Updated Inventory of Carbon Monoxide in the Taurus Molecular Cloud

The most extensive survey of carbon monoxide(CO)gas in the Taurus molecular cloud relied on ^(12)CO and ^(13)CO J=1→0 emission only,distinguishing the region where ^(12)CO is detected without ^(13)CO(named mask 1 region)from the one where both are detected(mask 2 region)(Goldsmith et al.2008;Pineda et al.2010).We have taken advantage of recent ^(12)CO J=3→2 James Clerk Maxwell Telescope observations,where they include mask 1regions to estimate density,temperature,and N(CO)with a large velocity gradient model.This represents 1395 pixels out of~1.2 million in the mark 1 region.Compared to Pineda et al.(2010)results and assuming a Tkin of 30 K,we find a higher volume density of molecular hydrogen of 3.3×10^(3) cm^(-3),compared to their 250-700 cm^(-3),and a CO column density of 5.7×10^(15)cm^(-2),about a quarter of their value.The differences are important and show the necessity to observe several CO transitions to better describe the intermediate region between the dense cloud and the diffuse atomic medium.Future observations to extend the ^(12)CO J=3→2 mapping further away from the ^(13)COdetected region comprising mask 1 are needed to revisit our understanding of the diffuse portions of dark clouds.

相干消色散脉冲星观测系统的研究

云南天文台射电天文研究团组利用从美国伯克利大学CASPER天文信号与电子学研究中心购买的现场可编程门阵列(Field-Programmable Gate Array,FPGA)接收机平台ROACH2,实现了512 MHz输入带宽,512 MHz带宽分为128通道输出(每个通道4 M带宽),8比特采样和双极化输入(1 024 MHz)的基带数据采集终端。海量数据传输方式通过SFP+万兆网口实现,利用编写的脚本文件调用DSPSR程序包实现数据的解码、相干消色散、偏振计算和折叠等处理。数据处理结果以PSRFITS格式存储。构建以ROACH2为基带数据采集终端和DSPSR为数据处理核心的脉冲星观测系统,相比于以VLBI观测终端为基础构建的观测系统,在观测模式、数据处理方法、运算效率和观测数据的通用性等方面具有更好的优越性。

新近发现的H_2O6_（16）－5_（23）脉泽速度时变的研究

本文作者用美国ＮＲＡＯ，ＧｒｅｅｎＢａｎｋ４３ｍ和中国科学院紫金山天文台德令哈１３．７ｍ射电望远镜，对新近发现的水６１６—５２３脉泽相隔约１年的三次观测结果作了本地静止标准速度时变的研究，在分析实测结果时采用了参量ＬＳＲ速度延展（Ｖｓｐｄ），相继两历元观测的谱征峰值速度极差（ＤＶ）和速度位移（ＤＶ）．结果表明可将分析样本归纳为两类：Ａ类，微弱多数样本的速度时变给出的谱征位移显示脉泽结的替代效应．这种情况是在观测波束内存在若干未分解的脉泽斑引起的，主要受制于共同激发源的简单运动；Ｂ类，余下的样本给出较大的速度极差，呈现脉泽结整体的运动，涉及激发源的加速和减速以及抽运机制．

新发现的10个恒星形成区的H_2O脉泽源

一、引言目前得到公认的是大多数恒星在它们的最早期的演化中都经历一个非常高能的质量抛射阶段,即出现冷分子气体的大质量双极流。当发现了外流源靠近稠密核时,就认为原恒星体是嵌埋在分子核中。这些外流源看来似乎由恒星风驱动。它们值得注意的其它表现形式包括有高速H_2O脉泽在内的快速移动的HH天体,冲激波激发的分子氢发射区和光子可见喷流等。光学观测提供的实例是最近形成的低质量和中等质量恒星的星风和演化的质量外流阶段现象,射电和红外观测提供的证据是外流可能与大质量星的形成成协,特别是在明亮的嵌埋天体周围发现了高速H_2O脉泽后导致产生这样的看法:很稠密(10~7-10~8cm^(-3)),很紧凑(10-100A.U.)的脉泽'结'(maser'knot')是在强恒星风中被加速到50-100kms^(-1)的,实际上,低光度的H_2O脉泽与HH天体成协说明它们可能是在年轻星周围的外流源中观测到的在不同演化阶段的非常类似的天体。

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 5&Aring ;— 1 1 85&Aring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

Introduction to the Payloads and the Initial Observation Results of Chang'E-1

Chang'E-1,the orbiter circling the moon 200km above the moon surface,is the first Chinese Lunar exploration satellite.The satellite was successfully launched on 24th October 2007.There are 8 kinds of scientific payloads onboard,including the stereo camera,the laser altimeter,the Sagnac-based interferometer image spectrometer,the Gamma ray spectrometer,the X-ray spectrom-eter,the microwave radiometer,the high energy particle detector,the solar wind plasma detector and a supporting payload data management system.Chang'E-1 opened her eyes to look at the moon and took the first batch of lunar pictures after her stereo camera was switched on in 20th November 2007.Henceforth all the instruments are successfully switched on one by one.After a period of parameter adjustment and initial check out,all scientific instruments are now in their normal operating phase.In this paper,the payloads and the initial observation results are introduced.

用软件PSRCHIVE分析脉冲星数据(英文)

PSRCHIVE是一款开源的、面向对象的科学数据分析软件,是一套应用于脉冲星天文学研究的应用包。它通过一系列通用算法实现数据校准与积分、统计分析与模拟以及可视化处理过程,并在脉冲星测时、偏振测量、射频干扰、脉冲变化研究等方面得到了很好的应用。主要概述该软件包含的各种功能,特别是核心应用的各种界面。

Mapping the emission line strengths and kinematics of supernova remnant S147 with extensive LAMOST spectroscopic observations

We present extensive spectroscopic observations of supernova remnant （SNR） S 147 collected with the Large sky Area Multi-Object fiber Spectroscopic Telescope （LAMOST）. The spectra were care- fully sky-subtracted taking into account the complex filamentary structure of S 147. We have utilized all available LAMOST spectra toward S 147, including sky and stellar spectra. By measuring the prominent optical emission lines including Ha, [NII] ）λ 6584 and [S n] λλ6717, 6731, we present maps of radial velocity and line intensity ratio covering the whole nebula of S 147 with unprecedented detail. The maps spatially correlate well with the complex filamentary structure of S147. For the central 2° of S147, the radial velocity varies from - 100 to 100 krn s^-1 and has peaks between - 0 and 10 km s^-1. The intensity ratios of Hα/[S n）λλ6717,6731, [Sn] λ 6717/λ 6731 and Ha/IN Hα/λ 6584 peak at about 0.77, 1.35 and 1.48, respectively, with a scatter of 0.17, 0.19 and 0.37, respectively. The intensity ratios are consistent with the literature values. However, the range of variations of line intensity ratios estimated here, which are representative of the whole nebula, is larger than previously estimated.

Panel positioning error and support mechanism for a 30-m THz radio telescope

A 30-m TeraHertz（THz） radio telescope is proposed to operate at 200 μm with an active primary surface.This paper presents sensitivity analysis of active surface panel positioning errors with optical performance in terms of the Strehl ratio.Based on Ruze＇s surface error theory and using a Monte Carlo simulation,the effects of six rigid panel positioning errors,such as piston,tip,tilt,radial,azimuthal and twist displacements,were directly derived.The optical performance of the telescope was then evaluated using the standard Strehl ratio.We graphically illustrated the various panel error effects by presenting simulations of complete ensembles of full reflector surface errors for the six different rigid panel positioning errors.Study of the panel error sensitivity analysis revealed that the piston error and tilt/tip errors are dominant while the other rigid errors are much less important.Furthermore,as indicated by the results,we conceived of an alternative Master-Slave Concept-based（MSC-based） active surface by implementating a special Series-Parallel Concept-based（SPC-based） hexapod as the active panel support mechanism.A new 30-m active reflector based on the two concepts was demonstrated to achieve correction for all the six rigid panel positioning errors in an economically feasible way.

M-giant star candidates identified in LAMOST DR 1

We perform a discrimination procedure with the spectral index diagram of TiO 5 and Ca H2＋Ca H3 to separate M giants from M dwarfs. Using the M giant spectra identified from LAMOST DR1 with high signal-to-noise ratio, we have successfully assembled a set of M giant templates, which show more reliable spectral features. Combining with the M dwarf/subdwarf templates in Zhong et al., we present an extended library of M-type templates which includes not only M dwarfs with a well-defined temperature and metallicity grid but also M giants with subtypes from M0 to M6. Then, the template-fitting algorithm is used to automatically identify and classify M giant stars from LAMOST DR1. The resulting catalog of M giant stars is cross-matched with 2MASS J H Ks and WISE W1/W2 infrared photometry. In addition, we calculated the heliocentric radial velocity of all M giant stars by using the cross-correlation method with the template spectrum in a zero-velocity rest frame.Using the relationship between the absolute infrared magnitude MJ and our classified spectroscopic subtype, we derived the spectroscopic distance of M giants with uncertainties of about 40%. A catalog of 8639 M giants is provided. As an additional result of this analysis, we also present a catalog of 101 690 M dwarfs/subdwarfs which are processed by our classification pipeline.

LAMOST Experiment for Galactic Understanding and Exploration (LEGUE)——The survey's science plan

We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope （GSJT, formerly calledthe Large sky Area Multi-Object fiber Spectroscopic Telescope -- LAMOST）. The survey will obtain spectra for 2.5 million stars brighter than r 〈 19 during dark/grey time, and 5 million stars brighter than r 〈 17 or J 〈 16 on nights that are moonlit or have low transparency. The survey will begin in the fall of 2012, and will run for at least four years. The telescope＇s design constrains the optimal declination range for observations to 10~ 〈 di 〈 50~, and site conditions lead to an emphasis on stars in the direction of the Galactic anticenter. The survey is divided into three parts with different target selection strategies： disk, anticenter, and spheroid. The resulting dataset will be used to study the merger history of the Milky Way, the substructure and evolution of the disks, the nature of the first generation of stars through identification of the lowest metallicity stars, and star formation through study of open clusters and OB associations. Detailed design of the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE） survey will be completed in summer 2012, after a review of the results of the pilot survey.

视超光速源3C345中射电节点的运动

在典型的视超光速源3C345中有两个射电节点C_4和C_5,沿着不同的弯曲轨道运动,并且在靠近核心处它们的运动出现加速.本文对这些观测到的运动特性提出一种解释.我们假定视超光速节点是沿着喷流内的螺旋形磁力线运动的.在简化的几何学考虑和小视角观测的情况下,用适当形式的螺旋磁场和空间速度,对节点C_4和C_5的视轨道和视运动速度可得到很好的拟合.

Evaluation of cable tension sensors of FAST reflector from the perspective of EMI

The active reflector of FAST （ five-hundred-meter aperture spherical radio telescope） is suppor- ted by a ring beam and a cable-net structure, in which nodes are actively controlled to form series of real-time paraboloids. To ensure the security and stability of the supporting structure, tension must be monitored for some typical cables. Considering the stringent requirements in accuracy and long- term stability, magnetic flux sensor, vibrating wire strain gauge and fiber bragg grating strain gauge are screened for the cable tension monitoring of the supporting cable-net. Specifically, receivers of radio telescopes have strict restriction on electro magnetic interference （EMI） or radio frequency in- terference （RFI）. These three types of sensors are evaluated from the view of EMIfRFI. Firstly, these fundamentals are theoretically analyzed. Secondly, typical sensor signals are collected in the time and analyzed in the frequency domain, which shows the characteristic in the frequency domain. Finally, typical sensors are tested in an anechoic chamber to get the EMI levels. Theoretical analysis shows that Fiber Bragg Grating strain gauge itself will not lead to EMI/RFI. According to GJB151 A, frequency domain analysis and test results show that for the vibrating wire strain gauge and magnetic flux sensor themselves, testable EMIfRF1 levels are typically below the background noise of the ane- choic chamber. FAST finally choses these three sensors as the monitoring sensors of its cable ten- sion. The proposed study is also a reference to the monitoring equipment selection of other radio tele- scopes and large structures.

Proof of Hubble’s Law and the Truth about the Expansion of the Universe as Well as Dark Matter and Dark Energy

In 1929,American astronomer Hubble first discovered that the recessional velocity of a galaxy increases with its distance from the earth,and therefore put forward Hubble’s law.It is considered the first observational basis for the expansion of the universe and today serves as one of the pieces of evidence most often cited in support of the Big Bang model.Since then the astrophysics community has believed that the universe is in a constant rate of expansion until Saul Permutter,Brian Paul Schmit and Adam Guy Riees discovered the accelerating expansion of the universe through observation of several dozen distant supernovas in 1998,who then won the Nobel Prize in Physics 2011.But human still cannot completely explain the phenomenon that the universe is expanding at an ever-accelerating rate.Thus the author of this paper studied the origin and evolution of galaxies again,and revealed the structure of galaxy and proved Hubble’s law,then revealed the truth about the expansion of the universe as well as dark matter and dark energy.

A New Consistency Test forΛCDM Cosmology Using Galaxy Surveys

We propose a new consistency test for theΛCDM cosmology using baryonic acoustic oscillations(BAO)and redshift space distortion(RSD)measurements from galaxy redshift surveys.Specifically,we determine the peak position of fσ8(z)in redshift z offered by an RSD measurement,and compare it to the one predicted by the BAO observables assuming a flatΛCDM cosmology.We demonstrate this new test using the simulated data for the DESI galaxy survey,and argue that this test complements those using the background observables alone,and is less subject to systematics in the RSD analysis,compared to traditional methods using values of fσ8(z)directly.

New tidal debris nearby the Sagittarius leading tail from the LAMOST DR2 M giant stars

We report two new sets of tidal debris nearby the Sagittarius （Sgr） tidal stream in the north Galactic cap （NGC） identified from the M giant stars in LAMOST DR2. The M giant stars located in the sky area of 210° 〈 A 〈 290°, and having a distance of 10-20 kpc and We/HI 〈 -0.75 show clear bimodality in their velocity distribution. We denote the two peaks as Vel-3＋83 for the one within a mean velocity of -3 km s^-1 with respect to that of the well observed Sgr leading tail at the same A and Ve1＋162＋26 for the other one with a mean velocity of 162km s^-1 with respect to the Sgr leading tail. Although the projected A-Vgsr relation of Vel-3＋83 is very similar to the Sgr leading tail, the opposite trend in the A-distance relation as compared to the Sgr leading tail suggests Vel-3＋83 has a different 3D direction of motion with any branch of the simulated Sgr tidal stream from Law ＆ Majewski. Therefore, we propose it is new tidal debris not related to the Sgr stream. Similarly, the other substructure Vel＋162＋26, which is the same one as the NGC group discovered by Chou et al., also moves toward a different direction with respect to the Sgr stream, implying that it may have a different origin than the Sgr tidal stream.

Wide-bandwidth drift-scan pulsar surveys of globular clusters:application to early science observations with FAST

The Five-hundred-meter Aperture Spherical Telescope （FAST） will begin its early-science oper- ations during 2016. Drift-scan pulsar surveys will be carried out during this period using an ultra-wide-band receiver system （covering - 270 to 1620 MHz）. We describe a method for accounting for the changes in the telescope beam shape and the pulsar parameters when searching for pulsars over such a wide bandwidth. We applied this method to simulated data sets of pulsars in globular clusters that are visible to FAST and found that a representative observation would have a sensitivity of -40 ply. Our results showed that a sin- gle drift-scan （lasting less than a minute） is likely to find at least one pulsar for observations of four globular clusters. Repeated observations will increase the likely number of detections. We found that pulsars in - 16 clusters are likely to be found if the data from 100 drift-scan observations of each cluster are incoherently combined.

An algorithm for preferential selection of spectroscopic targets in LEGUE

We describe a general target selection algorithm that is applicable to any survey in which the number of available candidates is much larger than the number of objects to be observed. This routine aims to achieve a balance between a smoothly- varying, well-understood selection function and the desire to preferentially select cer- tain types of targets. Some target-selection examples are shown that illustrate differentpossibilities of emphasis functions. Although it is generally applicable, the algorithm was developed specifically for the LAMOST Experiment for Galactic Understanding and Exploration （LEGUE） survey that will be carried out using the Chinese Guo Shou Jing Telescope. In particular, this algorithm was designed for the portion of LEGUE targeting the Galactic halo, in which we attempt to balance a variety of science goals that require stars at fainter magnitudes than can be completely sampled by LAMOST. This algorithm has been implemented for the halo portion of the LAMOST pilot sur- vey, which began in October 2011.

East Asian VLBI Network observations of active galactic nuclei jets:imaging with KaVA+Tianma+Nanshan

The East Asian Very Long Baseline Interferometry(VLBI) Network(EAVN) is a rapidly evolving international VLBI array that is currently promoted under joint efforts among China,Japan and Korea.EAVN aims at forming a joint VLBI Network by combining a large number of radio telescopes distributed over East Asian regions.After the combination of the Korean VLBI Network(KVN) and the VLBI Exploration of Radio Astrometry(VERA) into Ka VA,further expansion with the joint array in East Asia is actively promoted.Here we report the first imaging results(at 22 and 43 GHz) of bright radio sources obtained with Ka VA connected to Tianma 65-m and Nanshan 26-m Radio Telescopes in China.To test the EAVN imaging performance for different sources,we observed four active galactic nuclei(AGN) having different brightness and morphology.As a result,we confirmed that the Tianma 65-m Radio Telescope(TMRT) significantly enhances the overall array sensitivity,a factor of 4 improvement in baseline sensitivity and 2 in image dynamic range compared to the case of Ka VA only.The addition of the Nanshan 26-m Radio Telescope(NSRT) further doubled the east-west angular resolution.With the resulting high-dynamic-range,high-resolution images with EAVN(Ka VA+TMRT+NSRT),various fine-scale structures in our targets,such as the counter-jet in M87,a kink-like morphology of the 3 C 273 jet and the weak emission in other sources are successfully detected.This demonstrates the powerful capability of EAVN to study AGN jets and to achieve other science goals in general.Ongoing expansion of EAVN will further enhance the angular resolution,detection sensitivity and frequency coverage of the network.

Slowly rotating charges from Weyl double copy for Kerr black hole with Chern-Simons correction

The Weyl double copy builds the relation between gauge theory and gravity theory, in particular the correspondence between gauge solutions and gravity solutions. In this paper, we obtain the slowly rotating charge solutions from the Weyl double copy for the Kerr black hole with small Chern-Simons correction. Based on the Weyl double copy relation, for the Petrov type D solution in Chern-Simons modified gravity, we find the additional correction to the electromagnetic field strength tensor of the rotating charge. For the Petrov type I solution, we find that the additional electromagnetic field strength tensors have external sources, while the total sources vanish at the leading order.