Extreme vacuum ultraviolet solar spectra obtained during the SPIRIT experiment aboard CORONAS-F: A catalog of lines in the range 280–330 Å     

I. A. Zhitnik  S. V. Kuzin  A. M. Urnov  I. L. Beigman  S. A. Bozhenkov  I. Yu. Tolstikhina 《Astronomy Letters》2005,31(1):37-56

We present a catalog of 100 lines in the wavelength range 280–330 Å detected by the RES-C spectroheliograph in solar active regions and flares during the SPIRIT experiment aboard the CORONAS-F orbital station. We identified 54 lines. The line intensities recorded during the X3.4 (GOES) solar flare of December 28, 2001, are given. The data reduction procedure is discussed.  相似文献   

The relationship between class I and class II methanol masers     

S. P. Ellingsen 《Monthly notices of the Royal Astronomical Society》2005,359(4):1498-1516

The Australia Telescope National Facility Mopra millimetre telescope has been used to search for 95.1-GHz class I methanol masers towards 62 6.6-GHz class II methanol masers. A total of 26 95.1-GHz masers were detected, 18 of these being new discoveries. Combining the results of this search with observations reported in the literature, a near complete sample of 66 6.6-GHz class II methanol masers has been searched in the 95.1-GHz transition, with detections towards 38 per cent (25 detections; not all of the sources studied in this paper qualify for the complete sample, and some of the sources in the sample were not observed in the present observations).
There is no evidence of an anticorrelation between either the velocity range, or peak flux density of the class I and II transitions, contrary to suggestions from previous studies. The majority of class I methanol maser sources have a velocity range that partly overlaps with the class II maser transitions. The presence of a class I methanol maser associated with a class II maser source is not correlated with the presence (or absence) of main-line OH or water masers. Investigations of the properties of the infrared emission associated with the maser sources shows no significant difference between those class II methanol masers with an associated class I maser and those without. This may be consistent with the hypothesis that the objects responsible for driving class I methanol masers are generally not those that produce main-line OH, water or class II methanol masers.  相似文献   

红外暗云G79.2+0.38的性质     

吴凌翔  杨戟 《天文学报》2005,46(2):136-144

对MSX红外暗云G79.2+0.38的11'×7'的区域范围进行了12CO(1-0)、13CO(1-0)和C18O(1-0)谱线的同时观测.观测到的两个C18O(1-0)谱线所界定的云核峰值分布分别对应MSX A波段的两块高消光区域.该区域的氢分子柱密度N(H2)-(5-12)×1022 cm-2,平均密度n-(3±1)×104cm-3.两块分子云核的13CO的线尺度分别是1.7和1.2 pc,而C18O的线尺度分别是1.2和0.6 pc,它们包含的质量为2×102-2×103M(?).分子云核的视向平均密度结构可用幂函数(?)(p)-p-0.34±0.02表征. 13CO和C18O的丰度和典型的光学暗云相比低了4至11倍,但是目前还没有证据表明13CO和C18O的相对丰度比X13/18随柱密度有显著变化.  相似文献   

A molecular face-on view of the Galactic Centre region   总被引：1，自引：0，他引：1  

Tsuyoshi Sawada  Tetsuo Hasegawa  Toshihiro Handa  R. J. Cohen 《Monthly notices of the Royal Astronomical Society》2004,349(4):1167-1178

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The electron temperature and density in interstellar medium by using carbon radio recombination line observations     

N.I. Rovenskaya 《Astrophysics and Space Science》2004,291(2):113-122

The intensities of carbon radio recombination lines (RRL’s) are definedallowing for the effect of dielectronic-like recombination. The rate ofdielectronic-like recombination is calculated as functions of line number,electron density and temperature accurate to 0.05. Following from the balanceequation solutions for populations, the RRL intensities are analytically foundby the method of successive approximations to an accuracy of 0.15. Theobservations of carbon RRL’s are analyzed toward Cassiopeia A. The averageelectron temperature, density, expanded CII region lengths and inaccuraciesare found with the experimental values of RRL widths and intensities.  相似文献   

Dust obscuration studies along quasar sight-lines using simulated galaxies     

D. K. Churches  A. H. Nelson  M. G. Edmunds 《Monthly notices of the Royal Astronomical Society》2004,347(4):1234-1240

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Visibility of old supernova remnants in H i 21-cm emission line     

Bon-Chul Koo  Ji-hyun Kang 《Monthly notices of the Royal Astronomical Society》2004,349(3):983-993

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Erratum: The spectrum of BAL QSO 03 + 308: intrinsic variability and line-locking stability     

E.Y. Vilkoviskij  M.J. Irwin 《Monthly notices of the Royal Astronomical Society》2001,326(1):416-416

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Profiles of blue and infrared diffuse interstellar bands     

G. A. Galazutdinov  F. A. Musaev  M. R. Schmidt  J. Kre&#;owski 《Monthly notices of the Royal Astronomical Society》2001,323(2):293-300

The paper presents a survey of profiles of reasonably strong diffuse interstellar bands (DIBs) based on the extensive set of high-resolution spectra acquired with the aid of echelle spectrographs installed at the 2-m Terskol, 2-m Pic du Midi and 1-m SAO telescopes. The surveyed diffuse interstellar bands cover the spectral ranges of blue and near-infrared, i.e the DIBs not surveyed by Krełowski & Schmidt . The possible modifications caused by stellar and telluric lines are discussed. The very broad features such as 4430 are not discussed because the shapes of their profiles, extracted from echelle spectra, are very uncertain. The signal-to-noise (S/N) ratios of the spectra are not high enough to enable discussion of the profiles of numerous weak interstellar features discovered recently.  相似文献   

Further constraints on variation of the fine-structure constant from alkali-doublet QSO absorption lines     

M.T. Murphy  J.K. Webb  V.V. Flambaum  J.X. Prochaska  A.M. Wolfe 《Monthly notices of the Royal Astronomical Society》2001,327(4):1237-1243

Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a precise probe for variability of the fine-structure constant, α , over cosmological time-scales. We constrain variation in α in 21 Keck/HIRES Si  iv absorption systems using the alkali-doublet (AD) method in which changes in α are related to changes in the doublet spacing. The precision obtained with the AD method has been increased by a factor of 3:     . We also analyse potential systematic errors in this result. Finally, we compare the AD method with the many-multiplet method, which has achieved an order of magnitude greater precision, and we discuss the future of the AD method.  相似文献