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Effects of mesoscale gravity waves on sporadic E simulated by a one-dimensional dynamic model

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Earth and Planetary Physics 2025年第1期9卷 1-9页

作者： Xu Zhou ZeZhong Li XinAn Yue LiBo Liu Key Laboratory of Earth and Planetary Physics/Heilongjiang Mohe National Geophysical observatory/Beijing National observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences(CAS)Beijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Mengcheng National Geophysical observatory University of Science and Technology of ChinaHefei 230026China

In addition to being driven by tidal winds,the sporadic E(Es)layers are modulated by gravity waves(GWs),although the effects are not yet comprehensively *** this article,we discuss the effects of mesoscale GWs on the Es layers determined by using a newly developed model,MISE-1D(one-dimensional Model of Ionospheric Sporadic E),with low numerical dissipation and high *** by the wind fields resolved by the high-resolution version of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension(WACCM-X),the MISE-1D simulation revealed that GWs significantly influence the evolution of the Es layer above 100 km but have a very limited effect at lower *** effects of GWs are diverse and complex,generally including the generation of fluctuating wavelike structures on the Es layer with frequencies similar to those of the *** mesoscale GWs can also cause increases in the density of Es layers,or they can disperse or diffuse the Es layers and increase their *** addition,the presence of GWs is a key factor in sustaining the Es layers in some cases.

关键词： sporadic E ion tidal layer gravity waves numerical simulation

Extended Corbet Diagram of HMXBs,LMXBs and radio pulsar binaries

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1726-1731页

作者： ALI Esamdin urumqi observatory National Astronomical ObservatoriesChinese Academy of Sciences

The evolutionary scenario of neutron star binaries is still an essential enigma in both stellar astrophysics and high energy *** order to explore the scenario,we include the accumulation of data on the orbits and spins of compact binaries in multi-wavelength ranging from radio to X-ray,such as radio pulsar binaries,HMXBs,and LMXBs,filling them into the so called "Corbet Diagram" which initially investigated the period of orbit(Porb)～the period of spin(Pspin) correlation of *** find that the evolutionary scenario comes more clearly and makes strong confirmation of the connection between LMXBs and radio pulsar binaries,predicted by the recycle ***,the origins of radio pulsar binaries sre still *** Induced Collapse(AIP) process may be a mechanism which can explain the origin of the binary millisecond pulsars with relatively longer orbital periods.A correlation of P1/3orb～P-1spin of LMXBs and radio pulsar binaries may exist.

关键词： neutron star X-ray binary pulsar

Understanding the Activity Performance of Comets 38P/Stephan-Oterma,64P/Swift-Gehrels and C/2017 M4(ATLAS)through Broadband Photometric Observations

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Research in Astronomy and Astrophysics 2024年第8期24卷 147-156页

作者： Xuan Zhang Jin-Zhong Liu Le-Tian Wang Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China

In this work,we report observations of three comets:38P/Stephan-Oterma,64P/Swift-Gehrels,and C/2017 M4(ATLAS),conducted with the Nanshan one-meter wide-field telescope in 2018 August and November,and *** extracted morphological features through image enhancement techniques and calculated the dust activity parameter,Afρ,along with dust mass loss rates and coma color indices using broadband photometric *** morphological analysis uncovered a spectrum of dust characteristics among the observed comets,ranging from a significant twisted structure in comet 38P/Stephan-Oterma’s coma to the regular coma envelope surrounding comet 64P/*** Afρvalues varied between 148.8±0.3 cm for 64P/Swift-Gehrels and1118.5±6.2 cm for C/2017 M4(ATLAS)(measured within a reference aperture radius ofρ=6″),indicating a range from moderate to high activity *** mass loss rates were estimated from 328.1 kg s^(-1)for comet 64P/Swift-Gehrels to 1395.5 kg s^(-1)for comet C/2017 M4(ATLAS).The color indices of comets 38P/Stephan-Oterma and C/2017 M4(ATLAS)closely resemble the average colors of active short-period comets and active longperiod comets,*** contrast,64P/Swift-Gehrels exhibits a significantly bluer hue than typical Jupiter family comets.

关键词： comets general-comets individual(38P/Stephan-Oterma,64P/Swift-Gehrels,C/2017 M4(ATLAS))-techniques photometric

Infrared Characteristics of Associated Sources of Water Masers

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Chinese Journal of Astronomy and Astrophysics 2005年第6期5卷 587-594页

作者： Jarken Esimbek Yue-Fang Wu Jun-Zhi Wang Department of Astronomy Peking University Beijing 100871 National Astronomical Observatories/urumqi observatory Chinese Academy of SciencesUrumqi 830011

We present an analysis of the infrared properties of 1417 water masers collected from the literature published by December 2004. The associated infrared sources of the water masers were identified with IRAS and MSX （Midcourse Space Experiment） catalogues. There are 1252 water masers associated with IRAS sources within 11, which include 700 interstellar and 552 stellar sources. For 382 sources, the IRAS counterpart identification and the maser classification are new. We found the colors of the interstellar maser sources are much redder than those of the stellar ones at IRAS wavelength bands; 99% of the interstellar maser sources are above black body line, while 95% of the stellar masers are below. The distribution difference of the two kinds of masers shown in the color-color diagram is due to their different optical depths and temperature distributions of dust regions. There are 743 water masers with MSX counterparts, of which 552 are interstellar masers and 191 are stellar masers. MSX colors of the associated sources of water masers are here analyzed for the first time. The color differences among the MSX bands are small and the interstellar masers are redder than the stellar masers. There is a correlation between the intensity of the stellar water maser emission and that of the 12μm and 25μm emissions, while there is no correlation between the water maser emission and the 8μm emission. The infrared intensity increases with increasing wavelength for the interstellar masers, while it is the opposite for stellar masers. These results may provide clues for the pumping of water maser and for the properties of the two kinds of maser emission regions.

关键词： masers - ISM kinematics and dynamics - stars mass loss

Design of the cryogenic system of the wideband phased array feed for QTT

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Research in Astronomy and Astrophysics 2021年第4期21卷 168-172页

作者： Jun Ma Yang Wu Song Xiao Sheng-Pu Niu Kai Wang Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China

Phased array feeds(PAFs),which illuminate the dish with digitally synthesized beams instead of separated horns,provide the capability for wider and continuous field-of-view *** a promising technology for next generation radio telescopes,PAFs will provide the Qi Tai Telescope(QTT),which will be next world-class fully steerable radio telescope,an opportunity of reaching several cutting-edge science *** paper presents a brief introduction of the wideband PAF for QTT,and the detailed design and simulation of the cryogenic *** on this design,a scaled prototype of the spherical vacuum window,which is the key part of the cryogenic system,has been built and the performance is verified.

关键词： Phased Array Feed Vacuum window Cryo telescope

A Possible Origin of 6.7 GHz Linear Methanol Maser Sources

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Chinese Journal of Astronomy and Astrophysics 2001年第5期1卷 389-394页

作者： Ye Xu (Shanghai Astronomical observatory, Chinese Academy of Sciences, Shanghai 200030) (urumqi Astronomical observatory, Chinese Academy of Sciences, urumqi 830011) (National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012) E-mail Shanghai Astronomical observatory Chinese Academy of Sciences Shanghai 200030 []Urumqi Astronomical Observatory Chinese Academy of Sciences Urumqi 830011 []National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

We present a model which explains the observed multi-linear spatial structures with different velocity gradients of the 50-61A+ methanol line at 6.7 GHz. We consider this and other hypotheses and conclude that the met... 详细信息

关键词： masers - stars: circumstellar matter - stars: formation

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

Observations of Giant Pulses of the Crab Pulsar

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Chinese Journal of Astronomy and Astrophysics 2008年第3期8卷 277-284页

作者： Ling-Jun Kong Ali Esamdin Cheng-Shi Zhao Zhi-Yong Liu Jian-Ping Yuan urumqi observatory NAOC Chinese Academy of Sciences Urumqi 830011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The Crab Pulsar was observed at 1540MHz with the 25m radio telescope at urumqi with a filterbank de-dispersion backend. A total of 2436 giant pulses with pulse energies larger than 4300 Jy μs were detected in two observing sets. All of these giant pulses are located in the main pulse （MP） and inter pulse （IP） windows of the average profile of the Crab Pulsar. The ratio of the numbers of giant pulses detected in the IP and MP windows is about 0.05. Our results show that, at 1540MHz, the emission in the IP is contributed by giant and normal pulses, while that in the MP is almost dominated by giant pulses. The distribution of energy of the 2436 giant pulses at 1540 MHz can be described by a power-law with index α = 3.13 ± 0.09. The intrinsic threshold of giant pulse energy in the MP window is about 1400Jy μs at 1540MHz.

关键词： stars neutron -- pulsars general -- pulsars individual Crab Pulsar

A method to obtain the wind field characteristics of super-large aperture radio telescope site based on single-point wind tower and numerical simulation

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Research in Astronomy and Astrophysics 2020年第12期20卷 270-278页

作者： Fei-Long He Qian Xu Na Wang Chun-Hua Zhu School of Physics and Technology Xinjiang UniversityUrumqi 830046China Xinjiang Astronomical observatory Chinese Academy of SciencesUrumqi 830011China

The influence of wind on the pointing accuracy of large aperture radio telescopes is becoming increasingly serious, especially at high observing frequency. Obtaining the wind field characteristics efficiently is very important to reduce the wind disturbance on antenna structure. In this paper, an error evaluation of numerical simulation method is established based on the measured data of single point wind tower, and the wind field characteristics are obtained from the evaluated numerical simulation results combined with the measured data for the 110 m aperture Qi Tai radio Telescope(QTT) site. According to the simulation results, compared with the measured data, the root mean square error(RMSE) of wind speed is less than 1 m s^-1, and the minimum wind speed RMSE is 0.2 m s^-1. An analysis of the wind field characteristics of the QTT site suggests that the active wind resistance design of the antenna periphery should focus on the SSW(south-south-west) direction.

关键词： telescopes site testing methods:data analysis