ± 2.2 ×10.
67.
1996.12
구독 인증기관·개인회원 무료
We have mapped 17 deg2 region toward Galactic anticenter in 12CO J = 1 - 0 using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory (TRAO). The region mapped in this paper is the first target of the Galactic AntiCenter CO Survey Project (GACCOS) and was selected comparing with IRAS Sky Survey Atlas (ISSA) images at 100 μm. Molecular emission of the target area is found to be very extended and is well matching with the FIR emission boundary. There are several pieces of clouds, and as some of spectra show several peaks, there seem to be several clouds overlapped in some directions. The Velocity of Local Standard of Rest (VLSR) of the CO emission of the mapped region ranges from -20 to +10 km/s. It is also found that the two cloudlets located around I = 180° have VLSR = -20 km/s, which is very abnormal. The peak antenna temperature of 13 K arises near the H II Region S241.
68.
1996.12
구독 인증기관·개인회원 무료
69.
1996.12
구독 인증기관·개인회원 무료
70.
1996.12
구독 인증기관·개인회원 무료
The aim of the paper is to analyse the extinction law in the giant H II region NGC 3603. The ratio R is found to be greater than 5.0. In front of the cluster the reddening law is found to be normal. We have obtained a distance of ~5.3 Kpc which is significantly smaller than those adopted so far.
71.
1996.12
구독 인증기관·개인회원 무료
72.
1996.12
구독 인증기관 무료, 개인회원 유료
We report the results of H I 21-cm and molecular line studies of the shocked interstellar gas in the W51 complex. We present convincing evidences suggesting that the shocked gas has been produced by the interaction of the W51C supernova remant (SNR) with a large molecular cloud, Our results show that W51C is the second SNR with direct evidences for the shocked cloud material.
3,000원
73.
1996.12
구독 인증기관·개인회원 무료
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.
74.
1996.12
구독 인증기관 무료, 개인회원 유료
We have made observations of the dark cloud, B5 in the transitions of H2CO, J = 1 10 ― 1 11, and 2 12 ― 1 11. We compared the H2CO result with the observational results of CO and with the visual extinction. There exists an overall correspondence of molecules and extinction. However, a detailed agreement is lacking. We discussed the kinematics and the spatial relationship of molecules and extinction in this cloud.
3,000원
75.
1996.12
구독 인증기관·개인회원 무료
A large scale 13CO(J=1-0) survey was made for CMa OB1/R1 region in 220° ≤ l 230° and -10° ≤ b ≤ 10° with a 8' spacing by using the 4 m radio telescope of Nagoya University. 34 isolated clouds were identified in this survey. Among them, two clouds were firstly identified by us. The observed LSR velocity indicate that almost of the all clouds are located in the Local arm, except two extreme velocity. The mass spectrum of the clouds in the Local arm is best fitted by a power-law index of 1.6.
76.
1996.12
구독 인증기관·개인회원 무료
We observed CO J = 2 → 1 and J = 3 → 2 lines toward several star formation regions with extremely high velocity (EHV) outflows: W3 IRS5, W28 A2, GL2591, S140, and Cepheus A. The full width of the wings are 90-235 km s-1. Some wings show clear break of slope in the line profile implying that the nature of the EHV outflow is different from that of the high velocity outflow. We suggest that the EHV CO wing emission is tracing CO molecules in the stellar wind or jet which drives the high velocity outflow.
77.
1996.12
구독 인증기관·개인회원 무료
We have carried out 13CO J = 1 → 0 line observations with spatial resolution of 2' toward 17 small globules selected from the catalogue of Clemens & Barvainis (1988) with a selection criterion of |b| ≥ 15 degrees using the Nagoya 4-m radio telescope. Overall characteristics and physical parameters are presented and discussed by examining the 13CO integrated intensity map for each of the globules.
78.
1996.12
구독 인증기관·개인회원 무료
79.
1996.12
구독 인증기관 무료, 개인회원 유료
Magnetic fields are thought to playa role in a wide variety of important astrophysical processes, from angular momentum transport and jet formation in accretion disks to corona formation in stars. Unfortunately, the dynamics of magnetic fields in astrophysical plasmas are extremely complicated, and the success of current theoretical models and computer simulations seems to be inversely correlated with the amount of observational detail available to us. Here I will discuss some of the more striking conflicts between numerical simulations and observations, and present an explanation for them based on an important dynamical process which is not adequately modeled in current numerical simulations. These processes will lead to the formation of flux tubes in stars and accretion disks, in accordance with observations. I will discuss some of the implications of flux tube formation for stellar and accretion disk dynamos.
3,000원
80.
1996.12
구독 인증기관 무료, 개인회원 유료
Multi-wavelength observing has been particularly fruitful in cool star research. There have been some well-observed examples, eg AB Dor, though ambiguity remains. This raises issues of data information content and model parameter determinacy, which are examined firstly in an optical context. We then widen the discussion to show how multi-site and multi-wavelength data can be combined to point to better constrained models. Particular cases, involving near-simultaneous radiometry and photometry, are discussed to clarify such modelling.
3,000원
