Subjects: Astronomy >> Astrophysical processes submitted time 2016-11-16
Abstract:本文提出了一种天象厅环境下的座席区设计方法,该方法将天象厅中的观众体验感分为五类,将感官体验量化,分别进行数学建模,然后将五个模型根据比重综合,得到天象厅中体验感的数学模型,对其进行分析得出较优的座席区范围,并引入偏转角变量设计了固定座席区与旋转座席区。并针对天象厅超大垂直面视野设计了一种座椅,该座椅能舒适地为观众提供较大的仰角观看节目
Peer Review Status:Awaiting Review
Subjects: Physics >> Geophysics, Astronomy, and Astrophysics Subjects: Physics >> Atomic and Molecular Physics submitted time 2016-12-10
Abstract:通常的狭义相对论是在庞加莱变换下不变的,它的基本度规为闵科夫斯基时空度规,该度规满足没有宇宙学常数Λ的真空爱因斯坦方程。本文指出:Λ≠0 时的狭义相对论是德西特/反德西特不变狭义相对论。求解Λ≠0的真空爱因斯坦方程,得到这种拓展的狭义相对论的基本度规是陆启铿-邹振隆-郭汉英1974年提出的Beltrami 度规;用欧拉-拉格朗日方程证明Beltrami时空的自由粒子运动是惯性运动。本文求出了德西特/反德西特不变狭义相对论的全部凯林(Killing) 矢量,证明了Beltrami 时空是最大对称性空间。导出来全部守恒量。构造了理论的正则形式,发现了正、负正则能量的色散关系的不对称性;实现了正则量子化,导出了相对论性波方程,从而建立了德西特/反德西特不变的相对论量子力学。简要介绍了通过天文观测原子(或离子)能级劈裂来探测精细结构常数#11;改变的实验。实验结果在4 ∼ 5σ 置信度内否定了庞加莱不变狭义相对论的预言,发现在z ≈ {1 ∼ 3}处αz ̸= α0。由于原子或离子能级的精细结构是相对论量子力学的结果,所以观测实验支持在红移z ≥ 1的狭义相对论量子力学中的Λ修正不可忽略。这是对德西特/反德西特不变狭义相对论的实验支持。是超出现有物理学标准模型的新物理。
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2019-11-27 Cooperative journals: 《天文研究与技术》
Abstract: 水切伦科夫探测器阵列(WCDA)是高海拔宇宙线观测站(LHAASO)的主体探测之一,水作为探测器的唯一探测介质,水的洁净度将直接影响探测器对切伦科夫光的探测效率。为保证WCDA物理目标的实现,水衰减长度的实时测量和监测至关重要,是探测器正常运行和标定的关键工作之一。本实验分别介绍了水衰减长度测量装置和紫外可见分光光度计的工作原理,并通过不同波长的LED对各种样品水进行测量,将两种方法的数据结果进行对比分析,找出了两种装置的测量误差分别为0.22m和0.18m,以及工业指标吸光度与科研指标水衰减长度之间的对应关系,并为GEANT4模拟确定了一种Querry水质模型,进一步推进了模拟的真实化。通过对WCDA一号水池水衰减测量装置的验证及从注水到稳定运行期间的水质监测的数据研究,总结了一套稳定可靠的水质监测方案,为二、三号水池的监测工作奠定了良好的基础。
Subjects: Astronomy >> Astrophysical processes submitted time 2017-09-26 Cooperative journals: 《天文研究与技术》
Abstract:海量观测数据及次生数据的高效存储与检索,天文大数据的快速及时处理,加速天文学研究的科学产出等问题,已成为天文观测和天文研究迫切需要解决的难题。以信息技术为支撑的天文大数据的高效分析和处理,帮助天文学家重新审视和了解宇宙。虚拟天文台的出现为全球范围内研究资源的无缝透明连接提供了协议、标准,以协议为基拙规范了天文数据的发布与检索方式。以国内外现有的观测设备为基拙,综述目前主流天文机构的数据发布与检索相关情况。
Subjects: Astronomy >> Star and Galactic System submitted time 2017-08-17
Abstract:Aims. The quiescent periodic photometric modulations of two low-inclination cataclysmic variables observed in Kepler K2 Campaigns 0 and 1, KZ Gem and TW Vir, are investigated. Methods. A phase-correcting method was successfully used to detect the orbital modulations of KZ Gem and TW Vir and improve their orbital periods. The light curve morphologies of both CVs were further analyzed by defining flux ratios and creating colormaps. Results. KZ Gem shows ellipsoidal modulations with an orbital period of 0.22242(1) day, twice the period listed in the updated RK catalogue (Edition 7.24). With this newly determined period, KZ Gem is no longer a CV in the period gap, but a long-period CV. A part of the quiescent light curve of TW Vir that had the highest stability was used to deduce its improved orbital period of 0.182682(3) day. The flat patterns shown in the colormaps of the flux ratios for KZ Gem demonstrate the stability of their orbital modulations, while TW Vir show variable orbital modulations during the K2 datasets. In TW Vir, the single versus double-peaked nature of the quiescent orbital variations before and after superoutburst may be related to the effect of the superoutburst on the accretion disk.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrometry Subjects: Library Science,Information Science >> Information Science Subjects: Physics >> Atomic and Molecular Physics submitted time 2021-03-05
Abstract: " Gravitational wave signals were directly detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015, bring hope to new physics and astrophysics and setting off a new wave of the development of laser interferometer gravitational wave detectors. In the background of the vigorous development of the interferometer gravitational wave detectors from ground to space, a comparative study of each detector are carried out from the aspects of construction history, technical characteristics and development positioning, and operation mode. And the experiences and enlightenments of the construction and operation of laser interferometer gravitational wave detectors are further summarized, namely: the construction of laser interferometer gravitational wave detector is a long-term project, which helps to promote the perfect development of scientific research fault tolerance mechanism and scientific evaluation mechanism; the construction of gravitational wave detector is a high-tech project, which helps to promote the coordinated development of multidisciplinary technologies; the construction of laser interferometer gravitational wave detectors is an international project, which helps to promote the healthy development of scientific research cooperation.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysics Subjects: Astronomy >> Star and Galactic System submitted time 2018-09-12
Abstract: We used the light curve code XRBinary to model the quiescent K2 light curves of three low-inclination cataclysmic variables (CVs): 1RXS\,J0632+2536 (J0632+2536), RZ\,Leo, TW\,Vir and the pre-CV WD\,1144+011. Optimized light curve models were obtained using a nonlinear fitting code NMfit and visualized by Phoebe 2.0. The disk model of J0632+2536 shows that one hotspot at the edge of the disk is enough to describe its light curve, while the other two dwarf nova (DN): RZ\,Leo and TW\,Vir require two hotspots. A typical pre-CV model with a weak irradiation effect for WD\,1144+011 can explain its single-hump modulation and the newly observed spectrum confirms its previous classification. The synthetic analyses for the DN clearly indicate that phase zero of the double-hump modulations occurs around the secondary minimum and the primary hump is mainly caused by the hotspot at the edge of the disk. The quiescent disk has a flat temperature distribution with a power index of $\sim0.11$. The disk model of RZ\,Leo implies a truncated disk, supporting its previously speculated classification as an intermediate polar (IP). Except for the IP model of RZ\,Leo, which lacks a component related to the inferred accretion curtain, the models of J0632+2536, TW\,Vir and WD\,1144+011 are consistent with results from the Gaia mission. The derived masses and radii of the secondaries of the three DN are consistent with the semi-empirical relations for CV donor stars, while their effective temperatures are higher than the predictions. Irradiation of the donor stars is investigated to explain this discrepancy."
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysics submitted time 2018-02-07
Abstract: In the present letter, with the help of a semi-analytical code we show how taking into account baryonic physics in the #3;CDM model can solve the discrepancy between the numerical predictions of dark matter haloes in the #3;CDM framework and observations from dwarf galaxy scale to clusters of galaxies without the need of different forms of dark matter as recently advocated by [1]. Combining well established results, the paper shows, for the first time, how the flat profiles of galaxy clusters and correlations between several of their main properties, are naturally obtained when baryon physics is correctly taken into account; how the so called ”diversity problem” can be solved and how the challenging, extremely low rising rotation curve of IC2574 can very well be reproduced when baryon physics is taken into account. We therefore suggest that before introducing new exotic features in the standard cosmological model, albeit legitimate, baryonic physics should be treated properly to reach agreement with observations.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2018-05-15 Cooperative journals: 《天文研究与技术》
Abstract:新疆天文台Taurus高性能计算系统由1个登陆节点、16个计算节点、2个I/O节点、100TB高速存储组成。其CPU理论双精浮点计算能力6.7584Tflops,通过Linpack测试实际峰值为6.289Tflops,可提供计算能力为理论值的93.06%;GPU理论计算能力18.72 Tflops,实际测试计算峰值为14.882Tflops,计算效率为理论能力的79.5%。系统计算与存储节点均采用56Gb Infiniband交换互连,通过IOZone测试存储系统,单节点写可达460MB/s,多节点写可达800MB/s。系统已在多相滤波及消干扰GPU算法加速、蒙特卡罗模拟等领域得到了应用。
Subjects: Astronomy >> Astrophysical processes submitted time 2017-10-20 Cooperative journals: 《天文研究与技术》
Abstract:中国明安图超宽频谱射电日像仪(Mingantu Ultrawide Spectral Radioheliograph ,MUSER)进入实际观测后,每3 ms产生一帧100 kB左右的数据,每天的原始观测数据约3. 5 TB。由于射电日像仪的原始数据采用自定义格式,为了后续数据分析和共享的需要,有必要根据数据存储需求把这些原始数据转换成天文常用的文件格式。在前期工作中已经实现了原始数据格式到UVFITS文件的转换,在此基拙上研究了基于MPI的集群并行环境下UVFITS合成系统性能优化。通过实验验证,在改进后的并行环境下,UVFITS合成系统的性能达到了需求的2. 5倍,可以有效处理当前及未来一定时间内射电日像仪的海量观测数据。同时,改进后的系统具有良好的横向扩展能力,能够为相关项目的数据处理提供借鉴和参考。
Subjects: Astronomy >> Astrophysics submitted time 2018-09-16
Abstract: This paper introduces the inverse dissipation potential into the Newtonian Dynamic equation and studies the motion equations of the objects in the isolated gravitational system. It is found that at large scales it can derive the dynamical equation of cosmic expansion similar to the ΛCDM model and yield the flat rotation curves for spiral galaxy. Different from the usual dark matter models, the derived flat rotation curves are the result of time accumulation rather than the direct action of mechanics. And the Tully-Fisher relationship is also discussed, it is found that the basic constant a0 in the MOND model and the form of the function μ have a clear corresponding physical significance in the model of this paper.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysics submitted time 2017-05-12
Abstract:摘要:与类木行星等气态巨行星相比,冰巨星是由大量比氢氦重的气体成分(水、氨、摘要:与类木行星等气态巨行星相比,冰巨星是由大量比氢氦重的气体成分(水、氨、甲烷等)组成的气体行星,天天星和海王星便是典型的冰巨星。天王星和海王星的大气中保存着太阳系形成初期的气体,对研究太阳系和行星的形成演化有很大帮助;对其大气的动力学研究可以了解到大气内部的结构、热源驱动机制和对流机制;随着证认的系外行星数量逐渐增加,发现类海王星型系外行星是普遍存在的。梳理了天王星和海王星的大气结构和大气成分以及太阳系外类海王星的研究进展,并对未来冰巨星的探测和研究做了展望。 关 键 词:行星;冰巨星;大气;成分;系外行星 1 引 言 冰巨星是指内部结构中有大量“冰”存在的巨行星,这种“冰”是由原始行星盘中低折射率的物质(比如H2O, CH4, NH3等)冷凝而成[1],其外围仍存在有大量的氢和氦。天王星和海王星是典型的冰巨星。天王星和海王星的成分和内部结构反映出了不同于气态巨行星(木星和土星)的形成环境和演化过程[2],同时二者在表面温度,有效温度,磁场结构、大气纬向环流等物理特征方面都十分的类似 [3]。天王星和海王星的质量分别为14.5M?和17.1M?(M?为地球质量),由于冰巨星的引力势能较大,对于太阳系的形成起到了重要的作用,它们保留了大量太阳系形成初期的气体[1],包含着原恒星云的状态条件和行星形成的位置信息[2],因此研究冰巨星的大气成分和大气结构不仅有助于研究其内部热源的驱动机制和对流机制,也有助于研究太阳系和行星的形成及演化历史。 在太阳系内的冰巨星(天王星、海王星)由于距离比较远,目前只有 1977 年美国发射的“旅行者 2 号”飞行器对其进行过飞掠探测[4-6],此后便没有飞行器对其进行过近距离考察。根据“旅行者 2 号”飞行器的射电掩星观测[7, 8],木星和土星的大气温度分别为165 ± 5K和134 ± 4K(1bar处),而天王星和海王星的大气温度分别为76 ± 2K和72 ± 2K(1bar处),可见冰巨星的大气温度是远远低于气态巨行星的。 气态巨行星有大体积的气态
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Galaxy and Cosmology submitted time 2018-03-27
Abstract: We study how deviations from spherical symmetry of a system, produced by angular momentum, and shear stress, modify the spherical collapse model, as linear density threshold for collapse of the non-relativistic com-ponent (δ c ) and its virial overdensity (∆ V ), in Einstein-de Sitter and ΛCDM models. We modify the sphericalcollapse model to take account of the shear term and angular momentum term. We find that the non-sphericalterms change the non-linear evolution of the system and that the collapse stops “naturally” at the virial ra-dius. Moreover, values of the linear overdensity parameter and of ∆ V are modified with respect to the standard spherical collapse model.
Peer Review Status:Awaiting Review
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. Subjects: Physics >> Geophysics, Astronomy, and Astrophysics submitted time 2019-03-31
Abstract: Ideas and theories of turbulence based on modifying the Navier-Stokes equation, to obtain equilibrium and non-equilibrium time-reversible dynamical ensembles relevant to helical turbulence, are presented. Discussions of controlling helicity to control the aerodynamic force, heat and noise are presented, together with the compressible turbulence relevant statistical mechanics analysis. A helical time-reversible system for nonequilibrium dynamical ensemble is constructed. Applications are also remarked.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astronomical Instruments and Techniques submitted time 2018-06-22 Cooperative journals: 《天文研究与技术》
Abstract: SAGE photometric system is a self-designed system, which can provide accurate stellar atmosphere parameters and extinction. The actual 100σ depths of the single-epoch images are uSC ~ 17.3 and vSAGE ~ 16.8 (AB magnitude). We are performing a SAGE photometric sky survey of the northern sky, covering about 12,000 squared degrees and over 500 million stars. This will be valuable data in research of the Milky Way. This paper introduces the research and development of the pipeline for the survey, particularly the data reduction process of a single exposure. The procedures include bias and flat correction, astrometric calibration, photometry and flux calibration. This paper also introduces the main results and data quality produced by the pipeline.
Subjects: Astronomy submitted time 2018-12-04 Cooperative journals: 《天文研究与技术》
Abstract:射电干涉阵列宽视场成像网格化处理过程中必须考虑w项的影响。w-projection和w-stacking是两个重要的宽视场成像网格化处理算法, w-plane参数是算法中影响计算速度和成图质量的一个重要因素。本文研究了w-projection和w-stacking两种网格化算法,利用SKA1低频阵台站数据和ASKAP软件包进行模拟观测,对两种算法在不同w-plane参数取值情况下的成图速度和成图质量进行了定量分析对比。结果进一步表明w-plane是性能改善的重要参数,针对w-projection算法来说,w-plane取值应比一般给定的经验值要大才能较好的得到成像效果。w-stacking算法虽然有很大的速度优势,但算法实现中w-plane的影响更为显著,论文给出了推荐的w-plane取值。本文工作是大视场成像算法的基础研究工作,对未来SKA科学数据处理中的管线设计有较好的参考价值。
Subjects: Astronomy >> Astrophysical processes submitted time 2017-09-26 Cooperative journals: 《天文研究与技术》
Abstract:中国古代对星空命名中的星宿、星官和星座是有区别的。星宿指二十八宿,它们作为计量天体的坐标,不考虑作为恒星或星座存在的意义。星官是指该星座作为官员星名而言,若星名没有官员的含义,则不可称星官而称星座。因此星座使用的范围更广,天官星名、动物星名和其它星名也可以叫星座。二十八宿也可叫二十八星座。以往的误解需要澄清。
Subjects: Astronomy >> Astrophysics submitted time 2020-03-09
Abstract: We present spectroscopy of stars in the immediate vicinity of the dwarf nova (DN) KZ Gem to confirm its identification, which had been ambiguous in the literature. Analysis of 73 radial velocities spanning from 2014 to 2019 provides a high-precision orbital period of 0.2224628(2) d (~5.34 hr) and shows KZ Gem to be a double-lined DN. Time series photometry taken from 2016 to 2018 shows a variable double-hump modulation with a full amplitude of ~0.3 mag, along with five Gaussian-like transient events lasting ~30 min or more. Using the light curve code XRBinary and nonlinear fitting code NMfit, we obtain an optimized binary model of the dwarf nova (DN) KZ Gem, from time series photometry, consisting of a Roche-lobe-filling K type dwarf with a mass transfer rate of 2.7 - 7.9 x 10^{-10} solar mass per yr to a large, cool and thick disk surrounding a white dwarf, in an orbit with an inclination of 51.6(+/-1.4) degree. Two hotspots on the disk are demonstrated to cause the observed variations in the ellipsoidal modulations from the secondary star. This physical model is compatible with the Gaia distance of KZ Gem.
Peer Review Status:Awaiting Review
Subjects: Physics >> Geophysics, Astronomy, and Astrophysics submitted time 2021-01-24
Abstract: In this paper we re-investigated the relationship between the symmetry of inertial systems and the Lorentz transformation. We found that when we just follow the following three principles: (1)we can define the time in the whole space with a prescribed clock synchronization, (2)the time-space is uniform and the space is isotropic and (3)all the inertial systems are equivalent, then we can totally construct a general coordinate transformation to meet the symmetry of inertial systems, and with a special assumption on the speed of light, we can construct a non-Lorentz transformation between inertial systems to make the particle’s energy have a limited value, which is similar to the rainbow model. Similar to the usual Lorentz violating models, the non-Lorentz transformation in this paper lead to a new modified disperse relation. We applied the obtained disperse relation to analyze the photon’s arrival time lag effect in astronomy and found that the "maximum energy" derived in our model is somewhat related to the "maximum energy" assumed in the rainbow model.
Peer Review Status:Awaiting Review
Subjects: Astronomy >> Astrophysical processes submitted time 2018-06-01 Cooperative journals: 《天文研究与技术》
Abstract:为了对海外站点和无人值守望远镜进行动态监测,判断望远镜是否处于正常的工作状态,提出了一种联合使用天文定位数据和轴系定位数据对望远镜的运行状态进行动态监测的方法。该方法对观测得到的天文定位与轴系定位数据进行误差计算,对比分析两种数据的误差范围,判断望远镜工作状态。利用该方法对亚太地基光学空间物体观测系统(Asia-Pacific Ground-based Optical Space Object Observation System, APOSOS)项目位于伊朗和巴基斯坦的两台15cm地基光电观测望远镜的观测数据进行检验,结果发现:其中1台 15cm望远镜轴系定位中方位角存在较大误差,误差在上百角秒,设备存在问题。通过对比此设备在国内与国外两地观测数据的误差,确定了出现问题的时间和地点。观测站工作人员对望远镜出现问题的报告印证了分析结论,证明了方法的有效性。