Extreme Ultraviolet Astronomy

EXTREME ULTRAVIOLET ASTRONOMY......Page 1
About......Page 2
Cambridge Astrophysics Series......Page 4
Title Page......Page 6
Copyright Page......Page 7
Dedication......Page 8
Contents......Page 10
Preface......Page 14
Abbreviations......Page 16
1.1 Astrophysical significance of the EUV......Page 20
1.2 The ‘unobservable ultraviolet’......Page 22
1.3 Early detectors for the EUV......Page 24
1.3.1 Proportional counters......Page 25
1.3.2 Photomultipliers and channel electron multipliers......Page 26
1.4 Early experiments with sounding rockets......Page 27
1.5 EUV astronomy on the Apollo–Soyuz mission......Page 28
1.6 After Apollo–Soyuz......Page 30
1.7.1 Geocoronal background......Page 33
1.7.2 The cosmic EUV background......Page 34
2.2.1 A physical understanding of emission processes......Page 36
2.2.2 Stellar photospheres......Page 37
2.2.3 Stellar coronae......Page 39
2.3 Grazing incidence mirror technology......Page 40
2.4 Applications of grazing incidence technology in space......Page 42
2.5 Detector technology for space missions......Page 46
2.5.1 Position encoding systems for detectors......Page 49
2.5.2 Photocathode materials for MCP detectors......Page 51
2.6 Thin film filters......Page 53
2.7 Selected scientific results from Einstein and EXOSAT......Page 56
2.7.1 Photometry and spectroscopy of white dwarfs......Page 57
2.7.2.1 RS CVns: the first class of coronal sources......Page 63
2.7.2.2 Coronal surveys and rotation......Page 64
2.7.2.5 Binary systems......Page 66
2.7.3 EUV photometric observations of CVs with Einstein and EXOSAT......Page 67
2.8 Far-UV spectroscopy with IUE......Page 69
2.9 EUV and far-UV spectroscopy with Voyager......Page 72
3.1 Introduction......Page 76
3.2 The ROSAT mission......Page 77
3.2.1 The X-ray telescope......Page 78
3.3.1 WFC mirrors......Page 82
3.3.2 MCP detectors for the WFC......Page 83
3.3.3 Thin film filters......Page 85
3.3.4 ROSAT sky survey strategy......Page 86
3.4 Highlights from the WFC EUV sky survey......Page 87
3.4.1 A new source at ‘first light’......Page 88
3.4.2 First detection of a stellar flare in the EUV......Page 89
3.4.3 Optical, EUV and X-ray oscillations in V471 Tauri......Page 90
3.5.1 The catalogues......Page 92
3.5.2 Identification of EUV sources......Page 93
3.5.2.1 WFC source names......Page 95
3.6.1 Composition and luminosity of DA white dwarfs in the EUV......Page 96
3.6.2 The nature of the photospheric opacity in DA white dwarfs......Page 101
3.6.3 The mass distribution of the EUV selected sample of white dwarfs......Page 102
3.7 Hidden white dwarfs in binary systems......Page 106
3.8.1 EUV luminosity functions and the nearby stellar sample......Page 110
3.8.2 Kinematic properties of EUV selected active late-type stars......Page 123
3.8.3 Cataclysmic variables......Page 124
3.8.4 EUV emission from active galactic nuclei......Page 127
3.9 The interstellar medium......Page 128
3.9.1 A search for the signature of the diffuse background......Page 129
3.9.2 Structure of the local ISM......Page 130
4.1.1 The telescopes......Page 134
4.1.2 The thin film bandpass filters......Page 136
4.1.3 The detectors......Page 138
4.1.4 The overall performance of the EUVE imaging telescopes......Page 139
4.2 The EUVE all-sky survey......Page 142
4.2.1 The Right Angle Program......Page 143
4.2.2 Comparison of the WFC and EUVE sky surveys......Page 144
4.3.1 Science with the long wavelength filters......Page 147
4.3.2 Hot white dwarfs......Page 149
4.3.3 Observations of the Moon......Page 150
4.3.4 Isolated neutron stars......Page 151
4.3.5 EUV emission from classical novae......Page 154
4.3.6 Activity in late-type stars......Page 155
4.3.7 Extragalactic objects......Page 159
4.3.8 Shadowing of the EUVE background......Page 162
4.4 The ALEXIS mission......Page 164
4.4.2 The ALEXIS scientific payload......Page 165
4.4.4 ALEXIS in-orbit loss and recovery......Page 167
4.4.5.1 The diffuse EUV background......Page 168
4.4.5.3 Transient phenomena......Page 169
4.4.5.5 Obervations of the Moon......Page 172
5.2 The Extreme Ultraviolet Explorer spectrometer......Page 174
5.3 Spectral analysis techniques......Page 177
5.4 Theoretical spectral models......Page 179
5.4.2 Plasma codes and emission line analyses......Page 180
5.4.3 The emission measure and its distribution......Page 181
5.4.4 What is needed to analyse EUV spectra?......Page 184
5.4.5 Plasma codes for data analysis......Page 185
5.4.6 Abundance measurements and the FIP effect......Page 188
5.5 EUV spectroscopy with other instruments......Page 189
6.1 Emission from B stars......Page 192
6.2 ε Canis Majoris......Page 193
6.2.1 Absorption lines in the spectrum of ε CMa......Page 196
6.2.2 Emission lines......Page 200
6.2.3 The wind and the high energy flux from ε CMa......Page 201
6.3 Observations of β CMa......Page 204
6.4 Coronal sources – the stellar zoo......Page 206
6.5.1 Procyon......Page 210
6.5.2 ε Eridani......Page 214
6.5.3 α Centauri......Page 218
6.5.4 Other solar-like stars......Page 222
6.6 Active systems......Page 226
6.6.1 Capella: a reference point in the analysis of active stars?......Page 227
6.6.2 Coronal element abundances in RS CVn systems......Page 230
6.7 Contact and short period binaries......Page 239
6.8 The effect of stellar activity on EUV spectra......Page 240
6.9 Giants and the Hertzsprung gap......Page 245
6.10 Physical models......Page 246
7.2 Spectral observations of the diffuse background......Page 252
7.3 Interstellar He II and autoionisation of He in the ISM......Page 255
7.4 Interstellar absorption by hydrogen and helium......Page 257
7.5.1 The helium ionisation fraction along the line-of-sight to GD246......Page 259
7.6.2 Spectroscopic studies of interstellar absorption......Page 260
8.1 The importance of EUV spectra of white dwarfs......Page 270
8.2 Measuring effective temperature from EUV continua......Page 271
8.3.1 Isolated DA white dwarfs......Page 275
8.3.2 White dwarfs in binaries......Page 278
8.3.3 Comments on the role of He in hot DA white dwarfs......Page 283
8.4.1 Limits on heavy element abundances in ‘pure H’ white dwarfs......Page 285
8.4.2 White dwarfs with intermediate heavy element opacity......Page 290
8.4.3 White dwarfs with extreme heavy element opacities......Page 295
8.4.4 Heavy element stratification......Page 306
8.4.5 The hot H-rich CSPN NGC 1360......Page 309
8.5.1 The temperature range of the GW Vir instability strip......Page 310
8.5.2 The composition and temperature of REJ0503–289......Page 312
8.5.3 The cool DO white dwarf HD149499B......Page 313
8.6 White dwarfs in binary systems with B star companions......Page 315
9.1 Emission mechanisms in CVs......Page 320
9.2 Spectral modelling......Page 322
9.3 EUVE spectroscopy of magnetic CVs......Page 325
9.4 Non-magnetic CVs......Page 330
9.5 Intermediate polars......Page 331
9.6 Summary......Page 334
10.1 Active galaxies......Page 336
10.2 Extragalactic source variability......Page 340
11.1 Looking back......Page 344
11.3 New EUV science......Page 345
11.3.2 High resolution EUV spectroscopy......Page 346
11.3.5 Cataclysmic variables and related objects......Page 347
11.3.6 Interstellar medium......Page 348
11.3.7 Requirements for new EUV instrumentation......Page 349
11.4.1 The Joint Plasmadynamic Experiment......Page 350
11.5 Concluding remarks......Page 354
Appendix. A merged catalogue of Extreme Ultraviolet sources......Page 356
Table A.1. All-sky survey source list with position information and optical identification, together with spectral type and visual magnitude where appropriate......Page 357
Table A.2. All-sky survey source list with count rates (in counts per 1000 seconds) in the WFC S1, WFC S2, EUVE 100 Å, EUVE 200 Å, EUVE 400 Å and EUVE 600 Å filters.......Page 373
Table A.3. Composite EUVE deep survey source list; c and d are the Deep Survey 100 Å and 200 Å bands respectively......Page 389
References......Page 392
Index......Page 406