Characteristics of the supernova remnant G351.7+0.8 and a distance argument against its association with PSR J1721−3532

New images of the supernova remnant (SNR) G351.7+0.8 are presented based on 21-cm H  i -line emission and continuum emission data from the Southern Galactic Plane Survey. SNR G351.7+0.8 has a flux density of 8.4 ± 0.7 Jy at 1420 MHz. Its spectral index is 0.52 ± 0.25 ( S = v ^−α) between 1420 and 843 MHz, typical of adiabatically expanding shell-like remnants. H  i observations show structures possibly associated with the SNR in the radial velocity range of −10 to −18 km s⁻¹, and suggest a distance of 13.2 kpc and a radius of 30.7 pc. The estimated Sedov age for G351.7+0.8 is less than  6.8×10⁴ yr  . A young radio pulsar PSR J1721−3532 lies close to SNR G351.7+0.8 on the sky. The new distance and age of G351.7+0.8 and recent proper motion measurements of the pulsar strongly argue against an association between SNR G351.7+0.8 and PSR J1721−3532. There is an unidentified, faint X-ray point source 1RXS J172055.3−353937 which is close to G351.7+0.8. This may be a neutron star potentially associated with G351.7+0.8.     

北方气温显著偏高云贵川渝降水偏多

2009年4月我国大部气温明显偏高,降水接近常年同期.月内南方局部发生洪涝;东北、华北喜降春雨;西北地区东北部等地气象干旱发展;     

Role of Sunspot and Sunspot-Group Rotation in Driving Sigmoidal Active Region Eruptions

We study active region NOAA 9684 (N06L285) which produced an X1.0/3B flare on November 4, 2001 associated with a fast CME (1810 km s⁻¹) and the largest proton event (31 700 pfu) in cycle 23. SOHO/MDI continuum image data show that a large leading sunspot rotated counter-clockwise around its umbral center for at least 4 days prior to the flare. Moreover, it is found from SOHO/MDI 96 m line-of-sight magnetograms that the systematic tilt angle of the bipolar active region, a proxy for writhe of magnetic fluxtubes, changed from a positive value to a negative one. This signifies a counter-clockwise rotation of the spot-group as a whole. Using vector magnetograms from Huairou Solar Observing Station (HSOS), we find that the twist of the active region magnetic fields is dominantly left handed (α_best = −0.03), and that the vertical current and current helicity are predominantly negative, and mostly distributed within the positive rotating sunspot. The active region exhibits a narrow inverse S-shaped H_α filament and soft X-ray sigmoid distributed along the magnetic neutral line. The portion of the filament which is most closely associated with the rotating sunspot disappeared on November 4, and the corresponding portion of the sigmoid was observed to erupt, producing the flare and initiating the fast CME and proton event. These results imply that the sunspot rotation is a primary driver of helicity production and injection into the corona. We suggest that the observed active region dynamics and subsequent filament and sigmoid eruption are driven by a kink instability which occurred due to a large amount of the helicity injection.     

疏散星团M11的研究：1.自行测定与成员研究

本文利用中国科学院上海天文台４０厘米双筒天体照相仪所拍摄得的１０对底片（历元差１６─７０年），经ＰＤＳ测量仪测量，共确定了疏散星团Ｍｌｌ天区８７２颗恒星的相对自行，其中８５％以上恒星的自行测定精度好于±０″．１／百年．利用所测得的相对自行和新的数学模型，确定了不同星等组恒星的分布参数并计算了团中心距ｒ≤２５＇内７８５颗恒星的成员概率，其中成员概率大于０．７的恒星共有５４１颗．详细的讨论表明，新方法不仅在理论上更为严格，实用上也是可行的，可以使星团成员确定取得更为合理的结果．     

SONG-China Project: A Global Automated Observation Networktwo

Driven by the technological advancements and scientific objectives, the data acquisition in observational astronomy has been changed greatly in recent years. Fully automated or even autonomous ground-based network of telescopes has now become a tendency for time-domain observational projects. The Stellar Observations Network Group (SONG) is an international collaboration with the participation and contribution of the Chinese astronomy community. The scientific goal of SONG is time-domain astrophysics, such as the astroseismology and the research of variable stars in open clusters. The SONG project aims to build a global network of one-meter telescopes equipped with high-precision and high-resolution spectrographs, and two-channel lucky-imaging cameras. It is the Chinese initiative to install a 50 cm binocular photometry telescope at each SONG node to share the network platform and infrastructure. This work is focused on the design and implementation of SONG/50BiN in technology and methodology, for the ground-based network composed of multiple sites and a variety of instruments.     

Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg

New multi-color BV RcIcphotometric observations are presented for the W UMa type eclipsing binary V1073 Cyg. The multi-color light curve analysis with the Wilson-Devinney procedure yielded the absolute parameters of this system, showing that V1073 Cyg is a shallow contact binary system with a fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119 yr,including CCD data to construct the O-C curve, and performed detailed O-C analysis. The O-C diagram shows that the period change is complex. A long-term continuous decrease and a cyclic variation exist. The period is decreasing at a rate of P =-1.04(±0.18) × 10~(-10) d cycle~(-1) and, with the period decrease, V1073 Cyg will evolve to the deep contact stage. The cyclic variation with a period of P_3= 82.7(±3.6) yr and an amplitude of A = 0.028(±0.002) d may be explained by magnetic activity of one or both components or the light travel time effect caused by a distant third companion with M_3(i′= 90?) = 0.511 M_⊙.     

Binary Star Fractions from the LAMOST DR4

Stellar systems composed of single, double, triple or higher-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through comparing the radial velocity variations from multiepoch observations, we analyze the binary fraction of dwarf stars observed with LAMOST. Effects of different model assumptions, such as orbital period distributions on the estimate of binary fractions,are investigated. The results based on log-normal distribution of orbital periods reproduce the previous complete analyses better than the power-law distribution. We find that the binary fraction increases with Teff and decreases with [Fe/H]. We first investigate the relation between α-elements and binary fraction in such a large sample as provided by LAMOST. The old stars with high [α/Fe] dominate with a higher binary fraction than young stars with low [α/Fe]. At the same mass, earlier forming stars possess a higher binary fraction than newly forming ones, which may be related with evolution of the Galaxy.     

LAMOST CCD camera-control system based on RTS2

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device(CCD) cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2 nd Version(RTS2) is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-frameworkbased control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.     

地震前水氡短临异常判别指标及预报三要素的方法探讨

本文分析了中国大陆(重点是南北地震带北段)水氧异常变化,深入研究了有震与无震异常的时空分布特征、异常总频次、起始异常时间差等,发现有震异常往往呈现“同步性”或“群体性”特征,而大部分“零散性”异常则属于非地震异常。根据上述研究,本文还提出了利用水氡异常预报地震的发震时间、地点和震级的初步方法。     

面向时空信息的智慧临沂建设实践

自智慧城市的概念提出以来,世界各国竞相开展智慧城市的研究和实践,国内各城市也迅速行动,纷纷开展智慧城市建设,以之作为转变发展方式、实现可持续发展的重要手段去推动。在智慧城市建设过程中,物联网、云计算、大数据、互联网+、移动互联等新技术取得了较大的发展进步和应用效果。该文在分析智慧城市概念和特征的基础上,介绍了测绘地理信息部门关于时空信息大数据和云平台建设的思路和关注点。梳理了智慧城市的总体框架,并对涉及的主要关键技术进行了分析。结合智慧临沂建设的实例,从基本情况、目标任务、主要内容、实现方式和实施进展等方面进行了详细介绍,并对智慧城市建设的重要作用进行了总结。智慧城市建设是一项复杂的系统工程,适合该地实际,能够切实解决该地实际问题的建设模式,才是智慧城市应该首要考虑的问题。