共查询到20条相似文献，搜索用时 234 毫秒
1.
本利用蒙特卡罗光谱合成方法，对１９９３年由哈勃空间望远镜和里克天台同时得到的超新星１９９３Ｊ的紫外及光学波段的光谱，进行研究并将拟合的结果与别人的模型进行了比较。假设太阳丰度及幂律为２０左右的大气密度结构，模型可以与观测较好地符合。通过计算得到光球速度为９５００ｋｍｓ＾－１左右，光谱的黑体温度为７９９０Ｋ。对于强线如Ｈα及ＨｅＩλ５８７６的特殊谱线轮廓，我们发现大气结构需要是双幂律的，即光球外 相似文献
2.
本文给出用北京天文台２．１６ｍ光学望远镜观测的超新星１９９４Ｉ的光球相光谱。这些光谱表现出类似于Ｉｃ型超新星１９８７Ｍ的特征。我们用蒙特卡罗光谱合成模型对４月１０日的光谱做了拟合。采用Ｎｏｍｏｔｏ等人Ｃ＋Ｏ模型的元素丰度及修改过的Ｗ７密度结构，计算的光谱与观测的光谱符合得相当好。计算得到４月１０日，超新星的光球速度约为１０００ｋｍ／ｓ，其黑体温度约为８０００Ｋ。另外，我们的光谱拟合可以为Ｃ＋Ｏ星作为Ｉｃ型超新星的前身星提供证据。 相似文献
3.
１９８８－１９９２年间，我们用云南天文台１ｍ望远镜的Ｃｏｕｄｅ－ＣＣＤ摄谱仪系统，对大角星的Ｈｅｉ１０８３０Ａ谱线进行了高分辨率光谱观测。从１９９１年６月２日的观测资料中发现谱线中出现明显的发射特征。该谱线显出类似于天鹅座Ｐ型星的轮廓，有发射射 和吸收谷，发射峰的蓝移有相当于６ｋｍ／ｓ的向外速度。分析认为我们观测到的是大角星的一次以天计的短时标色球剧烈活动，它伴随着物质的向外抛射，也引起星周物质的 相似文献
4.
１９８８─１９９２年间，我们用云南天文台１ｍ望远镜的Ｃｏｕｄｅ－ＣＣＤ摄谱仪系统，对大角星的ＨｅＩ１０８３０Ａ谱线进行了高分辨率光谱观测。从１９９１年６月２日的观测资料中发现谱线中出现明显的发射特征。该谱线显现出类似于天鹅座Ｐ型星的轮廓，有发射峰和吸收谷。发射峰的蓝移有相当于６ｋｍ／ｓ的向外速度。分析认为我们观测到的是大角星的一次以天计的短时标色球剧烈活动，它伴随着物质的向外抛射，也引起星周物质的向外运动。 相似文献
5.
通过把从光球辐射出来的连续能谱能量分成大量的光子包，然后用ＭｏｎｇｅＣａｒｌｏ方法跟踪这些光子包从光球向超新星包层外运动的过程，这一方法能很好的解决超新星的光谱拟合中的谱线覆盖问题，由于同时编制了用于构造超新星包层中的密度结构和丰度分布的程序，以及大量的用比较观测和理论拟合的绘图和支持程序，使我们的ＭｏｎｔｅＣａｒｌｏ光谱拟合软件包能够很好的运用于超新星的早期光谱研究。本文给出了ＳＮ１９９３Ｊ在１ 相似文献
6.
用于分子谱线观测的512路数字式自相关频谱仪 总被引：1，自引：0，他引：1
本文简要介绍了采用一比特自相关技术实现的５１２路数字式自相关频谱仪的工作原理及系统的硬件和软件构成。该频谱仪主要用于分米及ｃｍ波段分子谱线观测。频谱仪系统时钟可在６２５ＫＨｚ和２０ＭＨｚ之间按２的倍率选择，最大分析带宽为１０ＭＨｚ。最高频率分辨率为０．６１ＫＨｚ，相应于１８ｃｍ波段的速度分辨率为０．１ｋｍ／ｓ。文章最后给出了利用上海天文台２５ｍ射电望远镜观测ＯＨ脉泽源的结果。 相似文献
7.
1991年日全食近红外光谱观测结果 总被引：1，自引：0，他引：1
介绍１９９１年７月１１日墨西哥日全食的近红外光谱（１０７１２－１０９７２）观测资料和分析结果．从无缝谱得出的极边缘光球连续谱表面亮度曲线上发现在日面边缘之内２１０ｋｍ处有一强度凹陷,由该曲线拐点定出色球底的温度为４４２５±２６°Ｋ．无缝闪光谱资料显示Ｈｅｌ１０８３０线在边缘外１２００ｋｍ附近发射达极大,其下降段的对数梯度β为０．６３３×１０－８ｃｍ－１,与可见区Ｈｅｌ线相近．此外,东边大日珥的资料显示该日珥的强度很弱,仅为普通日珥强度的２％—５％,具有很大的湍流速度（约３０ｋｍ／ｓｅｃ）和视向蓝移运动（２１０±１５ｋｍ／ｓｅｃ）．由于Ｐγ在光谱上没有显示,所以认为其激发程度很高．该资料中未找到非日珥性质的色球发射 相似文献
8.
通过把从光球辐射出来的连续谱能量分成大量的光子包，然后用MonteCarlo方法跟踪这些光子包从光球向超新星包层外运动的过程，这一方法能很好地解决超新星的光谱拟合中的谱线覆盖问题，由于同时编制了用于构造超新星包层中的密度结构和丰度分布的程序，以及大量的用于比较观测和理论拟合的绘图和支持程序，使我们的MonteCarlo光谱拟合软件包能够很好地运用于超新星的早期光谱研究。本文给出了SN1993J在1993年4月13日的观测光谱的运行实例。 相似文献
9.
本文作者首次对暗云Ｌ１２１１的Ｃ~（１８）Ｏ（Ｊ＝１－０）分子发射谱线进行了观测，发现了暗云Ｌ１２１１致密核的Ｃ~（１８）Ｏ（Ｊ＝１－０）的宽翼发射谱线和它的结构，得到了核区Ｃ~（１８）Ｏ（Ｊ＝１－０）分子的谱线轮廓图、强度分布图、速度分段积分等高图、速度位置图。 相似文献
10.
暗云L1211的C^18O（J=1—0）分子发射谱线的观测 总被引：1，自引：1，他引：0
本文作者首次对暗云Ｌ１２１１的Ｃ＾１８Ｏ（Ｊ＝１－０）分子发射谱线进行了观测，发现了暗云Ｌ１２１１致密核的Ｃ＾１８Ｏ（Ｊ＝１－０）的宽翼发射谱线和它的结构，得到了核区Ｃ＾１８Ｏ（Ｊ＝１－０）分子的谱线轮廓图、强度分布图、速度分段积分等高图、速度位置图。 相似文献
11.
R. J. Barber S. Miller N. Dello Russo M. J. Mumma J. Tennyson P. Guio 《Monthly notices of the Royal Astronomical Society》2009,398(3):1593-1600
High-resolution spectra of comet 8P/Tuttle were obtained in the frequency range 3449.0–3462.2 cm−1 on 2008 January 3 ut using CGS4 with echelle grating on United Kingdom Infrared Telescope. In addition to observing solar pumped fluorescent lines of H2 O, the long integration time (152 min on target) enabled eight weaker H2 O features to be assigned, most of which had not previously been identified in cometary spectra. These transitions, which are from higher energy upper states, are similar in character to the so-called SH lines recorded in the post Deep Impact spectrum of comet Tempel 1. We have identified certain characteristics that these lines have in common, and which in addition to helping to define this new class of cometary line give some clues to the physical processes involved in their production. Finally, we derive an H2 O rotational temperature of and a water production rate of (1.4 ± 0.3) × 1028 molecules s−1 . 相似文献
12.
本文对Hewitt＆Burbidge1993年的表中列出的6761颗类星体作进一步的统计分析．全部类星体发射线范围是从0到4．9．统计分析结果表明,平均而言,吸收物质和类星体本身有联系的占46％,各间隔中差异很大,最多的在间隔zem＝0．2－0．3和3．6－3．7中占100％,最少的在0．7－0．8间隔中为零．纵看各图的分布,zem＝2．0的间隔,有明显的突出性,如类星体发射线红移值和吸收线类星体数都在zem＝2为峰值,各间隔中有吸收线≥3条和≥6条的峰值也在zem＝2等． 相似文献
13.
In the framework of the Cerenkov line enission theory we discuss the intrinsic relation between the Cerenkov redshift of HI emission lines of quasars and the line intensity ratio
. Neglecting the contributions of HI recombination lines in the outer optically thin zones of quasars we can use the observed relative shift of the Ly line with respect to the CIV line, i.e., the Cerenkov redshift, to obtain an estimate of the particle population at the 2nd energy level, R2≈ 0.02. We can also use the observed
value to estimate the parameter Xβ ≈ 14.0. For a temperature of 11000 K, the predicted Cerenkov redshifts of HI Balmer lines and the intensity ratio
are then both in good agreement with the observations. This is a strong support for the Cerenkov line emission theory. 相似文献
14.
本文根据文[1，2]三个类星体表的3941个类星体作统计分析，发现在发射红移Zem1．4—3．2范围内吸收线较多，尤其在Zem1．8—2．4范围内明显增加；同时在Zem1．4—2．8范围内出现吸收线红移Zab＞Zem的现象．结果表明，在Zem1．8—2．2间隔内的类星体活动性加剧，似可以说反映了类星体与环境相互作用的演化效应． 相似文献
15.
The asymmetries and Doppler shifts of metallic lines of the 3B flare on September 19, 1979 are investigated in this paper. The results show that: (1) red asymmetries dominate in strong metallic lines, but blue asymmetries also exist in some weak lines; (2) the maximum of the line asymmetry always precedes the maximum of the line intensity; (3) the blue asymmetry occurs generally in the early phase, and can occasionally turn to a red one in the later phase; and (4) the line center has no obvious shift, regardless of the line asymmetry. It is proposed that, the mass motions around the temperature minimum region caused by the impulsive heating or the propagation of the chromospheric condensation can explain these observational results. The study on metallic lines has an auxiliary help for understanding the dynamic process in the lower atmosphere of solar flares. 相似文献
16.
使用4米毫米波望远镜和中澳合作研制的高分辨率声光频谱仪完成了暗星云DC337.7—4.0的CO分子J=1-0谱线的成图观测。数据处理包含有消干扰步骤。获得云的平均辐射温度为7.3K,平均视向速度3.7km/s,平均谱线半宽1.1km/s。观测结果没显示出云中有恒星形成活动的迹象。 相似文献
17.
正负电子湮灭形成的511keV线谱是高能天体物理学光子能谱中的重要成分.本文通过Monte Carlo计算,研究了吸积双星系统(典型的如 CygX-3)中的正负电子湮灭过程.结果表明,一定物理环境下吸积双星系统可以发射较窄的正负电子湮灭线,它的流强和宽度依赖于双星系统发射的高能γ光子的强度大小,X射线晕的状态、尺度和温度分布以及吸积盘中电子的密度大小和分布.本文也讨论了现代的实验(如GRO卫星上的OSSE探测器)观测它的可能性. 相似文献
18.
Zhang Qing Wang Li-fan Hu Jing-yao P. A. Mazzali Wang Zhen-ru 《Chinese Astronomy and Astrophysics》1995,19(4):426-431
We present the modeling of the ultraviolet and optical spectra obtained simultaneously on 1993 April 15 with the HST and at Lick Observatory. A Monte Carlo code is employed in the modeling and a comparison is made between models reported by different groups. With an atmosphere similar to the Sun in chemical composition, the observed spectral lines are well reproduced by a power law density structure of index around 20 except the strong H and HeI λ5876 lines which have peculiar absorption profiles. The photospheric velocity is found to be 9500 km/s and the blackbody temperature of the spectrum is 7990 K. For H and HeI λ5876, we suggest a two-component density structure which has a smoother layer located immediately outside the steeply decreasing inner envelope. The power law indices are most probably 20 and 3, respectively, with the transition point at about 13 000 km/s. In addition, this outer smooth layer serves to flatten the far UV spectrum as observed. 相似文献
19.
As in the first part of the present study (Sapar et al., 2002) we use the β-law for velocity of stellar wind and the Sobolev
approximation for radiative transfer. Here we have succeeded to derive general and relatively simple analytical formulae in
elementary functions for saturated P Cygni type line profiles if parameter 2β is arbitrary positive integer (in the first
part we studied the cases 2β ≤ 4). The four terms obtained describe contributions to the line profile due to isotropic and
anisotropic parts of optical thickness in the source function of the light-scattering layer followed by isotropic and anisotropic
parts of multiple scattering. The limits of acceptability of the Sobolev approximation for β-law have been discussed and specified.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
The availability of new observing facilities both from ground and space such as the Keck 10m telescope and the Hubble Space Telescope is casting new light on the spectroscopic investigation of emission line galaxies. In particular, it is now possible to detect spectra with a significantly improved signal to noise ratio in a very wide wavelength range, from the ultraviolet to the near infrared (HST, Keck) and beyond (ISO is unveiling the far infrared domain). As we move to high redshifts, however, it is more likely that the observed spectra are given by the contribution of different components in the galaxy: in particular, this may be the case if an Active Galactic Nucleus (AGN hereafter) emitting a power-law continuum is surrounded by regions with strong star formation activity. The identification of the source which ionizes the line emitting regions is then complicated by the fact that we are observing the integrated spectrum from regions which are ionized by different sources. In this paper we wish to review which line ratios may be used in order to discriminate between photoionization by young stars and power-law continuum in the wavelength range from 1200 Å to 100 μm. To this aim we used the photoionization code Cloudy (Ferland 1996) to present a series of diagnostic diagrams showing the dependence of emission line ratios on the main input parameters of photoionization models in the case of one component models with gaseous clouds ionized by (1) a stellar continuum typical of an HII region and (2) a power-law continuum typical of an AGN: these line ratios are plotted as isoratio maps for different values of the hydrogen density, ionization parameter and slope of the power-law continuum. We then show how the results may be affected by more realistic assumptions about the environment of the ionized gas: to this aim, we show the effects on selected line ratios of (a) the presence of two populations of clouds with different densities and (b) an AGN surrounded by regions with strong star formation activity. 相似文献