Ebook: Frontiers of Space And Ground-Based Astronomy: The Astrophysics of the 21st Century

ROSAT Observations G. HASINGER Max-Planck-Institut flir extraterrestrische Physik, D-85740 Garching, Germany Abstract. This review describes the most recent advances in the study of the extragalactic soft X-ray background and what we can learn about its constituents. The deepest pointed observations with the ROSAT PSPC are discussed. The logN-logS relation is presented, which reaches to the faintest X-ray fluxes and to the highest AGN surface densities ever achieved. The N(>S) relation shows a 2 density in excess of 400 deg- at the faintest fluxes and a flattening below the Einstein Deep Survey limit. About 60% of the extragalactic background has been resolved in the deepest field. Detailed source spectra and first optical and radio identifications will be discussed. The results are put into perspective of the higher energy X -ray background. Key words: X-rays, background radiations, active galactic nuclei. 1. Introduction The extragalactic X-ray background (XRB), discovered about 30 years ago, has been studied extensively with many X-ray experiments, in particular with the satel­ lites HEAO I and II (see ego Boldt 1987) and with ROSAT (e. g. Hasinger et aI. , 1993). Figure 1 shows a compilation of some of the most recent spectral measure­ ments for the X-ray background. Over the energy range from 3 to about 100 keY its spectrum can be well approximated by an optically thin thermal bremsstrahlung model with kT ~ 40 keY, while at lower X-ray energies a steepening into a new component has been observed observed (e. g.

---

---

Content:
Front Matter....Pages i-xxiii
Front Matter....Pages 1-3
The Gamma-Ray sky According to Compton....Pages 5-16
Comptel view of the Sky in MEV Gamma Rays....Pages 17-22
Galactic Hard X-Ray Sources viewed by Sigma....Pages 23-33
Review of Galactic Center Observations with Granat....Pages 35-46
Highlights of Rosat....Pages 47-51
ASCA and YOHKOH: The Current Generation of Small Japanese Satellites....Pages 53-55
EUV Astronomy with the Rosat wide Field Camera....Pages 57-66
Preliminary Science Results from the Extreme Ultraviolet Explorer....Pages 67-76
15 Years of IUE....Pages 77-86
Highlights of the Hubble Space Telescope....Pages 87-94
The Contribution of Hipparcos to Fundamental Astronomy....Pages 95-104
Recent Results from the Cosmic Background Explorer (COBE)....Pages 105-112
Maintaining the Astronomical Environment for Space Astronomy....Pages 113-120
Front Matter....Pages 121-121
Large Ground-Based Telescopes....Pages 123-127
Ground-Based Infrared Astronomy....Pages 129-132
New Directions for Millimeter Astronomy in the 21st Century....Pages 133-143
Very Long Baseline Interferometry Recent Results and Future Prospects....Pages 145-154
The Importance of Synthesis Radio Telescopes....Pages 155-164
The Maintenance of the Astronomical Environment for Ground Based Astronomy....Pages 165-173
Front Matter....Pages 175-175
A Selection of 10 Most Topical Stellar Problems....Pages 177-186
Front Matter....Pages 175-175
Seismology of the Sun and Stars....Pages 187-200
Star Clusters....Pages 201-210
NOVAE and Other Cataclysmic Variables: Understanding the Effects of Accretion on a White Dwarf....Pages 211-218
Binary Stars in the Era of Space age Astronomy....Pages 219-233
On the Road to Understanding Star Formation....Pages 235-247
Supernovae....Pages 249-263
Neutron Stars and Black Holes in X-Ray Binaries....Pages 265-275
A Review of Pulsar Astronomy....Pages 277-285
Front Matter....Pages 287-287
The ISM within 300 PC and the Nature of the Intercloud Medium....Pages 289-299
Deuterium in the Local Interstellar Medium: Its Cosmological Significance....Pages 301-304
The Magellanic Clouds....Pages 305-314
Structure of Galaxies....Pages 315-323
The International AGN Watch: A Multiwavelength Monitoring Consortium....Pages 325-333
JETS in Active Galactic Nuclei....Pages 335-346
The High Energy Continuum of Agns: Thermal or Non-Thermal?....Pages 347-356
Front Matter....Pages 357-357
Clusters of Galaxies....Pages 359-368
Classical Cosmology....Pages 369-379
The Extragalactic X-Ray Background....Pages 381-394
The Cosmological Evolution of Active Galaxies....Pages 395-407
Gravitational Lensing as a Tool: Future Observational Prospects....Pages 409-419
Front Matter....Pages 421-421
Panel Discussion on Coordination of Observations at Many Wavelengths....Pages 423-432
Front Matter....Pages 433-433
Panel Discussion: New Generation of Large Ground Based Telescopes....Pages 435-446
ESO — VLT Program Status Report....Pages 447-451
The International Stratospheric Laboratory for Astrophysics, Isla....Pages 453-456
Front Matter....Pages 457-457
Panel Discussion: The New Generation Space Telescopes....Pages 459-474
Integral — Fine Spectroscopy and Fine Imaging of Celestial Gamma-Rays....Pages 475-486
Multi-Wavelength Observations with the XMM Observatory....Pages 487-496
Astrophysics with Xspect/Sodart on Spectrum X-Gamma....Pages 497-497
Wide Band X-Ray Astronomy with the Sax Satellite....Pages 499-500
ELF: The European Participation in Lyman-Fuse....Pages 501-504
The Spectrum-UV Project....Pages 505-506
Trust: An Ultraviolet Sky Survey Project....Pages 507-507
An Advanced Camera for the Hubble Space Telescope....Pages 509-512
The Infrared Space Observatory (ISO)....Pages 513-516
The Atlas Sirtf....Pages 517-520
The Edison Space Observatory and the Future of Infrared Astronomy in Space....Pages 521-522
First — Far-Infrared and Submillimetre Space Telescope....Pages 523-524
Front Matter....Pages 525-525
New Technologies for Astronomy....Pages 527-532
The AIPS++ Project....Pages 533-536
Optical Photon Detection Using Superconducting Tunnel Junctions....Pages 537-539
Front Matter....Pages 541-541
Panel Discussion — Summary....Pages 543-548
Front Matter....Pages 549-551
Multi-Waveband Behaviour Of the T Tauri-Star RU Lupi....Pages 553-554
Multiwavelength Study of Protoplanetary Clouds Around Herbig Ae/Be Stars....Pages 555-558
Detection of a Bipolar Flow Associated With UX Ori: An Intermediate-Mass Pre-Main Sequence Star....Pages 559-560
IUE Observations of the Socket Star MT Ori and its Circumstellar Environment....Pages 561-562
The Spectral Energy Distribution and the UV Excess in the Herbig be Candidate HD 45677....Pages 563-564
A Multi-Wavelength Study of WR140 (HD 193793, WC7+04-5) — A Colliding Wind Binary....Pages 565-566
Simultaneous Optical and UV Observations of Wind Variability in O-Type Stars....Pages 567-569
X-Ray Emission from Colliding Stellar Winds....Pages 571-572
Multi-Waveband Behaviour of X-Ray/BE Systems: The Case of A0535+26/HDE 245770....Pages 573-574
Far and Extreme Ultraviolet Spectroscopy of Hot White Dwarf Stars: A Laboratory for Element Diffusion....Pages 575-577
The Ultraviolet Spectrum of an Extremely Metal Deficient Star: HD 52961....Pages 579-580
As 304: Does IUE Discover the Youngest Symbiotic Star?....Pages 581-582
An Atlas of IUE LWR Low Resolution Spectra of K Stars....Pages 583-584
K Stars: Analysis of IUE-LW Fluxes....Pages 585-586
Acoustically Heated Chromospheres in M Dwarfs....Pages 587-588
The Study of the Stellar Activity-Age Correlation in Field Star Samples Through Lithium Abundance Studies....Pages 589-592
Chromospheres in Red Giants....Pages 593-593
Class I Luminosity Functions....Pages 595-595
The Blazhko Effect in RR Lyrae....Pages 597-598
Front Matter....Pages 549-551
A Statistical View of Cataclysmic Variables with the IUE....Pages 599-599
The Interoutburst Behavior of the Recurrent Nova T PYX....Pages 601-604
UV Light Curve of SN1987A....Pages 605-606
A Multiwavelength Study of Stellar Winds in HMXRBs....Pages 607-608
Multi-Wavelength Study of Light Pulsations in the Intermediate Polar H2215-086....Pages 609-609
GX 5-1 with Exosat: How to Become A Z-Source....Pages 611-614
Rapid Infrared Flares in Cygnus X-3....Pages 615-616
Multi-Wavelength Observations of the AM CVn Systems....Pages 617-618
Fast Timing Behaviour of Circinus X-1....Pages 619-620
Line Features in Psds of X-Ray Binaries....Pages 621-622
Radio Observations of Transient Gamma Ray Sources with the Westerbork Array....Pages 623-627
Rosat Observations of Young Stellar Clusters....Pages 629-630
Are There two Populations of Blue Straggler Stars in the Globular Cluster M3?....Pages 631-631
Hot Stars in the Core of 47 TUC from NTT and HST Observations....Pages 633-637
Blue Straggler Stars in the Inner Region of the Globular Cluster M 15....Pages 639-639
Front Matter....Pages 641-641
HST Observations of Ultraviolet Interstellar Polarization....Pages 643-643
High Resolution Spectra with HST Of Shocked Clouds in the Vela Remnant....Pages 645-647
CNO Abundances in High-Redshift Absorption Line Systems of the QSO HS 1700 + 6416....Pages 649-650
The Lyman ? Forest and the Universal Bubble Structure....Pages 651-652
HST Spectra of Stellar Populations: The Extinction Law and IMF in M 101....Pages 653-653
Front Matter....Pages 641-641
IUE/HST-FOC Search for Hot Stars in Nearby Galaxies....Pages 655-656
Eclipsing Binaries as Accurate Distance Indicators to Nearby Galaxies....Pages 657-658
The Impact of High Resolution UV Imaging on Stellar Astrophysics....Pages 659-659
Globular Clusters in M31 with the Hubble Space Telescope....Pages 661-661
HST/FOS UV-Spectroscopy of Weak Radio Galaxies At z = 0.1-0.6....Pages 663-667
High-Redshift Radio Galaxies with the HST....Pages 669-671
The Lockman Hole: Radio Identification of Very Faint Rosat Sources....Pages 673-673
VLBI Observations of Radio Galaxies....Pages 675-676
The Medium-Deep Survey Using the Hubble Space Telescope....Pages 677-679
The X-Ray Spectra of Blazars: Analysis of the Complete Exosat Archive....Pages 681-683
Active Galactic Nuclei Across the Electromagnetic Spectrum....Pages 685-686
Multifrequency Spectra of Blazars....Pages 687-690
UV/Optical Microvariability in Seyfert Galaxies....Pages 691-692
Multiwavelength Evolution of the 1991 Outburst of 3C 345....Pages 693-694
Simultaneous Rosat, Ginga, VLA, IUE, and Optical Observations of the Bright Quasar H1821 + 643....Pages 695-695
Front Matter....Pages 697-697
Ultra Heavy Cosmic Ray Measurements on the LDEF Satellite and the Merging of Multi-Waveband and Particle Astronomy....Pages 699-702
A Very Large Area Telescope for ?-Ray Astronomy Above 100 MeV Employing Limited Streamer Tubes....Pages 703-704
Very High Energy Gamma-Ray Astronomy with Ground-Based Imaging Cherenkov Telescopes....Pages 705-706
Hard X-Ray Concentration for Future Space Astronomy Missions....Pages 707-708
The Evolution of the IUE Archive....Pages 709-713
Front Matter....Pages 697-697
The IUE Final Archive: Conception to Completion....Pages 715-716
The Hexa-Pod-Telescope: The Mounting....Pages 717-718
The Hexa-Pod-Telescope: The Optical Telescope Assembly....Pages 719-720
The Optical Science and Technology Centre at Bochum — A New Partner for Observational Astronomy....Pages 721-722
A 690 GHZ SIS Mixer....Pages 723-724
The European Space Information System....Pages 725-727
Back Matter....Pages 729-750

---

Content:
Front Matter....Pages i-xxiii
Front Matter....Pages 1-3
The Gamma-Ray sky According to Compton....Pages 5-16
Comptel view of the Sky in MEV Gamma Rays....Pages 17-22
Galactic Hard X-Ray Sources viewed by Sigma....Pages 23-33
Review of Galactic Center Observations with Granat....Pages 35-46
Highlights of Rosat....Pages 47-51
ASCA and YOHKOH: The Current Generation of Small Japanese Satellites....Pages 53-55
EUV Astronomy with the Rosat wide Field Camera....Pages 57-66
Preliminary Science Results from the Extreme Ultraviolet Explorer....Pages 67-76
15 Years of IUE....Pages 77-86
Highlights of the Hubble Space Telescope....Pages 87-94
The Contribution of Hipparcos to Fundamental Astronomy....Pages 95-104
Recent Results from the Cosmic Background Explorer (COBE)....Pages 105-112
Maintaining the Astronomical Environment for Space Astronomy....Pages 113-120
Front Matter....Pages 121-121
Large Ground-Based Telescopes....Pages 123-127
Ground-Based Infrared Astronomy....Pages 129-132
New Directions for Millimeter Astronomy in the 21st Century....Pages 133-143
Very Long Baseline Interferometry Recent Results and Future Prospects....Pages 145-154
The Importance of Synthesis Radio Telescopes....Pages 155-164
The Maintenance of the Astronomical Environment for Ground Based Astronomy....Pages 165-173
Front Matter....Pages 175-175
A Selection of 10 Most Topical Stellar Problems....Pages 177-186
Front Matter....Pages 175-175
Seismology of the Sun and Stars....Pages 187-200
Star Clusters....Pages 201-210
NOVAE and Other Cataclysmic Variables: Understanding the Effects of Accretion on a White Dwarf....Pages 211-218
Binary Stars in the Era of Space age Astronomy....Pages 219-233
On the Road to Understanding Star Formation....Pages 235-247
Supernovae....Pages 249-263
Neutron Stars and Black Holes in X-Ray Binaries....Pages 265-275
A Review of Pulsar Astronomy....Pages 277-285
Front Matter....Pages 287-287
The ISM within 300 PC and the Nature of the Intercloud Medium....Pages 289-299
Deuterium in the Local Interstellar Medium: Its Cosmological Significance....Pages 301-304
The Magellanic Clouds....Pages 305-314
Structure of Galaxies....Pages 315-323
The International AGN Watch: A Multiwavelength Monitoring Consortium....Pages 325-333
JETS in Active Galactic Nuclei....Pages 335-346
The High Energy Continuum of Agns: Thermal or Non-Thermal?....Pages 347-356
Front Matter....Pages 357-357
Clusters of Galaxies....Pages 359-368
Classical Cosmology....Pages 369-379
The Extragalactic X-Ray Background....Pages 381-394
The Cosmological Evolution of Active Galaxies....Pages 395-407
Gravitational Lensing as a Tool: Future Observational Prospects....Pages 409-419
Front Matter....Pages 421-421
Panel Discussion on Coordination of Observations at Many Wavelengths....Pages 423-432
Front Matter....Pages 433-433
Panel Discussion: New Generation of Large Ground Based Telescopes....Pages 435-446
ESO — VLT Program Status Report....Pages 447-451
The International Stratospheric Laboratory for Astrophysics, Isla....Pages 453-456
Front Matter....Pages 457-457
Panel Discussion: The New Generation Space Telescopes....Pages 459-474
Integral — Fine Spectroscopy and Fine Imaging of Celestial Gamma-Rays....Pages 475-486
Multi-Wavelength Observations with the XMM Observatory....Pages 487-496
Astrophysics with Xspect/Sodart on Spectrum X-Gamma....Pages 497-497
Wide Band X-Ray Astronomy with the Sax Satellite....Pages 499-500
ELF: The European Participation in Lyman-Fuse....Pages 501-504
The Spectrum-UV Project....Pages 505-506
Trust: An Ultraviolet Sky Survey Project....Pages 507-507
An Advanced Camera for the Hubble Space Telescope....Pages 509-512
The Infrared Space Observatory (ISO)....Pages 513-516
The Atlas Sirtf....Pages 517-520
The Edison Space Observatory and the Future of Infrared Astronomy in Space....Pages 521-522
First — Far-Infrared and Submillimetre Space Telescope....Pages 523-524
Front Matter....Pages 525-525
New Technologies for Astronomy....Pages 527-532
The AIPS++ Project....Pages 533-536
Optical Photon Detection Using Superconducting Tunnel Junctions....Pages 537-539
Front Matter....Pages 541-541
Panel Discussion — Summary....Pages 543-548
Front Matter....Pages 549-551
Multi-Waveband Behaviour Of the T Tauri-Star RU Lupi....Pages 553-554
Multiwavelength Study of Protoplanetary Clouds Around Herbig Ae/Be Stars....Pages 555-558
Detection of a Bipolar Flow Associated With UX Ori: An Intermediate-Mass Pre-Main Sequence Star....Pages 559-560
IUE Observations of the Socket Star MT Ori and its Circumstellar Environment....Pages 561-562
The Spectral Energy Distribution and the UV Excess in the Herbig be Candidate HD 45677....Pages 563-564
A Multi-Wavelength Study of WR140 (HD 193793, WC7+04-5) — A Colliding Wind Binary....Pages 565-566
Simultaneous Optical and UV Observations of Wind Variability in O-Type Stars....Pages 567-569
X-Ray Emission from Colliding Stellar Winds....Pages 571-572
Multi-Waveband Behaviour of X-Ray/BE Systems: The Case of A0535+26/HDE 245770....Pages 573-574
Far and Extreme Ultraviolet Spectroscopy of Hot White Dwarf Stars: A Laboratory for Element Diffusion....Pages 575-577
The Ultraviolet Spectrum of an Extremely Metal Deficient Star: HD 52961....Pages 579-580
As 304: Does IUE Discover the Youngest Symbiotic Star?....Pages 581-582
An Atlas of IUE LWR Low Resolution Spectra of K Stars....Pages 583-584
K Stars: Analysis of IUE-LW Fluxes....Pages 585-586
Acoustically Heated Chromospheres in M Dwarfs....Pages 587-588
The Study of the Stellar Activity-Age Correlation in Field Star Samples Through Lithium Abundance Studies....Pages 589-592
Chromospheres in Red Giants....Pages 593-593
Class I Luminosity Functions....Pages 595-595
The Blazhko Effect in RR Lyrae....Pages 597-598
Front Matter....Pages 549-551
A Statistical View of Cataclysmic Variables with the IUE....Pages 599-599
The Interoutburst Behavior of the Recurrent Nova T PYX....Pages 601-604
UV Light Curve of SN1987A....Pages 605-606
A Multiwavelength Study of Stellar Winds in HMXRBs....Pages 607-608
Multi-Wavelength Study of Light Pulsations in the Intermediate Polar H2215-086....Pages 609-609
GX 5-1 with Exosat: How to Become A Z-Source....Pages 611-614
Rapid Infrared Flares in Cygnus X-3....Pages 615-616
Multi-Wavelength Observations of the AM CVn Systems....Pages 617-618
Fast Timing Behaviour of Circinus X-1....Pages 619-620
Line Features in Psds of X-Ray Binaries....Pages 621-622
Radio Observations of Transient Gamma Ray Sources with the Westerbork Array....Pages 623-627
Rosat Observations of Young Stellar Clusters....Pages 629-630
Are There two Populations of Blue Straggler Stars in the Globular Cluster M3?....Pages 631-631
Hot Stars in the Core of 47 TUC from NTT and HST Observations....Pages 633-637
Blue Straggler Stars in the Inner Region of the Globular Cluster M 15....Pages 639-639
Front Matter....Pages 641-641
HST Observations of Ultraviolet Interstellar Polarization....Pages 643-643
High Resolution Spectra with HST Of Shocked Clouds in the Vela Remnant....Pages 645-647
CNO Abundances in High-Redshift Absorption Line Systems of the QSO HS 1700 + 6416....Pages 649-650
The Lyman ? Forest and the Universal Bubble Structure....Pages 651-652
HST Spectra of Stellar Populations: The Extinction Law and IMF in M 101....Pages 653-653
Front Matter....Pages 641-641
IUE/HST-FOC Search for Hot Stars in Nearby Galaxies....Pages 655-656
Eclipsing Binaries as Accurate Distance Indicators to Nearby Galaxies....Pages 657-658
The Impact of High Resolution UV Imaging on Stellar Astrophysics....Pages 659-659
Globular Clusters in M31 with the Hubble Space Telescope....Pages 661-661
HST/FOS UV-Spectroscopy of Weak Radio Galaxies At z = 0.1-0.6....Pages 663-667
High-Redshift Radio Galaxies with the HST....Pages 669-671
The Lockman Hole: Radio Identification of Very Faint Rosat Sources....Pages 673-673
VLBI Observations of Radio Galaxies....Pages 675-676
The Medium-Deep Survey Using the Hubble Space Telescope....Pages 677-679
The X-Ray Spectra of Blazars: Analysis of the Complete Exosat Archive....Pages 681-683
Active Galactic Nuclei Across the Electromagnetic Spectrum....Pages 685-686
Multifrequency Spectra of Blazars....Pages 687-690
UV/Optical Microvariability in Seyfert Galaxies....Pages 691-692
Multiwavelength Evolution of the 1991 Outburst of 3C 345....Pages 693-694
Simultaneous Rosat, Ginga, VLA, IUE, and Optical Observations of the Bright Quasar H1821 + 643....Pages 695-695
Front Matter....Pages 697-697
Ultra Heavy Cosmic Ray Measurements on the LDEF Satellite and the Merging of Multi-Waveband and Particle Astronomy....Pages 699-702
A Very Large Area Telescope for ?-Ray Astronomy Above 100 MeV Employing Limited Streamer Tubes....Pages 703-704
Very High Energy Gamma-Ray Astronomy with Ground-Based Imaging Cherenkov Telescopes....Pages 705-706
Hard X-Ray Concentration for Future Space Astronomy Missions....Pages 707-708
The Evolution of the IUE Archive....Pages 709-713
Front Matter....Pages 697-697
The IUE Final Archive: Conception to Completion....Pages 715-716
The Hexa-Pod-Telescope: The Mounting....Pages 717-718
The Hexa-Pod-Telescope: The Optical Telescope Assembly....Pages 719-720
The Optical Science and Technology Centre at Bochum — A New Partner for Observational Astronomy....Pages 721-722
A 690 GHZ SIS Mixer....Pages 723-724
The European Space Information System....Pages 725-727
Back Matter....Pages 729-750
....