以天之语 解物之道

联合国已宣布2009年为国际天文年, 以纪念伽利略开始用望远镜观测天体400周年.作者将400年望远镜和相关技术的发展分为四个里程碑,讲述了它们的出现和随后的发展;介绍了中国已完成的和正在研制中的望远镜,作者支持未来10年中国再上三个大项目; 作者紧密联系天文学和物理学上的重大学说总结了400年天文学的主要成就;作者赞同未来研究的重点应是暗物质和暗能量,尤其是暗能量的研究.     

望远镜和天文学：400年的回顾与展望

联合国已宣布2009年为国际天文年, 以纪念伽利略开始用望远镜观测天体400周年.作者将400年望远镜和相关技术的发展分为四个里程碑,讲述了它们的出现和随后的发展;介绍了中国已完成的和正在研制中的望远镜,作者支持未来10年中国再上三个大项目; 作者紧密联系天文学和物理学上的重大学说总结了400年天文学的主要成就;作者赞同未来研究的重点应是暗物质和暗能量,尤其是暗能量的研究.     

Gravitational wave detectors: New eyes for physics and astronomy

Several interferometric gravitational wave detectors around the world are now starting to achieve better sensitivity to gravitational waves than ever before. We describe the prospects these detectors offer for physics and astronomy and review the rapid progress and the present status of the detectors’ sensitivities. We also report the progress made by the LIGO Scientific Collaboration in analysing the data produced by the LIGO and GEO detectors during the Collaboration’s Science Runs.     

Balloon program for hard-X-ray astronomy

Summary An observation program of X-ray sources in the (20÷200) keV energy band by means of a balloon-borne NaI(Tl) seintillator array was undertaken in 1980. Three balloon flights have been performed and 10 X-ray rources observed, some more than once. We present details of this balloon program and results obtained from the analysis of the Crab observation performed in October 1980. Paper presented at the 2° Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May–June 1984.     

夜天文中的自适应光学

自1989年自适应光学首次在地基天文望远镜上成功实现衍射极限的天文观测以来,自适应光学系统已逐渐发展成为地基大口径天文望远镜必备的仪器之一。由于当今夜天文观测对仪器性能的要求越来越苛刻,为了提高夜天文观测中的适用性,自适应光学系统近20年来也在不断发展,涌现出多种新型自适应光学系统,如激光导星自适应光学系统、多层共轭自适应光学系统、极限自适应光学系统、近地层自适应光学系统等。尽管自适应光学系统的性能不断提高,但仍存在其局限性。文章分析了目前国际上已有自适应光学系统,探讨近年来夜天文当中应用的自适应光学系统及相关进展。     

A scattering polarimeter for X-ray astronomy

Summary We describe a high sensitivity X-ray Thomson polarimeter for astrophysical research, particularly designed for the XMM mission. The efficiency, the modulation factor and the performances of this instrument have been estimated by means of a Monte Carlo simulation. The predicted sensitivity for the high eccentricity Orbit of XMM should allow the detection of the Crab Nebula polarization (3σ, (5÷11)keV) in 15 seconds only. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

TeV astronomy

With the successful realization of the current-generation of ground-based detectors, TeV Astronomy has entered into a new era. We review recent advances in VHE astronomy, focusing on the potential of Imaging Atmospheric Cherenkov Telescopes （IACTs）, and highlight astrophysical implications of the results obtained within recent years.     

Cosmic X-ray astronomy

The results obtained from observations of the celestial x-radiation over the past nine years are reviewed. Emphasis is placed on the study of the discrete sources, particularly those which have been identified with astronomical objects known from optical and radio studies. The isotropic background x-radiation is dealt with briefly, and the theories which account for x-ray production on the astronomical scale are mentioned where applicable. Finally, the observations needed to further advance this exciting subject are discussed.     

Gravitational wave astronomy

We are entering a new era of gravitational-wave astronomy. The ground-based interferometers have reached their initial design sensitivity in the audio band. Several upper limits have been set for anticipated astrophysical sources from the science data. The advanced detectors in the US and in Europe are expected to be operational around 2015. New advanced detectors are also planned in Japan and in India. The first direct detections of gravitational waves are expected within this decade. In the meanwhile, three pulsar timing array projects are forming an international collaboration to detect gravitational waves directly in the nanoHertz range using timing data from millisecond pulsars. The first direct detection of nanoHertz gravitational waves are also expected within this decade. In this paper, we review the status of current gravitational-wave detectors, possible types of sources, observational upper limits achieved, and future prospects for direct detection of gravitational waves     

Large-area phoswich balloon experiment for hard-X-ray astronomy

Summary We describe a balloon experiment, currently in the marking, devoted to the observation of celestial X-ray sources. The main features of the X-ray telescope are summarized as follows. It operates in the energy band from 20 to 300 keV. Its energy resolution is about 17% at 60 keV. Under the hypothesis of 10⁴ s of observing time, 3 mbar of residual atmospheric pressure and 3σ of statistical significance, the expected sensitivity of the instrument is 2·10⁻⁶ photons/cm² s keV in the (20÷200) keV energy band, corresponding to about 1 milliCrab. Its high sensitivity allows us to detect both time variability in the flux and cyclotron lines in the spectra of X-ray sources. It has a field of view of 3° FWHM and has the possibility of resolving complex fields by using multipitch modulation collimators. With such a configuration its angular resolution is about 10′. Paper presented at the 2° Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May–2 June 1984.     

The SAX mission for wide-band X-ray astronomy

Summary In the framework of past and future X-ray missions the SAX satellite, to be launched at the end of 1995, stands out for its very wide spectral coverage from 0.1 to 200 keV. The sensitivity of the scientific payload will also allow the exploitation of the full band of SAX for weak sources (1/20 of 3C273), opening new perspectives in the study of spectral shape and variability of several classes of objects. In this paper we briefly describe the main aspects of the mission, the instruments, the scientific objectives and the operations. Paper presented at the 6th Cosmic Physics National Conference, Palermo, 3–7 November 1992.     

The next detectors for gravitational wave astronomy

This paper focuses on the next detectors for gravitational wave astronomy which will be required after the current ground based detectors have completed their initial observations, and probably achieved the first direct detection of gravitational waves. The next detectors will need to have greater sensitivity, while also enabling the world array of detectors to have improved angular resolution to allow localisation of signal sources. Sect. 1 of this paper begins by reviewing proposals for the next ground based detectors,and presents an analysis of the sensitivity of an 8 km armlength detector, which is proposed as a safe and cost-effective means to attain a 4-fold improvement in sensitivity. The scientific benefits of creating a pair of such detectors in China and Australia is emphasised. Sect. 2 of this paper discusses the high performance suspension systems for test masses that will be an essential component for future detectors, while sect. 3 discusses solutions to the problem of Newtonian noise which arise from fluctuations in gravity gradient forces acting on test masses. Such gravitational perturbations cannot be shielded, and set limits to low frequency sensitivity unless measured and suppressed. Sects. 4 and 5 address critical operational technologies that will be ongoing issues in future detectors. Sect. 4 addresses the design of thermal compensation systems needed in all high optical power interferometers operating at room temperature. Parametric instability control is addressed in sect. 5. Only recently proven to occur in Advanced LIGO, parametric instability phenomenon brings both risks and opportunities for future detectors. The path to future enhancements of detectors will come from quantum measurement technologies. Sect. 6 focuses on the use of optomechanical devices for obtaining enhanced sensitivity, while sect. 7 reviews a range of quantum measurement options.     

TEV gamma-ray astronomy

In the absence of gamma-ray observations from space in the eighties, interest has turned to ground-based observations in the TeV energy region. The best established sources are the Crab Nebula, Cygnus X-3 and Hercules X-1.     

Ground-based gamma-ray astronomy

Summary This report covers developments in the field of gamma-ray astronomy, essentially in the energy range 300 GeV to 300 TeV, reported at the XXIV International Cosmic-Ray Conference in Rome in 1995. Highlights which receive the main attention are the failure of several experiments to detect TeV photons from several supernova remnants at the level predicted on current models of shock acceleration of cosmic-ray protons, and the detection of a rapidly variable flaring output of TeV photons from two BL Lac objects (Markarian 421 and Markarian 501). Although techniques are now maturing to the extent that different measurements of the flux and spectrum from the Crab Nebula are now converging, unresolved differences remain over the existence of TeV pulses from certain pulsars. However, one well-supported instance of very intense pulsation for an hour from AE Aquarii was presented. The Vela Pulsar was reported as a steady source. Rapporteur talk given at the XXIV International Cosmic-Ray Conference, Rome, August 28–September 8, 1995.     

A 110 GHz SIS receiver for radio astronomy

A 110 GHz superconductor insulator superconductor (SIS) tunnel junction receiver has been developed and used in regular astronomical observations on the 4m radio telescope at the Department of Astrophysics, Nagoya University. The SIS junction consists of a sandwich structure of Nb/AlOx/Nb, and is cooled to 4.2K with a closed cycle He-gas refrigerator. The receiver exhibits a best double side band noise temperature of 23±2 K at 110GHz. Additional measurements at 98–115 GHz indicate that the receiver has a good response over this input frequency range.