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Measuring the Distance of VX Sagittarii with SiO Maser Proper Motions

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Chinese Journal of Astronomy and Astrophysics 2007年第4期7卷 531-538页

作者： Xi Chen zhi-qiang shen Ye Xu Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 Department of Earth Sciences National Taiwan Normal University 88 Sec. 4 Ting-Chou Rd. Taipei 116 Taiwan

We report on 43 GHz v=1, J=1-0 SiO maser proper motions in the circumstellar envelope of the M-type semi-regular variable star VX Sgr, observed by Very Long Baseline Array （VLBA） at 3 epochs during 1999 April-May. Applying the statistical parallax analysis to these proper motions, we estimated a distance of VX Sgr of 1.57±0.27kpc, which is consistent with that based on the proper motions of H20 masers, or on the assumption that VX Sgr belongs to the Sgr OB1 association. At this distance, VX Sgr can be classified as a red supergiant. Comparing the statistical parallax method with those of model fitting and annual parallax, we think that the statistical parallax method may be a good way of estimating SiO maser distances at present.

关键词： methods: statistical - masers -stars: individual (VX Sgr)- stars: distances

A Composite Model for GHz Peaked Spectra of Radio Sources

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Chinese Journal of Astronomy and Astrophysics 2005年第6期5卷 563-570页

作者： Jun Yang Xiang Liu zhi-qiang shen National Astronomical Observatories/Urumqi Observatory Chinese Academy of Sciences Urumqi 830011 Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 Graduate University of the Chinese Academy of Sciences Beijing 100049

GHz-Peaked Spectrum （GPS） radio sources are powerful and compact sources with convex spectra. With increasing observational findings, it has been realized that either Synchrotron Self-Absorption （SSA） alone or Free-Free Absorption （FFA） alone is not enough to account for all the spectral features. We present a model consisting of an SSA region partially covered by FFA plasma, and derive a composite spectral formula. By applying the model to a sample of 19 GPS sources having strong absorption, it is found that the external FFA process makes the SSA peak frequency linearly shift to a higher （observed） peak frequency. The shift indicates that the FFA does play a role at the frequency close to the observed peak frequency.

关键词： radio continuum: galaxies -- galaxies: active -- quasars: general

Preface: Key technologies for enhancing the performance of FAST

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Research in Astronomy and Astrophysics 2020年第5期20卷 63-64页

作者： Peng Jiang zhi-qiang shen Ren-Xin Xu CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Department of Radio Science and Technology Shanghai Astronomical ObservatoryShanghai 200030China School of Physics and Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The Five-hundred-meter Aperture Spherical radio Telescope(FAST)passed its national acceptance inspection on 2020 January *** special issue includes a total of 15 papers,which are selected to introduce the status of FAST’s performance and demonstrate the key technologies applied to *** presented performance parameters can provide an important reference for scientists to propose observations with *** key technologies presented in these papers include design and implementation in the measurement and control system,electromagnetic compatibility system,and receiver ***,scientific achievements obtained by FAST during the commissioning phase are also reported.

关键词： telescope techniques:radar astronomy methods:data analysis methods:observational techniques:interferometric

Seven-frequency VLBI Observations of the GHz-Peaked-Spectrum Source OQ 208

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Chinese Journal of Astronomy and Astrophysics 2007年第5期7卷 611-619页

作者： Wen-Feng Luo Jun Yang Lang Cui Xiang Liu zhi-qiang shen National Astronomical Observatories / Urumqi Observatory Chinese Academy of Sciences Urumqi 830011 Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 Graduate School of Chinese Academy of Sciences Beijing 100049 Joint Institute for Galaxy and Cosmology SHAO and USTC

We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4, 1.7, 2.3, 5.0, 8.4, 15.4 GHz and the European VLBI Network at 6.7 GHz. The low frequency （1.4, 1.7 and 2.3 GHz） observations reveal a weak and extended steep-spectrum component at about 30 mas away at position angle - 110°, which may be a remnant emission. The radio structure of OQ 208 consists of two mini-lobes at 5.0, 6.7, 8.4 and 15.4 GHz. Our spectral analysis further confirms that the southwest lobe undergoes free-free absorption and finds that the free-free absorption is stronger in the inner region. By fitting the 8.4 GHz images from 1994 to 2005, we obtain a separation speed of 0.0314-0.006 mas yr^-1 between the two mini-lobes. This indicates a jet proper motion of 0.1054-0.020 c and a kinematic age of 219±42 yr for the radio source.

关键词： galaxies individual (OQ 208) -- radio continuum galaxies

Observational characteristics of SiO masers around VX Sgr

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Research in Astronomy and Astrophysics 2020年第12期20卷 196-204页

作者： Jiang-Bo Su zhi-qiang shen Xi Chen Jing Liu Yan Wang Yi-Bin Zhao Department of Physics and Electronics Yuncheng UniversityYuncheng 044000China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China

SiO maser VLBA observations toward VX Sgr are performed at five epochs, and lots of maser spots are obtained. We make a statistical analysis on these spots. It is shown that the apparent sizes and the fluxes of maser spots decrease with increasing the distance from the central star. In addition, the similarity between the v = 1,2(J =1–0) spectrums increases with epochs, consistent with the full width at half maximum(FWHM), while the total fluxes increase. The results may be related to the changeable pumping mechanisms.

关键词： masers stars:individual(VX Sgr) techniques:interferometric turbulence

Roles of Nano-Domain Switching and Non-180° Domains in Enhancing Local Piezoelectric Responses of Highly （100）-Oriented Pb(Zr0.60Ti0.40)O3 Thin Films

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Chinese Physics Letters 2019年第10期36卷 86-89页

作者： Chen-Fei Jin Si-Qi Zhang zhi-qiang shen Wei-Li Li School of Physics Harbin Institute of TechnologyHarbin 150001 School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001

Ferroelectric Pb(Zr0.60Ti0.40)O3 thin films deposited on the niobium-doped SrTiO3 and Pt(111)/Ti/SiO2/Si substrates are fabricated by a sol-gel method.X-ray diffraction indicates that the films have a ’cube-on-cube’growth with highly(100)preferred orientation and good surface *** piezoelectric force microscopy,we investigate domain structures and butterfly amplitude loops of ferroelectric thin *** results indicate that the film deposited on Nb:SrTiO3 has both kinds of 180° polarizations perpendicular or parallel to the surface while the film deposited on Pt/Ti/SiO2/Si has irregular phase *** piezoelectric polarization are observed in the films on niobium-doped SrTiO3 with local d33* values around 45 pm/V three times more than that of the films around 13 pm/V deposited on Pt(111)/Ti/SiO2/Si. Our findings emphasize that nanodomain switching ability and non-180° domains will contribute significantly to enhance piezoelectric responses of ferroelectric thin films.

关键词： method. piezoelectric ferroelectric

One large glitch in PSR B1737-30 detected with the TMRT

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Research in Astronomy and Astrophysics 2019年第5期19卷 113-122页

作者： Jie Liu Zhen Yan Jian-Ping Yuan Ru-Shuang Zhao zhi-Peng Huang Xin-Ji Wu Na Wang zhi-qiang shen Shanghai Astronomical Observatory Chinese Academy of Sciences School of Physical Science and Technology ShanghaiTech University University of Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences Xinjiang Astronomical Observatory Chinese Academy of Sciences School of Physics Peking University

One large glitch was detected in PSR B1737-30 using data spanning from MJD 57999 to 58406 obtained with the newly built Shanghai Tian Ma Radio Telescope(TMRT). The glitch took place at the time around MJD 58232.4 when the pulsar underwent an increase in the rotation frequency of △v about 1.38 × 10^(-6) Hz, corresponding to a fractional step change of △v/v～ 8.39 × 10^(-7). Post-glitch v gradually decreased to the pre-glitch value. The frequency derivative was observed to undergo a step change of about-9×10^(-16) s^(-2). Since July 1987, there have been 36 glitches already reported in PSR B1737-30 including this one. According to our analysis, the glitch size distribution is well described by a power law with an index of 1.13. The distribution of the interval between two adjacent glitches(waiting time △T) follows a Poisson probability density function. For PSR B1737-30, the interval is prone to be long after a large glitch. However, no correlation is found between glitch size and the interval since the previous glitch.

关键词： stars:neutron pulsars:general pulsars:individual:B1737-30

Effects of environment and genotype-by-environment interaction on phenotype of Rorippa elata(Brassicaceae),an endemic alpine plant in the Hengduan mountains

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Journal of Plant Ecology 2024年第4期17卷 42-55页

作者： zhi-qiang Du Yao-Wu Xing Ting-shen Han CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla 666303China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Plant Diversity and Specialty Crops Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla 666303China

Global climate change poses a severe threat to mountain *** plasticity and local adaptation are two common strategies for alpine plant to cope with such *** may facilitate organismal adaptation to contrasting environments,depending on the influences of the environment or genotype or their interacted *** this study,we use an endemic alpine plant(Rorippa elata)in the Hengduan mountains(HDM)to unravel its phenotypic basis of adaptation strategy and evaluate the relative contributions of environment and genotype to its *** transplanted 37 genotypes of *** into two common gardens across low and high elevations(2800 vs.3800 m)during *** fitness-related traits were measured,including flowering probability and glucosinolates(GS)*** estimated the environmental or genotypic contributions to the phenotype and identified the main environmental *** results revealed that both environment and genotype-by-environment interactions contributed to the phenotypes of *** heterogeneity was identified as a key factor that explained 24%of the total phenotypic *** particular,genotypes of the northern HDM showed significantly higher plasticity in flowering probability than those of the southern ***,within the southern HDM,GS content indicated local adaptation to herbivory stresses for *** genotypes along *** conclusion,our results suggest that *** may have adapted to the alpine environment through species-level plasticity or regional-level local *** processes were shaped by either complex topography or interactions between genotype and mountain *** study provides empirical evidence on the adaptation of alpine plants.

关键词： alpine plant common garden genotype-by-environment Hengduan mountains local adaptation phenotypic plasticity

A 95 GHz methanol emission survey toward eight small supernova remnants

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Research in Astronomy and Astrophysics 2017年第12期17卷 65-76页

作者： Ying-Jie Li Ye Xu Xi Chen Deng-Rong Lu Yan Sun Xin-Yu Du zhi-qiang shen Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008China University of Science and Technology of China Chinese Academy of SciencesHefei 230026China Center for Astrophysics Guangzhou UniversityGuangzhou 51006China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of the Chinese Academy of Sciences Beijing 100049China

We report on a 95 GHz（80-71A＋） methanol（CH3OH） emission survey with the Purple Mountain Observatory Delingha 13.7 m telescope. Eight supernova remnants（SNRs） with angular size〈10′ were observed, but emission was only detected in three SNRs near the Galactic center（Sgr A East,G 0.1–0.1 and G 359.92–0.09）. CH3OH emission mainly surrounds the SNRs and can be decomposed into nine spatial peaks with the velocity range of eight peaks being（-30, 70） km s-1, and the other is（70, 120） km s-1. They are probably excited by interaction with these SNRs and adjacent molecular gas in the central molecular zone（CMZ）, although star formation may play an important role in exciting CH3OH emission in some regions of CMZ. We infer that tidal action is unlikely to be an excitation source for CH3OH emission.

关键词： ISM:molecules ISM:supernova remnants Galaxy:center ISM:kinematics and dynamics ISM:clouds