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1968년 ~ 2024년까지 1,211 건의 한국천문학회지를 격월간 확인하실 수 있습니다.
- The Korean Astronomical Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-4614 (ISSN : 1225-4614)
1225-4614
- DB구축현황 : 1,211건 (DB Construction : 1,211 Articles)
총 게시글 1,211건
페이지 50/122
491
- WANG YUN-CHING
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.299-302
- 2005
- 원문 바로보기
Sprites, elves and blue jets are collectively denominated as the upper atmospheric transient luminous events (TLEs). They are recently discovered optical flashes between active thunderstorms and the ionosphere. In this report, a brief introduction to the most important characteristics of TLEs is given. Since 2001, scientists from the National Cheng Kung University have been performing yearly summer campaigns from various locations in Taiwan. The main achievements of their yearly campaign are presented.
492
- KWOK SUN
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.271-278
- 2005
- 원문 바로보기
Athough planetary nebulae (PNe) have been discovered for over 200 years, it was not until 30 years ago that we arrived at a basic understanding of their origin and evolution. Even today, with observations covering the entire electromagnetic spectrum from radio to X-ray, there are still many unanswered questions on their structure and morphology. In this review, we summarize recent theoretical and observational advances in PNe research, and discuss the roles of PNe in the chemical (atomic, molecular, and solid-state) enrichment of the galaxy and as tracers of the large scale structure of the Universe.
493
- CHUNG EUN JUNG
- Journal of the Korean astronomical society = 천문학회지
- 38, n.1
- pp.17-22
- 2005
- 원문 바로보기
In this paper, we suggest a new referencing method for the array On-The-Fly(OTF) observations in radio astronomy. To reduce the baseline residual, we have proposed and evaluated a new referencing method which uses the source free regions in the observed frame as references. These new references have small <TEX>${\Delta}$</TEX>t and <TEX>${\Delta}$</TEX>x, the time and position differences between the source and the references, and the systematic problems w~re improved by using this new referencing method. The curved baseline residuals were straightened and the rms was reduced to 17 mK. This new referencing method is expected not only to make possible to take more stable data for the array OTF observation of external galaxies but also to save the observation and data reduction time.
494
- Kim Sang-Chul
- Journal of the Korean astronomical society = 천문학회지
- 38, n.4
- pp.429-435
- 2005
- 원문 바로보기
We present BV CCD photometry for the open clusters Czernik 24 and Czernik 27. These clusters have never been studied before, and we provide, for the first time, the cluster parameters; reddening, distance, metallicity and age. Czernik 24 is an old open cluster with age <TEX>$1.8{\pm}0.2Gyr$</TEX>, metallicity <TEX>$[Fe/H]=-0.41{\pm}0.15dex$</TEX>, distance modulus <TEX>$(m-M)_0=13.1{\pm}0.3mag$</TEX> (<TEX>$d=4.1{\pm}0.5kpc$</TEX>), and reddening <TEX>$E(B-V)=0.54{\pm}0.12mag$</TEX>. The parameters for Czernik 27 are estimated to be <TEX>$age=0.63{\pm}0.07Gyr$</TEX>, <TEX>$[Fe/H]=-0.02{\pm}0.10dex$</TEX>, <TEX>$(m-M)_0=13.8{\pm}0.2mag$</TEX> (<TEX>$d=5.8{\pm}0.5kpc$</TEX>), and <TEX>$E(B-V)=0.15{\pm}0.05mag$</TEX>. The metallicity and distance values for Czernik 24 are consistent with the relation between the metallicity and the Galactocentric distance of other old open clusters. We find the metallicity gradient of 51 old open clusters including Czernik 24 to be <TEX>${\Delta}[Fe/H]/{\Delta}R_{gc}=-0.064 {\pm}0.009dex\;kpc^{-1}$</TEX>.
495
- ZHOU Xu
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.203-206
- 2005
- 원문 바로보기
The large field multi-color CCD sky survey program based on the 60/90 Schmidt telescope of NAOC has been processed in cooperation among many observatories and universities of Asian countries. The observation and scientific results are reviewed.
496
- Lee, Ho-Gyu
- Journal of the Korean astronomical society = 천문학회지
- 38, n.4
- pp.385-414
- 2005
- 원문 바로보기
We have searched for infrared emission from supernova remnants (SNRs) included in the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) field. At the positions of 100 known SNRs, we made 3.6, 4.5, 5.8, and <TEX>$8.0{\mu}m$</TEX> band images covering the radio continuum emitting area of each remnant. In-depth examinations of four band images based on the radio continuum images of SNRs result in the identification of sixteen infrared SNRs in the GLIMPSE field. Eight SNRs show distinct infrared emission in nearly all the four bands, and the other eight SNRs are visible in more than one band. We present four band images for all identified SNRs, and RGB-color images for the first eight SNRs. These images are the first high resolution (<2') images with comparative resolution of the radio continuum for SNRs detected in the mid-infrared region. The images typically show filamentary emission along the radio enhanced SNR boundaries. Most SNRs are well identified in the 4.5 and <TEX>$5.8{\mu}m$</TEX> bands. We give a brief description of the infrared features of the identified SNRs.
497
- FENG LONG-LONG
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.129-133
- 2005
- 원문 바로보기
The temperature (T) and entropy (S) fields of baryonic gas, or intergalactic medium (IGM), in the ACDM cosmology are analyzed using simulation samples produced by a hybrid cosmological hydrodynamic/N-body code based on the weighted essentially non-oscillatory scheme. We demonstrate that, in the nonlinear regime, the dynamical similarity between the IGM and dark matter will be broken in the presence of strong shocks in the IGM. The heating and entropy production by the shocks breaks the IGM into multiple phases. The multiphase and non-Gaussianity of the IGM field would be helpful to account for the high-temperature and high-entropy gas observed in groups and clusters with low-temperature IGM observed by Ly<TEX>$\alpha$</TEX> forest lines and the intermittency observed by the spikes of quasi-stellar object's absorption spectrum.
498
- KOMIYA ZEN
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.157-160
- 2005
- 원문 바로보기
To constrain the values of the model parameters for the cosmological models involving the time-decaying <TEX>$\Lambda$</TEX> term, we have computed sets of theoretical predictions for the N-m relation of galaxies as well as the CMB angular power spectrum: three types of variation, viz., <TEX>${\Lambda}{\propto} T^{-1},\;a^{-m}$</TEX>, and <TEX>$H^n$</TEX> are thereby assumed following Overduin & Cooperstock (1998), although we concentrate here on the discussion of the results obtained from the first type. Our results for the N-m relation indicate that the observed excess of the galaxy counts N in the faint region beyond the blue apparent magnitude 24 can be reasonably well accounted for with the value of <TEX>${\iota}$</TEX> in the range between 0.2 and 1. Furthermore, a comparison of our computational results of the CMB spectra with the observational data shows that the models with a mild degree of the <TEX>$\Lambda$</TEX> term decay, viz., with the value of <TEX>${\iota}{\le}$</TEX>0.4, are favorable. In this case, the age of our universe turns out to be larger than or equal to 14 Gyr, the lower limit inferred from some Uranium datings.
499
- NISHIOKA HIROAKI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.175-178
- 2005
- 원문 바로보기
We show that next-generation galaxy surveys such as KAOS (the Kilo-Aperture Optical Spectro-graph)will constrain dark energy even if the baryon oscillations are missing from the monopole power spectrum and the bias is scale- and time-dependent KAOS will accurately measure the quadrupole power spectrum which gives the leading anisotropies in the power spectrum in redshift space due to peculiar velocities, the finger of God effect, as well as the Alcock-Paczynski effect. The combination of monopole and quadrupole power spectra powerfully breaks the degeneracy between the bias parameters and dark energy and, in the complete absence of baryon oscillations (<TEX>$\Omega$</TEX>b = 0), leads to a roughly <TEX>$500\%$</TEX> improvement in constraints on dark energy compared with the monopole spectrum alone. As a result, for KAOS the worst case with no oscillations has dark energy errors only mildly degraded relative to the ideal case, providing insurance on the robustness of KAOS constraints on dark energy. We show that nonlinear effects are crucial in correctly evaluating the quadrupole and significantly improving the constraints on dark energy when we allow for multi-parameter scale-dependent bias.
500
- YAO YONGQIANG
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.335-336
- 2005
- 원문 바로보기
The working group for an infrared telescope(IRT) toward East Asian Observatory has been set up in EAMA6. This report declares the membership of IRT working group, reviews briefly the activities of promoting the IRT, and puts forward the future plan.