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
제36권 제2호 (2003년 6월) 5건
1.
2003.06
구독 인증기관 무료, 개인회원 유료
CCD observations in V, I and Hα for NGC 3389 are used to present photometry of 61 HII regions. Their positions, diameters and absolute luminosities have been determined. The luminosity and size distribution functions of the HII regions in NGC 3389 are discussed.
4,000원
2.
2003.06
구독 인증기관 무료, 개인회원 유료
In Lee, Kang & Byun (2001) the discovery of Raman scattered 6545 A feature was reported in symbiotic stars and the planetary nebula M2-9. The broad emission feature around 6545 A is formed as a result of Raman scattering of He II n = 6 → n = 2 photons by atomic hydrogen. In this paper, we introduce a method to compute the equivalent width of He II ⋋ 1025 line and present an optical spectrum of the symbiotic star RR Telescopii as an example for a detailed illustration. In this spectrum, we pay attention to the broad Hα wings and the Raman scattered He II 6545 feature. The broad Ha wings are also proposed to be formed through Raman scattering of continuum around Lyβ by Lee (2000), and therefore we propose that the equivalent width of the He II ⋋ 1025 emission line is obtained by a simple comparison of the strengths of the 6545 feature and the broad Hα wings. We prepare a template Hα wing profile from continuum radiation around Lyβ with the neutral scattering region that is supposed to be responsible for the formation of Raman scattered He II 6545 feature. Isolation of the 6545 feature that is blended with [N II] ⋋ 6548 is made by using the fact that [N II] ⋋ 6584 is always 3 times stronger than [N II] ⋋ 6548. We also fit the 6545 feature by a Gaussian which has a width 6.4 times that of the He II ⋋ 6527 line. A direct comparison of these two features for RR Tel yields the equivalent width EW Hel025 = 2.3 Å of He II ⋋ 1025 line. Even though this far UV emission line is not directly observable due to heavy interstellar extinction, nearby He II lines such as He II ⋋ 1085 line may be observed using far UV space instruments, which will verify this calculation and hence the origins of various features occurring in spectra around Hα.
4,000원
3.
2003.06
구독 인증기관 무료, 개인회원 유료
We have examined the relationship between the speeds of coronal mass ejections (CMEs) and the GOES X-ray peak fluxes of associated flares. Noting that previous studies were possibly affected by projection effects and random association effects, we have considered two sets of carefully selected CME-flare events: four homologous events and four well-observed limb events. In the respective samples, good correlations are found between the CME speeds and the GOES X-ray peak fluxes of the associated flares. A similarly good correlation is found for all eight events of both samples when the CME speeds of the homologous events are corrected for projection effect. Our results suggest that a close relationship possibly exists between CME kinematics and flaring processes.
4,000원
4.
2003.06
구독 인증기관 무료, 개인회원 유료
The basic objective of helioseismology is to determine the structure and the dynamics of the Sun by analysing the frequency spectrum of the solar oscillations. Accurate frequency measurements provide information that enables us to probe the solar interior structure and the dynamics. Therefore the frequency of the solar oscillation is the most fundamental and important information to be extracted from the solar oscillation observation. This is why many efforts have been put into the development of accurate data analysis techniques, as well as observational efforts. To test one's data analysis method, a realistic artificial data set is essential because the newly suggested method is calibrated with a set of artificial data with predetermined parameters. Therefore, unless test data sets reflect the real solar oscillation data correctly, such a calibration is likely incomplete and a unwanted systematic bias may result in. Unfortunately, however, commonly used artificial data generation algorithms insufficiently accommodate physical properties of the stochastic excitation mechanism. One of reason for this is that it is computaionally very expensive to solve the governing equation directly. In this paper we discuss the nature of solar oscillation excitation and suggest an efficient algorithm to generate the artificial solar oscillation data. We also briefly discuss how the results of this work can be applied in the future studies.
4,000원
5.
2003.06
구독 인증기관·개인회원 무료
Proof correction to the equation in the third paragraph of the DISCUSSION AND CONCLUSION has not been carried faithfully to the published version of the paper. The corrected equation should read ≈ 10 -3 M 8 4/3(N*/10 6 pc-3)(σ/300 km s-l)-l(r/rt) yr-1, where Ms is the mass of the SMBH in units of 10 8 M⊙, σ is the virial velocity of the stars, rt is the tidal radius of the SMBH. This estimates the frequency that a star would pass within a sphere with the radius r from the SMBH, rather than the frequency of the tidal disruption event. Therefore, it increases with the mass of the SMBH. However, the loss cone effect should also be taken into account, which reduces the actual event rate. Here, we adopted a factor of one hundred to consider the deficiency from the isotrophic rate. The authors sincerely regret this error.
