共查询到20条相似文献，搜索用时 109 毫秒
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北京天文台１ ．０２ ．０ＧＨｚ 太阳射电频谱仪从１９９４ 年开始观测至１９９８ 年９ 月记录到太阳射电爆发１７１ 个,２ ．６３ ．８ＧＨｚ 太阳射电频谱仪１９９６ 年９ 月投入观测至１９９８ 年９ 月,记录到１４６ 个太阳射电爆发。１９９８ 年４ 月１５ 日太阳射电爆发同时在这两台频谱仪上记录到。这个事件在时间和频率上显示了丰富的幅度和结构的变化。发现了微波Ⅲ型爆发对群,并存在着丰富的快速活动现象。取得了高时间分辨率、高质量的动态谱资料,为研究耀斑各种尺度的时间及空间演化过程提供了丰富的信息。 相似文献
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为完成对太阳射电爆发15 MHz～15 GHz频谱的监测,云南天文台研发4套太阳射电频谱仪,频率覆盖范围依次为15～80 MHz, 100～750 MHz, 600～4 200 MHz和4～15 GHz,分别称为十米波、米波、分米波和厘米波太阳射电频谱仪。十米波段太阳射电频谱仪的谱分辨率和时间分辨率分别为7.6 kHz和1 ms;米波段和分米波段太阳射电频谱仪的谱分辨率和时间分辨率分别为9.5 kHz和10 ms;厘米波段太阳射电频谱仪的谱分辨率和时间分辨率分别为76 kHz和10 ms。每套设备包括天线系统、接收机和数字频谱仪。为实现超高谱分辨率,需要的快速傅里叶变换(Fast Fourier Transform, FFT)点数最高达到262 144,在现场可编程门阵列(Field Programmable Gate Array, FPGA)上,通过一个FFT IP核(Intellectual Property Core)不能实现如此高点数的快速傅里叶变换运算。对于大点数的快速傅里叶变换,需要对数据行列分解后做并行处理,从而将其转化为两个小点数的快速傅里叶变换。通过对并行算法的研究,... 相似文献
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嫦娥四号着陆器将搭载低频射电频谱仪在月球背面进行低频射电天文观测,低频射电频谱仪的观测波段为0.1~40 MHz。根据着陆器在中国空间技术研究院的微波暗室进行的电磁兼容性试验结果,着陆器平台在该频段内自身存在非常强的噪声,其强度甚至淹没大部分来自太阳爆发的信号,难以探测有效信号,实现预期的科学目标。通过模拟仿真分析谱减法、维纳滤波及自适应滤波3种方法对着陆器噪声消除的效果,从而选择更为有效的噪声消除方法,为低频射电频谱仪在轨探测任务的数据处理提供依据。 相似文献
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根据在射电天文频谱观测中出现的新需求,介绍了近年来数字技术的新进展.达到GHz采样速率的多位高速模数转换器(Analog-to-Digital Converter,ADC)、海量数字处理芯片现场可编程门阵列(Field Progxammable Gate Array,FPGA)以及运行在这些芯片上的并行快速傅里叶变换知识产权(Fast Fourier,Transform Intellectual Property,FFT IP)内核,结合高性能数据总线的系统集成,为射电天文构建新型FFT频谱仪提供了可能的技术选择.与现有其他类型频谱仪相比,集成了这些新技术的数字型FFT频谱仪有更大的带宽、更高的谱分辨率、更高的动态范围和整体稳定性,此类频谱仪的出现显示了射电频谱技术已经进入了新一代数字技术应用的阶段. 相似文献
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本文介绍了云南天文台射电室与上海硅酸盐所一室合作在云南天文台进行的声光型射电频谱仪实验,给出了该实验系统的部分参数和实验结果。 相似文献
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本文论述了 0 .7～ 1 .4GHz太阳射电频谱仪数据采集与处理系统是如何实现的。正在研制的此仪器采用了多通道频谱仪与自相关频谱仪结合使用的方案。首先 ,本文详细讨论了自相关频谱仪的原理 ,并介绍了北京大学研制的自相关频谱仪的结构。在此基础上着重讨论了多通道频谱仪与自相关频谱仪的同步控制的解决方案 ,以及大容量数据采集实时存盘的解决方案。最后 ,介绍了我们为数据预处理采用的一些方案。 相似文献
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利用云南天文台声光频谱仪在1991年3月记录到的太阳射电米波辐射事件、光学活动及相关事件作了分析，得到来自6538活动区太阳射电米波事件的一些基本特征。 相似文献
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Recent technical progress of solar radio spectrography is concerned with digital data recording, the achievement of high time and frequency resolution, and with an improved coverage of the radio range at short and long wavelengths. A spatially-distributed network of radio spectrographs allows for complementary information about solar events and periods of activity selected for detailed investigation.By modern radio spectrographs a wealth of not yet adequately classified spectral fine structures can be observed, some of them potentially intimately related to effects of fragmentation of flare energy and/or to processes related to coronal heating. Requirements for the choice of technical parameters of solar spectrographs for checking theoretical models of fundamental processes of energy release are reflected in modern instruments. Prospects for future observations are briefly included. 相似文献
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8~10m级光学／红外望远镜的高分辨率光谱仪 总被引：1，自引：0，他引：1
介绍并比较了KeckSubaruVLTHET及Gemini中的5架8～10m天文望远镜的高分辨率光谱仪,分析这些仪器与2～4m级望远镜的阶梯光栅光谱仪或Coude光谱仪相比所采用的新设计思想和新技术. 相似文献
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The main parameters of spectroscopic experiments in the UV range of the electromagnetic spectrum are estimated. Different spectral devices are compared in terms of their potential quality. Some technical details of current UV experiments and prospects of spectrographs of the WSO-UV project are discussed. 相似文献
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Jorma J. Riihimaa 《Astrophysics and Space Science》1978,56(2):503-518
Dynamic spectra of Jupiter's L-bursts are observed with high-resolution radio spectrographs. The L-bursts are characterized by their emission envelopes. The duration of envelopes varies from one to a few seconds increasing towards the opposition of Jupiter to reach a maximum in the vicinity of 10 to 20 d after opposition. Modulation lanes appear within the emission envelopes. The magnitude of thef-t slopes of lanes is determined by the central meridian longitude (CML) of Jupiter, and partly by the longitude of Io. The sign of the slopes depends on the CML only. The yearly averages for thef-t slopes do not seem to be related to the Jovicentric declination of the Earth. Most lanes are relatively faint. A summary of the properties of modulation lanes is given. A peculiar case of polarization of an L-burst is shown. Certain shadow events are interpreted as occultation effects caused by overdense meteor trails drifting in the upper atmosphere winds. 相似文献
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Comparing the records of the radio spectrographs ARTEMIS (100–500 MHz) on the ground and URAP (1–1000 kHz) on the Ulysses spacecraft, we find that most type III bursts extend from the corona to the solar wind. Using the positions of the associated flares, and assuming an average intensity ratio between these two frequency ranges, we derive for the first time the average radiation pattern of interplanetary type III bursts. We find that at 800 kHz it is shifted east of the radial direction by 30° and has a half-width of about 80° at maximum/10; the shift and width increase towards lower frequencies. Ulysses high-latitude observations show that the cross-section perpendicular to the heliospheric equator is about the same. We interpret these properties by refraction effects in local density gradients. 相似文献
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太阳米波和分米波的射电观测是对太阳爆发过程中耀斑和日冕物质抛射现象研究的重要观测手段。米波和分米波的太阳射电暴以相干等离子体辐射为主导,表现出在时域和频域的多样性和复杂性。其中Ⅱ型射电暴是激波在日冕中运动引起电磁波辐射的结果。在Ⅱ型射电暴方面,首先对米波Ⅱ型射电暴的激波起源问题和米波Ⅱ型射电暴与行星际Ⅱ型射电暴的关系问题进行了讨论;其次,结合Lin-Forbes太阳爆发理论模型对Ⅱ型射电暴的开始时间和起始频率进行讨论:最后,对Ⅱ型射电暴信号中包含的两种射电精细结构,Herringbone结构(即鱼骨结构)和与激波相关的Ⅲ型射电暴也分别进行了讨论。Ⅲ型射电暴是高能电子束在日冕中运动产生电磁波辐射的结果。在Ⅲ型射电暴方面,首先介绍了利用Ⅲ型射电暴对日冕磁场位形和等离子体密度进行研究的具体方法;其次,对利用Ⅲ型射电暴测量日冕温度的最新理论进行介绍;最后,对Ⅲ型射电暴和Ⅱ型射电暴的时间关系、Ⅲ型射电暴和粒子加速以及Ⅲ型射电暴信号中包含的射电精细结构(例如斑马纹、纤维爆发及尖峰辐射)等问题进行讨论并介绍有关的最新研究进展。 相似文献
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N. Kappelmann J. Barnstedt K. Werner H. Becker-Ross S. Florek 《Astrophysics and Space Science》2009,320(1-3):191-195
The World Space Observatory Ultraviolet (WSO/UV) is a multi-national project grown out of the needs of the astronomical community to have future access to the UV range. WSO/UV consists of a single UV telescope with a primary mirror of 1.7 m diameter feeding the UV spectrometer and UV imagers. The spectrometer comprises three different spectrographs, two high-resolution echelle spectrographs (the High-Resolution Double-Echelle Spectrograph, HIRDES) and a low-dispersion long-slit instrument. Within HIRDES the 102–310 nm spectral band is split to feed two echelle spectrographs covering the UV range 174–310 nm and the vacuum-UV range 102–176 nm with high spectral resolution (R>55000). The technical concept is based on the heritage of two previous ORFEUS SPAS missions. The phase-B1 development activities are described in this paper considering the performance of the instruments. 相似文献
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Richard M. McDermid Roland Bacon Harald Kuntschner Eric Emsellem Kristen L. Shapiro Martin Bureau Michele Cappellari Roger L. Davies Jesús Falcn-Barroso Davor Krajnovi&#x; Reynier F. Peletier Marc Sarzi Tim de Zeeuw 《New Astronomy Reviews》2006,49(10-12):521
We summarise the results and achievements of integral-field spectroscopy of early-type galaxies, observed as part of a survey using both the SAURON and OASIS spectrographs. From the perspective of integral-field spectroscopy, these otherwise smooth and featureless objects show a wealth of structure, both in their stellar kinematics and populations. We focus on the stellar content, and examine properties on both kiloparsec scales with SAURON, and scales of 100’s of parsecs with OASIS. These complementary studies reveal two types of kinematically distinct components (KDCs), differing primarily in their intrinsic sizes. In previous studies, KDCs and their host galaxies have generally been found to be unremarkable in other aspects. We show that large KDCs, typical of the well-studied cases, indeed show little or no age differences with their host galaxy. The KDCs detected with the higher spatial-resolution of OASIS are intrinsically smaller and include, in contrast, a significant fraction of young stars. We speculate on the relationship between KDCs and their host galaxies, and the implications for young populations in early-type galaxies. 相似文献