Hostname: page-component-77c89778f8-m42fx Total loading time: 0 Render date: 2024-07-18T19:39:07.987Z Has data issue: false hasContentIssue false

X-Ray Astronomy

Published online by Cambridge University Press:  06 March 2019

Herbert Friedman*
Affiliation:
Naval Research Laboratory Washington, D. C. 20390
Get access

Abstract

Although searches so far have been restricted to a few small rockets and balloons, some 40 discrete x-ray sources have already been resolved against a diffuse, nearly isotropic background radiation. The strongest source is about 2000 times as bright as the weakest detectable with present rocket instruments. Nearly all of the discrete sources lie close to the galactic plane and most likely are members of the spiral arms of the Milky Way. One x-ray source at high galactic latitude is identifiable with a distant radio galaxy, Virgo A, and its x-ray luminosity is 70 times its radio power. The diffuse background radiation seems to be resolvable into at least two components: one may be associated with the interaction of cosmic rays and the microwave photons of the cosmological 3 K background; the other with bremsstrahlung from hot, intergalactic gas.

Type
Research Article
Copyright
Copyright © International Centre for Diffraction Data 1969

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Friedman, H., Byram, E. T., and Chubb, T. A., “Distribution and Variability of Cosmic X-ray Sources,” Science 156, 374 (1967).Google Scholar
2. Gold, T., “Rotating Neutron Stars and the Nature of Pulsars,” Nature 221, 25 (1969).Google Scholar
3. Hewish, A., Bell, S. J., Pilkington, J. D. H., Scott, P. F., and Collins, R. A., “Observation of a Rapidly Pulsating Radio Source,” Nature 217, 709 (1968).Google Scholar
4. Cocke, W. J., Disney, M. J., and Taylor, D. J., “Discovery of Optical Signals From Pulsar NP 0532,” Nature 221, 525 (1969).Google Scholar
5. Miller, J. S. and Wampler, E. J., “Television Detection of the Crab Nebula Pulsar,” Nature 221, 1037 (1969).Google Scholar
6. Fritz, G., Henry, R. C., Meekins, J. F., Chubb, T. A., and Friedman, H., “X-ray Pulsar in the Crab Nebula,” Science 164, 709 (1969).Google Scholar
7. Bradt, H., Rappaport, S., Mayer, W., Nather, R. E., Warner, B., MacFarlane, M., and Kristian, J., “X-ray and Optical Observations of the Pulsar NP 0532 in the Crab Nebula,” Nature 222, 728 (1969).Google Scholar
8. Fishman, G. J., Harndeu, F. R. Jr., and Hayraes, R. C., “Observations of Pulsed Hard X-Radiation from NP 0532 From 1967 Data,” Astrophys. J. 156, L107 (1969).Google Scholar
9. Rees, M. J., “Proton Synchrotron Emission From Compact Radio Sources,” Astrophys. Lett. 2, 1 (1968).Google Scholar
10. Oke, J. B., “Photoelectric Spectrophotometry of the Crab Pulsating Radio Source NP 0532,” Astrophys. J. Lett. 156, L49 (1969).Google Scholar
11. Meekins, J. F., Henry, R. O., Fritz, G., Friedman, H., and Byram, E. T., “X-ray Spectra of Several Discrete Cosmic Sources,” Astrophys. J. 157, 197 (1969).Google Scholar
12. Manley, O. and Olbert, S., “Models of X-ray Stars,” Astrophys. J. 157, 223 (1969).Google Scholar
13. Fritz, G., Meekins, J. F., Henry, R. C., Byram, E. T., and Friedman, H., “Soft X-rays from Sco XR-1,” Astrophys. J. 153, L199 (1968),Google Scholar
14. Grader, R. J., Hill, R., Seward, F., Toor, A., “X-ray Spectra from Three Cosmic Sources,” Science 152, 1499 (1966).Google Scholar
15. Hill, R. W., Grader, R. J., and Seward, F. D., “The Soft X-ray Spectrum of Sco XR-1,” Astrophys. J. 154, 655 (1968).Google Scholar
16. Rapparport, S., Bradt, H. V., Naranan, S. and Spada, G., “Low-Energy X-ray Spectra of Sco X-l and Four Sagittarius Sources,” Nature 221, 428 (1969).Google Scholar
17. Friedman, H., Byram, E. T., Chubb, T. A., “The Spectrum and Distance of Sco XR-1,” Science 153, 1527 (1966).Google Scholar
18. Angel, J. R. P., Novicky, R., Bout, P. Vanden, and Wolff, R., “Search for X-ray Polarization in Sco X-l,” Phys. Rev. Lett. 22, 861 (1969).Google Scholar
19. Fritz, G., Meekins, J. F., Henry, R. C., and Friedman, H., “On X-ray Line Emission from Sco XR-1,” Astrophys. J. 156, L33 (1969).Google Scholar
20. Tucker, W. H., “Cosmic X-ray Sources,” (Thesis), Univ. Calif., S. Diego, Univ. Microfilm 66-8431 (1966).Google Scholar
21. Gorenstein, P., Gursky, H., and Garmire, G., “The Analysis of X-ray Spectra,” Astrophys. J. 153, 885 (1968).Google Scholar
22. Holt, S. S., Boldt, E. A., and Serlemitsos, P. J., “Iron Line Emission from X-ray Sources,” Astrophys. J. 154, L137 (1968).Google Scholar
23. Hayakawa, S., Matsuoka, M., and Sugimoto, D., “Galactic X-rays,” Space Sci. Rev. 5, 109 (1966).Google Scholar
24. Mandelshtam, S. L. and Tindo, I. P., “Measurement of Diffuse X-ray Background of Outer Space in the Energy Region 1-1.5 keV,” J. Exptl. Theoret. Phys. 6, 796 (1967).Google Scholar
25. Green, D. W., Wilson, B. G., and Baxter, A. J., “A Spectral Measurement of the Cosmic X-ray Background Down to 2 keV,”in Space Research IX, ed. Champion, K. S. W., Smith, P. A. and Smith-Rose, R. L., North- Holland Publishing Co., Amsterdam, 1969, p. 222225.Google Scholar
26. Matsuoka, M., Oda, M., Ogawara, Y., Hayakawa, S., and Kato, T., “Cosmic X-rays,” Proceedings 10th Intl. Conference on Cosmic Rays, Calgary, Canada, Can. J. Phys. (In Press).Google Scholar
27. Seward, F., Chodil, G., Mark, H., Swift, C., and Toor, A., “Diffuse Cosmic X-ray Background Between 4 and 40 KeV,” Astrophys. J. 150, 845 (1967).Google Scholar
28. Boldt, E. A., Desai, U. D., and Holt, S. S., “2-20 kev Spectrum of X-rays from the Crab Nebula and the Diffuse Background Near the Galactic Anticenter,” NASA-GSFC preprint X-611-68-353.Google Scholar
29. Bowyer, C. S., Field, G. B., and Mack, J. E., “Detection of an Anisotropic Soft X-ray Background Flux,” Nature 217, 32 (1968).Google Scholar
30. Henry, R. C., Fritz, G., Meekins, J. F., Friedman, H., and Byrara, E. T., “Possible Detection of a Dense Intergalactic Plasma,” Astrophys. J. 153, L11 (1968).Google Scholar
31. Wilson, B. G., “Cosmic X-ray Background Radiation,” Institute of Space and Aeronautical Science, Univ. Tokyo Report No. 428, Vol. 33, No. 10.Google Scholar