X-Ray Astronomy in the Exosat Era : Proceedings of the XVIII ESLAB Sysmposium, Held in The Hague, The Netherlands, 5–9 November 1984

Algol is a triple system containing a 70 hr eclipsing binary (K IV and B8 V) in a 694 day orbit with an A V star. The X-ray emission from this system (Schnopper et al 1976) is thought to be associated with a corona surrounding the lobe filling and synchron­ ously rotating K IV star. This is based on the similarity of the X-ray spectrum and luminosity of this system to that of the RS CVn binaries which also contain K sub-giants with similar rotation periods and the fact that the luminosity of any coronae surrounding the B8 V and AV companion stars should not be enhanced by rapid rotation (Pallavicini et al 1980, White et al 1980). The Einstein SSS measurement showed the X-ray spectrum to be two component with 6 7 temperatures of 7. 10 K and 3. 10 K (White et al. 1980). As dis­ cussed by Swank et al. (1981), the problem in understanding stellar coronae in general is how to scale up the solar model to account for the enhanced luminosities. The close to 900 inclination and similar sizes for the Band K stars of 3. 6 and 3. 8 R0 respectively make Algol an ideal candidate for an X-ray eclipse measurement wherein the size of the X-ray emitting coronal structures can be directly measured. In this paper we report a continuous observation through the secondary eclipse of Algol using the EXOSAT Observatory. 2. Front Matter....Pages i-xi Front Matter....Pages 1-1 Magnetic Activity in Cool Stars....Pages 3-24 An Exosat Observation of the Morphology of the Coronal X-Ray Emission from Algol....Pages 25-33 Observation of an X-Ray Outburst and Quiescent Emission from the Rs CVn Binary HR1099....Pages 35-41 Exosat Observations of Late-Type Stars: The Application of Coronal Loop Models....Pages 43-49 X-Ray Observations of Active Chromosphere Stars....Pages 51-54 Exosat Observations of the Contact Binary VW Cephei....Pages 55-62 The Extremely X-Ray Bright Wolf-Rayet Star Hd193793....Pages 63-67 EXOSAT Observations of M Dwarfs....Pages 69-72 Exosat Observations of Active Stellar Coronae in the Cygnus Loop, T Tau & NGC 2264 Regions....Pages 73-78 X-Ray Emission from Isolated Hot White Dwarfs....Pages 79-90 X-Ray and Optical Variability at the Hour Timescale for 1E 0630+178 (Geminga) and its Proposed Optical Couterpart....Pages 91-97 X-Ray Emission from Cataclysmic Variables....Pages 99-115 Hard X-Ray Observations of the Eclipsing Binary EX Hydrae....Pages 117-120 2AO526-328: The White Dwarf Rotation Period Revealed....Pages 121-126 SS CYGNI in Outburst and Quiescence....Pages 127-133 Exosat/Optical, Observations of the AM Her Star H0139-68....Pages 135-138 X-Ray Variability of the Am Her Star CW1103+254....Pages 139-141 New Exosat Results from the Intermediate Polar V1223 SGR....Pages 143-149 X-Ray, Optical and UV Observations of the Am Her System E2003+225....Pages 151-155 X-Ray and Optical Observations of Nova Muscae 1983 during its Nebular Stage....Pages 156-156 Front Matter....Pages 1-1 The Discovery of a 25 Min Regular Modulation in the X-Ray Flux From 2S0l42+61....Pages 157-162 The Decay of Dwarf Nova Outbursts....Pages 163-166 The Structure of Low-Mass X-Ray Binaries....Pages 167-194 The Big Dipper: 4U624-49....Pages 195-200 Spectral Variability of Scorpius X-1, as Observed with Exosat....Pages 201-206 High and Medium Resolution Spectroscopy of the X-Ray Transient 4U1543-47....Pages 207-212 An Investigation into the Nature of the 4.4 HR Periodic Source 4U1755-33....Pages 213-217 An IR, Optical and X-Ray Study of the Two State Behaviour of GX 339-4....Pages 219-224 An Exosat Observation of the Peculiar X-Ray Binary 2S 0921-630 During Optical Eclipse....Pages 225-228 LHG 83: Another Outstanding X-Ray Binary in the LMC....Pages 229-232 Exosat Medium Energy Observations of Cyg X-2....Pages 233-238 CCD Photometry of Low Mass X-Ray Binaries: LMCX-2, 1556–60 and 1957+11....Pages 239-243 On Maximum Luminosities of X-Ray Bursts....Pages 245-248 Coordinated Optical-Exosat-Tenma Observations of a Burst from 2S1636-536....Pages 249-253 Exosat and Optical Observations of the X-Ray Burst Source 4U/MXB1636-53....Pages 255-262 Exosat Observations of Bursts from 2S1636-536: Burst Morphology....Pages 263-268 The Quiescent Spectrum of 2S1636-536....Pages 269-273 Exosat Results on the X-Ray Burster 2S1254-690....Pages 275-279 Coordinated Exosat and Optical Observations of the X-Ray Burster 4U1735-44....Pages 281-286 First Detection of an X-Ray Burst and a One Hour Intensity Dip in 4U1323-62....Pages 287-291 Front Matter....Pages 1-1 Detection of Iron Lines in the Persistent Emission of Some X-Ray Burst Sources Observed by Exosat....Pages 293-296 The Variable Iron Line in Cygnus X-3....Pages 297-304 Long Term Observations of CYG X-3 with Vela 5B....Pages 305-311 Cyg X-3 Not Seen at High-Energy Gamma Rays....Pages 313-316 Tenma Observations of Bright Binary X-Ray Sources....Pages 317-338 Temporal Intensity Fluctuations of Her X-1 Around 100 Sec Time Scales....Pages 339-345 35 Day Cycle and the Rotation Period of Her X-1....Pages 347-353 Exosat Observations of the Iron Line Emission of Her X-1 During a 35 Day Cycle....Pages 355-360 Spectra and Time Variability of GX 5–1....Pages 361-365 Exosat Observations of the Bright X- Ray Source Gx9+1....Pages 367-370 LMC X-4: 13.5 Pulsations and an X-Ray Flare Observed by Exosat....Pages 371-377 LMC X-4, AO538-66 and Surrounding X-Ray Sources Observed with Exosat....Pages 379-382 The Discovery of Low-Level Iron Line Emission From Cyg X-1....Pages 383-386 Study of Rapid Variability in Cygnus X-1....Pages 387-390 The Spectral and Temporal Variability of the X-Ray Transient 4U1630-47....Pages 391-398 Intermittent Stellar Wind Accretion in Pop. I Binary Systems Containing An X-Ray Pulsar....Pages 399-407 Be/Neutron Star Binaries: Orbital and Spin Periods....Pages 409-413 The Long Term Variability of 4U 1258-61 (GX304-1)....Pages 415-419 Observation of X-Ray Spectrum of GX301-2....Pages 421-428 Exosat Observations of the X-Ray Pulsar 4U1145-619....Pages 429-432 Front Matter....Pages 1-1 A High Quality Low State Observation of CIR X-1....Pages 433-436 A New View of the Galactic Plane with Exosat....Pages 437-441 Optical Identifications of Faint X-Ray Sources: New CCD Candidates for 0918-549, 1822-000 and 1905+000....Pages 443-445 Galactic Supernova Remnants....Pages 447-465 X-Ray Spectrum of the Tycho SNR Observed with Exosat....Pages 467-474 Exosat PSD and CMA Observations of the SNR PKS 1209-52....Pages 475-480 Mapping of the Cygnus Loop with Exosat....Pages 481-485 Exosat LE-CMA Observations of the Vela Supernova Remnant....Pages 487-493 Some Crucial X-Ray Observations — One or Two SNR(s) in Crux?....Pages 495-501 Soft X-Ray Emission from Radio Loops I and III Compared....Pages 503-506 Synchrotron Nebulae....Pages 507-512 2–10 keV Spectra of Crab-Like SNR’s as Observed by Exosat....Pages 513-519 Spectral Observation of the Composite Supernova Remnant G 29.7 – 0.3....Pages 521-526 Thermal Radiation from a Radio Pulsar PSR 1055-52....Pages 527-529 Extragalactic Supernova Remnants....Pages 531-548 The X-Ray Halo of Cygnus X-1....Pages 549-555 Front Matter....Pages 557-557 X-Ray Timing and Spectral Observations of Active Galactic Nuclei....Pages 559-584 The Soft X-Ray Spectrum of NGC 4151....Pages 585-591 Simultaneous Exosat-IUE Observations of NGC 4151....Pages 593-596 EXOSAT Observations of the BL Lac Object MKN 421....Pages 597-600 Front Matter....Pages 557-557 X-Ray Variability of the Bright BL LAC Object PKS 2155-304....Pages 601-606 Variability of BL LAC Objects at X-RAY and Other Frequencies....Pages 607-612 H0323+022: Classification as a BL LAC and Exosat Coordinated Obsermations....Pages 613-617 MR2251-178: Preliminary Results of an X-Ray Monitoring Programme....Pages 619-622 X-Ray Spectral Variability of 3C273....Pages 623-626 EXOSAT Observation of the QSO Galaxy Pair 1E0104.2+3153....Pages 627-631 EXOSAT Spectra of Some Bright QSO’S....Pages 633-636 The X-ray and Optical Variability of the BLRG 3C390.3....Pages 637-641 An X-Ray Study of M51 (NGC 5194) and its Companion (NGC 5195)....Pages 643-646 Optical Observations of Serendipitous Exosat Sources in the Coma Cluster....Pages 647-652 X-Ray Emission from Clusters of Galaxies....Pages 653-660 EXOSAT 2-10 keV Observations of M87 and the Virgo Cluster....Pages 661-668 Abell 1367 and 1060 Observed with EXOSAT....Pages 669-673 EXOSAT Observations of NGC 1399 and NGC 1404: Two Elliptical Galaxies in the Center of the Fornax Cluster....Pages 675-679 Spectral Constraints on Models of Gas in Clusters of Galaxies....Pages 681-688 Galaxy Clusters: The Missing Mass in Stars....Pages 689-692 Exosat and Einstein High Resolution Images of the Small Magellanic Cloud....Pages 693-699 X-Ray Scattering by Intergalactic Dust....Pages 701-704 Front Matter....Pages 705-705 The Broad Band X-Ray Telescope....Pages 707-714 Possibilities of Investigation of X-Ray Sources on Archival Plates....Pages 715-720 Back Matter....Pages 721-733