Book reviews

Space Science Reviews -     

Cosmic X-ray observations performed with a gas scintillation spectrometer

Observations of the spectrum of CAS-A in the X-ray energy range 3 to 10 keV have been made using two gas scintillation proportional counters flown on an Aries rocket. Analysis of the data from the 180 second observation has resolved the emission features at 7 keV, which results from transitions in highly ionised iron.     

Space Station Power System

A Space Station Task Force was established by NASA in May 1982 to provide focus and direction for space station planning activities. The Task Force also provides Congress and the Administration with sufficient information to allow them to make an informed decision on whether the United States should proceed with a space station as the next major national initiative in space. This paper presents the status of planning activities to date, with major emphasis on the power system, and discusses technology options, power requirements, and schedule.     

Optical identifications of faint X-ray sources: New CCD candidates for 0918-549, 1822-000 and 1905+000

We present preliminary results of multicolor CCD imaging within the error boxes of several unidentified faint galactic X-ray sources. New, faint ultraviolet stars have been found lying within the combined SAS-3/HEAO A-3 error boxes of Reid et al. (1980) for 0918-549, 1822-000 and the X-ray burster 1905+000.Based on observations collected at the European Southern Observatory, La Silla, Chile.Visiting Astronomer, Canada-France-Hawaii Telescope, administered by NRC of Canada, CNRS of France and U. of Hawaii     

2A0526-328: The white dwarf rotation period revealed

We report results from EXOSAT observations of the intermediate polar system 2A0526-328 (TV Col). The hard X-ray emission (2–8 keV) is modulated with a period of 1943 s, interpreted as the white-dwarf rotation period. Soft and hard X-ray emission show intensity minima, in phase with the orbital period of 0.2286 days; analysis of the hard X-ray spectra shows that these minima are caused by an extra low-energy absorption corresponding to a H column density of 4 × 10²² cm^-2.     

An IR,optical and X-ray study of the two state behaviour of GX 339-4

We review results of correlated IR, optical and X-ray observations of GX 339-4 made from March 1981 through May 1984. In the soft X-ray state, the object does not show outstanding optical and X-ray variability. Night-to-night smooth optical variations of 0.3 magnitudes were however present during one observing run. In contrast, the hard X-ray state is characterised by strong erratic optical and X-ray fluctuations on time scales from 20 milliseconds to seconds, as well as 7 to 20 second quasi-periodic oscillations. The optical counterpart appears much redder in the IR during the hard state. Particular attention is drawn to the hard to soft X-ray transition which occured in June 1981. The shape of the IR to X-ray energy distribution is discussed. The unusual features of this black hole candidate are examined in the framework of the current theories of accretion.Based partly on observations obtained at the European Southern Observatory, La Silla, Chile.     

The sun in the far infrared and sub-mm region

A review is given of the solar radiation between wavelengths of approx. 5 m. and 1 mm. After discussing the astrophysical background (Section 2), we review the brightness temperatures measured in the continuous spectrum in the disk center (Section 3), and compare them with model predictions. The observed limb darkening (or brightening) is described in Section 4, and the line spectrum in Section 5. In Section 6 considerations are given on the usefulness of infrared observations for the investigation of small structures on the Sun.     

Observing the Sun at 20–650 MHz at Thermopylae with Artemis

Fine structure of type IV radio solar bursts with a great variety and complexity often give much information in different ways and enable estimation of various coronal characteristics. In this work, we expose our new method for fine structure revealing and separation of two basic kinds of type IV fine structure, as fibers and pulsations. We also estimate frequency drift of fibers from dynamic spectra, clean from continuous background, with a prototype method using 2-D Fourier transform and we estimate periodicities of fibers as well as pulsations with continuous wavelet transform. Working with the last method we found periodicities close to 3 min umbral oscillations and 5 min global solar oscillations.     

CME Theory and Models

This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1) CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling; (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section on CME initiation three contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can be released violently to drive CMEs. The third model assumes that CMEs can be directly driven by currents from below the photosphere. CMEs evolve considerably as they expand from the magnetically dominated lower corona into the advectively dominated solar wind. The section on evolution and propagation presents two approaches to the problem. One is primarily analytical and focuses on the key physical processes involved. The other is primarily numerical and illustrates the complexity of possible interactions between the CME and the ambient medium. The section on flux rope fitting reviews the accuracy and reliability of various methods. The section on shock formation considers the effect of the rapid decrease in the magnetic field and plasma density with height. Finally, in the section on particle acceleration and transport, some recent developments in the theory of diffusive particle acceleration at CME shocks are discussed. These include efforts to combine self-consistently the process of particle acceleration in the vicinity of the shock with the subsequent escape and transport of particles to distant regions.