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- The Korean Astronomical Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-4614 (ISSN : 1225-4614)
1225-4614
- DB구축현황 : 1,227건 (DB Construction : 1,227 Articles)
총 게시글 1,227건
페이지 85/123
841
- LA DAIL
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.83-91
- 1996
- 원문 바로보기
We present a model that rotating primordial blackholes(PBHs) produced at the end of inflation generate the random, non-oriented primordial magnetic field. PBHs are copiously produced as the Universe completes the cosmic phase transition via bubble nucleation and tunneling processes in the extended inflation hypothesis. The PBHs produced acquire angular momentum through the mutual tidal gravitational interaction. For PBHs of mass less than 1013g, one can show that the evaporation (photon) luminosity of PBHs exceeds the Eddington limit. Thus throughout the lifetime of the rotating PBH, radiation flow from the central blackhole along the Kerr-geodesic exerts torque to ambient plasma. In the process similar to the Bierman's battery mechanism electron current reaching up to the horizon scale is induced. For PBHs of Grand Unified Theories extended inflation with the symmetry breaking temperature of <TEX>$T_{GUT}\;\~\;10^{10}$</TEX> GeV, which evaporate near decoupling, we find that they generate random, non-oriented magnetic fields of <TEX>$\~10^{-11}G$</TEX> on the last-scattering surface on (the present comoving) scales of <TEX>$\~O(10)Mpc$</TEX>.
842
- SUNG EON-CHANG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.87-88
- 1996
- 원문 바로보기
843
- HUANG KELIANG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.105-106
- 1996
- 원문 바로보기
In this paper, we present observations of absorption line spectrum of QSO 1225+317 with resolution of 18 km <TEX>$sec^{-1}$</TEX>. Four possible new heavy element line systems are identified. The properties of Lyman <TEX>$\alpha$</TEX> forest lines are discussed.
844
- TOHMURA ICHIROH
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.321-322
- 1996
- 원문 바로보기
Using the data on the occurrences of the Ho: and soft X-ray flares for the time interval of January 1, 1986-May :31, 1994, we have studied the middle term(30-300days) pericities of the solar flare production during the activity cycle 22. Power analysis of the time seies of daily H<TEX>$\alpha$</TEX> flare index in the northern hemisphere shows prominent periodicities at 220, 120, 109, and 92 days(see Figures l(a) and l(b)), while in the southern hemisphere, those at 267, 213, 183, 167, and 107 days are apparent, though their peaks are not so distint as those in the northern hemisphere. Periodogram of daily soft X-ray flare index also reveal the periodicities at 279, 205, 164, 117, and 91 days in the northern hemisphere, and at 266, 220, 199, 162, 120, and 100 days in the southern hemisphere. Howeer, the 155-day periodicity reported for the earlier cycles, 19, 20, and 21, could not be confirmed in our analysis. to be submitted to Solar Physics; an extended abstract.
845
- BABADZHANOV P. B.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.359-361
- 1996
- 원문 바로보기
846
- CHANG KYONG-AE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.1
- pp.1-8
- 1996
- 원문 바로보기
When we follow the lines of the trajectory of photons which intersect the circle, the circle may suffer some deformation as approaching to the observer. We consider an infinitesimal light bundle suffering gravitational bending. We examine the deformation of the deflected light bundle due to the gravitational lens. The size of the deformation is expressed in terms of the focal length of the gravitational lens.
847
- LEE H. W.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.249-250
- 1996
- 원문 바로보기
848
- LEE HYUNG MOK
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.195-205
- 1996
- 원문 바로보기
The evolution of the stellar debris after tidal disruption due to the super massive black hole's tidal force is difficult to solve numerically because of the large dynamical range of the problem. We developed an SPH (Smoothed Particle Hydrodynamics) - TVD (Total Variation Diminishing) hybrid code in which the SPH is used to cover a widely spread debris and the TVD is used to compute the stream collision more accurately. While the code in the present form is not sufficient to obtain desired resoultion, it could provide a useful tool in studying the aftermath of the stellar disruption by a massive black hole.
849
- FANG C.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.295-298
- 1996
- 원문 바로보기
Non-LTE calculations, with the non-thermal ionization effects included, indicated that for electron bombardment, the H<TEX>$\alpha$</TEX> line is widely broadened and shows a strong central reversal. Significant enhancements at the line wings of Ly<TEX>$\alpha$</TEX> and Ly<TEX>$\beta$</TEX> are also predicted at the beginning of the impulsive phase of flares. For the proton bombardment, no strong broadening and no large central reversal are expected. However, due to proton-hydrogen charge exchange, the enhancements at the red wings of Ly<TEX>$\alpha$</TEX> and Ly<TEX>$\beta$</TEX> lines at the early impulsive phase of flares are significant. Our results show that the electron beam can also in some cases generate visible and UV continuum emission in white-light flares. However, at the onset phase, a negative flare may appear within several seconds, due to the increase of the H- opacity. Another spectroscopic signature of energetic particles, i.e. the impact polarization of atomic lines, is also mentioned.
850
- PANDEY A. K.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.179-180
- 1996
- 원문 바로보기
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 <TEX>$\~$</TEX>5.3 Kpc which is significantly smaller than those adopted so far.