恒星大气的连续吸收系数

本文指出,在恒星大气连续吸收系数的计算中,用最丰富元素的每个粒子的连续吸收系数a_c(T,lgp_e)代替通常用的每克物质的连续吸收系数是有益的。本文所考虑的连续不透明度源为:(一)H~-,HI,H_2~-,H_2~ ,He~-,HeⅠ,HeⅡ,CⅠ,CⅡ,CⅢ,NⅠ,NⅡ,NⅢ,OⅠ,OⅡ,NaⅠ,MgⅠ,MgⅡ,AlⅠ,AlⅡ,SiⅠ,SiⅡ,ClⅠ,KⅠ,CaⅡ的吸收。(二)HⅠ,HeⅠ,CⅠ,NI,OI,H_2的瑞利散射。(三)自由电子的汤姆逊散射。最后对太阳光球型大气(见表3),计算了以一个氢粒子为单位的连续吸收系数a_c(T,lgP_e)。     

A broad absorption line outflow associated with the broad emission line region in the quasar SDSS J075133.35+134548.3

We report on the discovery of unusual broad absorption lines(BALs)in the bright quasar SDSS J075133.35+134548.3 at z~1,using archival and newly obtained optical and NIR spectroscopic data.The BALs are detected reliably in HeⅠ*λ3889,HeⅠ*λ10830 and tentatively in AlⅢ,MgⅡ.These BALs show complex velocity structures consisting of two major components:a high-velocity component(HV),with a blueshifted velocity range ofΔv_HV~9300--3500 km s^-1,which can be reliably detected in HeⅠ*λ10830,and tentatively in AlⅢand MgⅡ,whereas it is undetectable in HeⅠ*λ3889;and a low-velocity component(LV),withΔv_LV~3500--1800 km s^-1,is only detected in HeⅠ*λ3889 and HeⅠ*λ10830.With the BALs from different ions,the HV outflowing gas can be constrained to have a density of nH~10^10.3-10^11.4 cm^-3,a column density of NH~10²¹ cm^-2and an ionization parameter of U~10^-1.83-10^-1.72;inferring a distance of RHV~0.5 pc from the central continuum source with a monochromatic luminosityλLλ(5100)=7.0×10⁴⁵erg s^-1at 5100 A.This distance is remarkably similar to that of the normal broad line region(BLR)estimated from reverberation experiments,suggesting association of the BLR and the HV BAL outflowing gas.Interestingly,a blueshifted component is also detected in AlⅢand MgⅡbroad emission lines(BELs),and the AlⅢ/MgⅡof such a BEL component can be reproduced by the physical parameters inferred from the HV BAL gas.The LV BAL gas likely has a larger column density,a higher ionization level and hence a smaller distance than the HV BAL gas.Further spectroscopy with a high S/N ratio and broader wavelength coverage is needed to confirm this to shed new light on the possible connection between BALs and BELs.     

原子配分函数

本文回顾了原子配分函数的计算方法及其结果,用文[2]中的方法计算了原子配分函数。在T=(2000—10000)K,IgP_e=(—3)—(+6)时,LiⅠ,LiⅡ,BeⅠ,BeⅡ,CⅠ,CⅡ,OⅠ,OⅡ,NeⅠ,NeⅡ,NaⅠ和NaⅡ的计算值列在表2—表8中。     

NGC 7538—IRS1致密HⅡ区研究

本文在分析研究NGC7538-IRS1致密HⅡ区H_2CO和OH脉泽辐射VLBI观测结果的基础上,指出该HⅡ区合理的模型是:HⅡ区表面为厚的尘埃层包围,尘埃层两极已被突破,并形成双极流;HⅡ区外面有一个环形转动气体-尘埃云,存在由环向HⅡ区表面的物质下落;包括环和HⅡ区在内的整个系统视向速度为-61km/s,该系统居于视向速度为-57km/s的更大分子云中。H_2CO和OH脉泽发生在HⅡ区两极附近离HⅡ区表面小于0.2R_(HⅡ)的区域内。利用上述模型,还讨论了H_2O脉泽及其他分子吸收线和发射线的发生区域。     

The comparison of H_2CO(1_(10)–1_(11)),C~(18)O(1–0) and the continuum towards molecular clouds

We present large scale observations of C18O(1–0) towards four massive star forming regions: MON R2,S156,DR17/L906 and M17/M18. The transitions of H2CO(110–111),C18O(1–0) and the 6 cm continuum are compared in these four regions. Our analysis of the observations and the results of the Non–LTE model shows that the brightness temperature of the formaldehyde absorption line is strongest in a background continuum temperature range of about 3 – 8 K. The excitation of the H2 CO absorption line is affected by strong background continuum emission. From a comparison of H2 CO and C18 O maps,we found that the extent of H2 CO absorption is broader than that of C18 O emission in the four regions. Except for the DR17 region,the maximum in H2 CO absorption is located at the same position as the C18 O peak. A good correlation between intensities and widths of H2 CO absorption and C18 O emission lines indicates that the H2 CO absorption line can trace the dense,warm regions of a molecular cloud. We find that N(H2CO) is well correlated with N(C18O) in the four regions and that the average ratio of column densities is N(H2CO)/N(C18O) ～ 0.03.     

Unusually Broadened Spectral Profiles Observed in Solar Prominences

After surveying the spectra of 39 prominences observed by the Multichannel Infrared Solar Spectrograph at Purple Mountain Observatory and the 25 cm coronagraph at the Norikura Solar Observatory, we found that about 28% of them show small spatial scale (6"- 8") and short time scale (tens of seconds to a few minutes), unusual large broadening and large shift velocities in spectral lines including Hα, Hβ, Hε, Ca Ⅱ H, Ca Ⅱ K, Ca2Ⅱ 8542 A, He Ⅰ D3 and HeⅠ 10830 A. We present in detail two typical events observed respectively on 2002 May 27 and 1981 August 2. The full-width at half maximum of the widest profile of the 2001 prominence is 1.8 A for Ha and 2.9 A for He I 10830 A, while that of the 1981 prominence is 5.3 A for Hβ, 3.6 A for Ca Ⅱ K, 4.0 A for Ca Ⅱ H and 2.8 A for He Ⅰ D3. Such broadenings generally occur at a level of several-thousand kilometres above the chromosphere. Further, most of these prominences manifest a rotation of (0.4-1.35) ×10-2 rad s-1 pointing to the Sun and large line     

南京大学光谱观测概要(英文)

南京大学太阳塔于1979年在南京郊区建成,1988年参加了全国联测,它的主要性能如下: 定天镜口径:46cm 成象镜口径:33cm 太阳象直径:20cm 多波段光谱仪可观测谱线:H_α,H_β,H_γ,H_(9-12),CaⅡ H, K 光谱观测时间分辨率:～10~s 光谱仪色散度:1.2-1.5mm/A 表1列出了1988年联测期间成功观测到的耀斑光谱(表1见下页)。     

低质量AGB星He壳层内重元素核合成

以^13C（α,n)^16O和^22Ne(α，n）^25Mg作为双脉冲中子源，对于星族Ⅰ低质量AGB星，采用无分叉s-过程反应通道，结合最新恒星深化的计算结果，在各物理参量合理取值范围内，计算了He壳层内重元素核合成。结果表明，渐近分布时所需的脉冲数N0的范围是6－16个，渐近分布达到后，He壳层内重元素的丰度仅与平均中子辐照量τ0有关。与低质量AGB星相应的平均中子辐照量范围是τ0=0.15-1.0mb^-1。     

彗星情报站

新发现的彗星 2004年4月发现了7颗彗星:C／2004 G1(LINEAR),P／2004 EW38 (Catalina-LINEAR),C／2004DZ61 (Catalina-LINEAR),C／2004 H1(LINEAR),P／2004 H2(Larsen),P／2004 H3(Larsen),C／2004 HC18(LINEAR)。情况见下表。     

A catalogue of Hα emission-line point sources in the vicinity fields of M31 and M33 from the LAMOST survey

We present a catalogue of 3305 Hα emission-line point sources observed with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) in the vicinity fields of M31 and M33 during September 2011 and January 2016.The catalogue contains 1487 emission-line stars,532 emission-line nebulae including 377 likely planetary nebulae(PNe),83 H Ⅱ region candidates and 20 possible supernova remnants(SNRs) and 1286 unknown objects.Among them,24 PN candidates,19 H Ⅱ region candidates,10 SNR candidates and one symbiotic star candidate are new discoveries.Radial velocities and fluxes estimated from the Hα line and those quantities of seven other major emission lines including Hβ,[O Ⅲ] A4959,[O Ⅲ] A5007,[N Ⅱ] A6548,[N Ⅱ] A6583,[S Ⅱ] A6717 and [S Ⅱ] A6731 lines of all the catalogued sources yielded from the LAMOST spectra are also presented in our catalogue.Our catalogue is an ideal starting point to study the chemistry properties and kinematics of M 31 and M 33.     

窄线赛弗特Ⅰ星系Markarian478的远紫外成协吸收线(英文)

Markarian 478是典型的窄线赛弗特I星系之一。本文展示了在 2 0 0 1年 1月利用远紫外光谱探测卫星 (FUSE)观测到的Markarian 478的远紫外光谱。我们的光谱覆盖了 91 5Å ;— 1 1 85Å的波长范围 ,分辨率约为 2 0km/s。我们在连续谱上探测到OⅥλλ1 0 3 2 ,1 0 3 8、NⅢλ989和CⅢλ977强发射线。在高电离双线OⅥ以及Lyβ的蓝端线翼上出现了成协吸收线 ,而在NⅢ和CⅢ发射线上没有出现内禀吸收线。这些吸收线被分解成 5个动力学成分 ,它们相对于系统红移zem=0 .0 774的静止坐标系速度覆盖了从 -2 3 0 0～ 3 70km/s的范围     

天体H_2O分子谱线的观测和研究

本文评述了1968年发现天体H_2O分子谱线以来其观测和研究的进展。内容包括(1)天体H_2O脉泽和正常H_2O分子的观测特征;(2)在恒星早期和晚期演化过程中H_2O分子所起的作用和它们可能的状态;(3)利用H_2O分子谱线的观测,研究晚型星拱星包层结构和速度流场、恒星质量损失率以及恒星早期演化过程中的分子云能量平衡等理论研究成果;(4)H_2O脉泽时变特征的观测和研究;(5)银河系天体H_2O(6_(16)-5_(23))脉泽源巡视和H_2O脉泽源星表以及河外H_2O脉泽源的探测。     

OPAL不透明度对恒星结构和演化模型的影响

本文利用国际上最新公布的OPAL不透明度表及相应的化学丰度，计算了三颗不同初始质量的星族互恒星的非守恒演化模型，并和过去长期采用的LAOL不透明度的结果进行详细比较，得出以下主要结论：（1）恒星HR图中的演化轨迹光度降低，主序位置明显向红方向移动；（2）恒星中心H，He燃烧寿命大大延长了；（3）小质量星氢燃烧核和对流核都变小，大、中质量星的中心对流核和燃烧核都有所增大；（4）恒星中心温度－密度关系基本不受影响．     

Ⅰ型塞佛特星系核的光度和质量

利用50个Ⅰ型Seyfert星系的L(H_β)、H_β谱线的零强度宽(FWZI),以及假设吸积物质流模型,求出它们核的质量、热光度和临界光度(Eddington 光度)。发现这样会构成低红移QSO-Ⅰ型Seyfert-Ⅱ型Seyfert的星系核质量分布的序列(图1),Ⅰ型和Ⅱ型Seyfert星系的热光度与临界光度的比值的直方图,也有一个较大的重叠(图2)。再用讫今有的38个Ⅰ型Seyfert星系的X射线光度资料进行统计分析,得到 L_(x(2-10keV))∝M,L_(x(2-10keV))∝(FWZI)~2,利用球吸积模型对结果进行简单的讨论。     

W51M分子云中H和He复合线的观测研究

W51M (W51 Main)是一个和HⅡ区成协的大质量恒星形成区,在其中可以探测到众多的分子谱线和H、He射电复合线.中国科学院上海天文台基于天马65 m望远镜对W51M的观测数据,证认了主量子数在74–117之间的H、He复合发射线,其中主量子数在74–78之间的H和He的α复合线均被探测到.结合H和He复合线的多普勒致宽,算出该HⅡ区的电子温度约为7400 K, He+/H+的离子丰度比约为0.09,这与已有的研究基本吻合.考虑高信噪比的复合线,即H(n)α(74n78),计算得出W51M的平均湍动速度是13.767 km·s-1.通过确定W51M或其他HⅡ区中的复合线,获取电子温度、湍动速度以及其他物理参量,在电子数密度、元素丰度、恒星形成率等方面进行了探讨,对分子谱线以及其他波段的复合线研究具有借鉴意义.     

閃光星(鲸魚UV型星和金牛T型星)

我们在有些恒星上观测到它们的光亮骤然发生变化,例如和太阳隣近的红矮星(鲸鱼UV型)和属於某一星協的星(金牛T型). 本文先列出20颗确定为鲸鱼UV型的星(表1),然後讨论它们的光变情况,如躍变的幅度,光变曲线(表2),闪光的速度(在上昇到极亮时,速度可达0.25星等/秒),躍变的频率等.跟着我们更讨论这些星不在闪光的时候的变化(表3). 这些星的光谱内常有发射线(H与CaⅡ),闪光的时候,光谱上的连续背景加强,并且出现HeⅠ和HeⅡ的谱线,表示温度增加很高,但是这仅限於星的很小的表皮层(1至3％). 鲸鱼UV型星自身亮度很弱(M_(pg)13),数目很多,属星族Ⅰ. 本文内提到几颗御夫RW型星的迅速变化,并且讨论了金牛区(表5),猎户星雲区(表6)和NGC2264里(表7)的闪光星. 我们研究了光变的情况,特别说明鲸鱼UV型星和金牛T型星之间的关系:例如在光曲线、光谱型和同属星族Ⅰ几个方面.我们也讨论了这两型星在绝对星等、光谱和赫-罗图上的位置三者的差异. 最後我们断定鲸鱼UV型星和金牛T型星实在是相同的一群;我们由观测得到的它们之间的差异,其原因一则由於“观测上的选择性”,再则由於这两型星的演化阶段有所不同. 许多恒星的光亮表现突然的增加,或者说很迅速地发出“闪光”,在几分钟、有时在几秒钟内,星光有显著的增加,跟着变暗,初迅速而渐缓慢. 这种星光的躍变在许多型星都观测到,特别是在绝对亮度微弱的星上面.我们现在只讨论下列的主要两类恒星:     

类星体SDSS J2220+0109中特殊吸收线系统的发现与研究

斯隆数字巡天光谱数据中发现,类星体SDSS J2220+0109光谱中同时出现如下极为罕见的吸收线:氢巴尔末线Hα和Hβ,亚稳态He I* λλ3889、3189tt,CaⅡH、K,以及来自FeⅡ*能级的波数分别为7 955 cm~(-1)、13 474 cm~(-1)和13 673 cm~(-1)的众多吸收线.上述吸收线具有相似的速度结构,线宽达1 500 km·s~(-1),相对于发射线表现出蓝移.研究结果表明,这些吸收线很可能来自部分电离区,密度n_E≈10~6cm~(-3),柱密度N_(H I)≈10~(21) cm~(-2),Lyα共振散射对氢原子的激发起重要作用.SDSS J2220+0109斯隆r星等为16.56 mag,是探索活动星系核中特殊吸收线起源的理想实验室.将来的紫外光谱观测可以更加准确决定吸收气体的密度、柱密度、电离参数等物理性质;光学光谱监测有助于限定吸收线的产生机制.此外还发现,SDSS J2220+0109中的FeⅡ发射线显著区别于典型的窄线赛弗特Ⅰ型星系ⅠZw 1,很可能来自低密度气体,进一步研究有助于理解类星体中FeⅡ发射线的起源.     

SDSSJ022119.84＋005628.4： A Radio-Loud Narrow-LineSeyfert 1 Galaxy with Star Formation in its Nucleus

The optical spectrum of SDSS J022119.84 + 005628.4 (R. A. = 02h 21m 19.84s, Dec = 00°56' 28.4", J2000; z = 0.399785 ± 0.000558) is analyzed by multi-component profile modelling. The small flux ratio of [OⅢ]NC/Hβ (=0.78) and FWHM(HβBC) = 1778.1 ±85.9 km s-1 led us to identify SDSS J022119.84 + 005628.4 as a Narrow-line Seyfert 1 galaxy with RFe= 1.4-1.0+1.0 and intermediate radio loudness, logR = 1.93. The continuum low jump at the Balmer limit might be contributed by a starburst component, which suggests that the object is a relatively young AGN with star-formation activity in its inner region. This provides a useful observational test of the AGN evolution. The low flux ratio of the narrow components, [OⅢ]/Hβ = 1.62, and the prominent [OⅡ]γ3727 emission, [OⅡ]/[OⅢ] = 2.24, suggests that there should be a group of AGNs different from Seyfert 2s when their broad line regions are obscured by the torus on the line of sight. A possible orientation effect is suggested to interpret the observed Seyf     

赫歇尔时期下星系中(亚)毫米波谱线发射的研究进展

目前,(亚)毫米波段探测到大量的谱线发射,例如简单分子(如CO,H2O等)的转动发射以及原子(如C,O等)和离子(如C+,N+等)的基态精细结构跃迁.这些谱线是多种物理状态的星际介质(interstellar medium,ISM)的重要冷却剂,可以用于研究气体的物理性质和化学组成以及气体谱线发射的能量来源.首先介绍了...     

On the encounter desorption of hydrogen atoms on an ice mantle

At low temperatures(10 K),hydrogen atoms can diffuse quickly on grain ice mantles and frequently encounter hydrogen molecules,which cover a notable fraction of grain surface.The desorption energy of H atoms on H2 substrates is much less than that on water ice.The H atom encounter desorption mechanism is adopted to study the enhanced desorption of H atoms on H_(2 )substrates.Using a small reaction network,we show that the steady-state surface H abundances predicted by the rate equation model that includes H atom encounter desorption agree reasonably well with the results from the more rigorous microscopic Monte Carlo method.For a full gas-grain model,H atom encounter desorption can reduce surface H abundances.Therefore,if a model adopts the encounter desorption of H atoms,it becomes more difficult for hydrogenation products such as methanol to form,but it is easier for C,O and N atoms to bond with each other on grain surfaces.