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Origin of the cosmic X-ray background: (Invited discourse)

Published online by Cambridge University Press:  14 August 2015

G. Setti  and
M. J. Rees
G. Setti
Affiliation:
Istituto di Fisica ‘A. Righi’, Osservatorio Astronomico Universitario, University of Bologna, Italy
M. J. Rees
Affiliation:
Institute of Theoretical Astronomy, University of Cambridge, England

Abstract

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In this paper we review the theories which have been proposed to account for the extra-galactic X-ray background. Although there is still no detailed theory, one may devise reasonable models which account in a natural way both for the intensity and the spectral shape over the whole energy band, provided that cosmological evolutionary effects are included. A model based on Compton scattering of cosmic black body photons by relativistic electrons in radio sources at large redshifts (z ≳ 4) seems to give the most satisfactory explanation. However, the data are not yet good enough to discriminate against alternative models.

A discussion of the recent observations in the soft X-ray region (< 1 keV), and their relevance to the physics of interstellar and intergalactic gas, is given. The available data are somewhat confusing, but it seems that this part of the spectrum may still be consistent with a simple extrapolation of the non-thermal spectrum at higher energies, though various workers have claimed the detection of a new component probably due to hot intergalactic gas. If this interpretation is correct one may deduce interesting conclusions about the state of ionization and composition of the intergalactic gas, because of the importance of the absorption effects in this energy band.

Also it appears that the Galaxy is more transparent than one would deduce from 21-cm observations. However, due to the lack of observational data, no firm conclusions can be reached.

Type
Research Article
Information
Symposium - International Astronomical Union , Volume 37: Non-Solar X- and Gamma-Ray Astronomy , 1970 , pp. 352 - 371
Copyright
Copyright © Reidel 1970 

References

Allen, C. W.: 1963, Astrophysical Quantities, The Athlone Press, University of London.Google Scholar
Baxter, A. J., Wilson, B. G., and Green, D. W.: 1969, Astrophys. J. 155, L145 (see also paper in this Symposium).Google Scholar
Bell, K. L. and Kingston, A. E.: 1967, Monthly Notices Roy. Astron. Soc. 130, 373.Google Scholar
Bergamini, R., Londrillo, P., and Setti, G.: 1967, Nuovo Cimento 52B, 495.Google Scholar
Boldt, E. and Serlemitsos, P.: 1969, Astrophys. J. 157, 557.Google Scholar
Bowyer, C. S., Field, G. B., and Mack, J. E.: 1968, Nature 217, 32.CrossRefGoogle Scholar
Bowyer, C. S. and Field, G. B.: 1969, Nature 223, 573.Google Scholar
Brecher, K. and Morrison, P., 1967: Astrophys. J. 150, L61.Google Scholar
Brecher, K. and Morrison, P.: 1969, Phys. Rev. Letters 23, 802.CrossRefGoogle Scholar
Bridle, A. H.: 1967a, Monthly Notices Roy. Astron. Soc. 136, 219.Google Scholar
Bridle, A. H.: 1967b, Observatory 87, 263.Google Scholar
Carruthers, G. R.: 1968, Astrophys. J. 151, 269.Google Scholar
Clark, G. W., Garmire, G. P., and Kraushaar, W. L.: 1968, Astrophys. J. 153, L203.Google Scholar
Cooke, B. A., Griffiths, R. E., and Pounds, K. A.: 1969, Nature 224, 134. (See also paper in this volume.)Google Scholar
Davidson, W. and Davies, M.: 1964a, Monthly Notices Roy. Astron. Soc. 127, 241.Google Scholar
Davidson, W. and Davies, M.: 1964b, Monthly Notices Roy. Astron. Soc. 128, 363.Google Scholar
Fazio, G. G.: 1967, Ann. Rev. Astron. Astrophys. 5, 481.Google Scholar
Felten, J. E. and Morrison, P.: 1966, Astrophys. J. 146, 686.Google Scholar
Felten, J. E. and Rees, M. J.: 1969, Nature 221, 924.Google Scholar
Fischel, D. and Stecher, T. P.: 1967, Astrophys. J. 150, L51.Google Scholar
Friedman, H. and Byram, E. T.: 1967, Science 158, 257.Google Scholar
Garmire, G. P. and Kraushaar, W. L.: 1965, Space Sci. Rev. 4, 123.Google Scholar
Ginzburg, V. L. and Syrovatskii, S. I.: 1964a, Usp. Fiz. Nauk. SSSR 84, 201 [transl. Soviet Phys. - Usp. 7, 1965, 696].Google Scholar
Ginzburg, V. L. and Syrovatskii, S. I.: 1964b, Origin of Cosmic Rays, Pergamon Press, Oxford.Google Scholar
Gorenstein, P., Kellog, E. M., and Gursky, H.: 1969, Astrophys. J. 156, 315.Google Scholar
Gould, R. J. and Burbidge, G. R.: 1965, Ann. Astrophys. 28, 171.Google Scholar
Gould, R. J.: 1967, Amer. J. Phys. 35, 376.Google Scholar
Gunn, J. E. and Peterson, B. A.: 1965, Astrophys. J. 142, 1633.Google Scholar
Hayakawa, S. and Matsuoka, M.: 1964, Progr. Theoret. Phys. (Kyoto), Suppl. 30, 204.Google Scholar
Hayakawa, S., Okuda, H., Tanaka, Y., and Yamamoto, Y.: 1964, Progr. Theoret. Physics, Suppl. 30, 153.Google Scholar
Haymes, R. C., Ellis, D. V., Fishman, G. J., Glenn, S. W., and Kurfess, J. D.: 1969, Astrophys. J. 155, L31.Google Scholar
Henry, R. C., Fritz, G., Meekins, J. F., Friedman, H., and Byram, E. T., 1968, Astrophys. J. 153, L11.Google Scholar
Hornby, J. M. and Williams, P. J. S.: 1966, Monthly Notices Roy. Astron. Soc. 131, 237.Google Scholar
Jenkins, E. B. and Morton, D. C.: 1967, Nature 215, 1257.Google Scholar
Kellermann, K. I.: 1966, Astrophys. J. 146, 621.CrossRefGoogle Scholar
Kellermann, K. I. and Pauliny-Toth, I. I. K.: 1969, Astrophys. J. 155, L71.Google Scholar
Lang, K. R. and Terzian, Y.: 1969, Astrophys. Letters 3, 29.Google Scholar
Longair, M. S.: 1966, Monthly Notices Roy. Astron. Soc. 133, 421.CrossRefGoogle Scholar
Longair, M. S. and Sunyaev, R. A.: 1969, preprint No. 84, Lebedev Physical Institute, Moscow.Google Scholar
Low, F. J. and Tucker, W. H.: 1968, Phys. Rev. Lett. 21, 1538.Google Scholar
Mark, H., Price, R., Rodrigues, R., Seward, F. D., and Swift, C. D.: 1969, Astrophys. J. 155, L143.Google Scholar
Morton, D. C.: 1967, Astrophys. J. 147, 1017.Google Scholar
Morton, D. C. and Jenkins, E. B.: 1968, Astron. J. 73, S110.Google Scholar
Oda, M.: 1965, Proc. Int. Conf. Cosmic Rays, London, Vol. I, p. 68.Google Scholar
Oort, J. H.: 1958, ‘La structure et l'évolution de l'Univers’, Brussels, Solvay Conference.Google Scholar
Pooley, G. G. and Ryle, M.: 1968, Monthly Notices Roy. Astron. Soc. 139, 515.Google Scholar
Pottasch, S. R.: 1966, Bull. Astron. Inst. Netherl. 18, 156.Google Scholar
Rees, M. J.: 1967, Monthly Notices Roy. Astron. Soc. 137, 429.Google Scholar
Rees, M. J., Sciama, D. W., and Setti, G.: 1968, Nature 217, 326.Google Scholar
Rees, M. J. and Setti, G.: 1968, Nature 219, 127.Google Scholar
Rowan-Robinson, M.: 1967, Nature 216, 1289.Google Scholar
Rowan-Robinson, M.: 1968, Monthly Notices Roy. Astron. Soc. 138, 445.Google Scholar
Ryle, M.: 1968, Ann. Rev. Astron. Astrophys. 6, 249.Google Scholar
Savedoff, M. P., Hovenier, J. W., and Van Leer, B.: 1967, Bull. Astron. Inst. Netherl. 19, 107.Google Scholar
Sciama, D. W.: 1968, Review paper, presented at the X-Ray Meeting of the Royal Society, London, November 1968. To appear in Phil. Trans. Roy. Soc. Google Scholar
Schmidt, M.: 1966, Astrophys. J. 146, 7.Google Scholar
Schmidt, M.: 1968, Astrophys. J. 151, 393.Google Scholar
Seward, F. D., Chodil, G., Mark, H., Swift, C. D., and Toor, A.: 1967, Astrophys. J. 150, 845.Google Scholar
Shapiro, M. H. and Silberberg, R.: 1968, Proc. 10th Internat. Conf. Cosmic Rays, Calgary, Canadian Jour. Phys. 46, S561.Google Scholar
Shklovskii, I. S.: 1967, Soviet Astron. - A.J. 11, 240.Google Scholar
Shklovskii, I. S.: 1969, Astrophys. Letters 3, 1.Google Scholar
Sholomitskii, G. B.: 1968, Soviet Astron. - AJ 11, 756.Google Scholar
Silk, J.: 1968, Astrophys. J. 151, L19.Google Scholar
Silk, J.: 1969, Nature 221, 347.Google Scholar
Silk, J. and Mc Cray, R.: 1969, Astrophys. Letters 3, 59.Google Scholar
Stecker, F. W.: 1969, Nature 221, 425.Google Scholar
Storer, S. H. and Sciama, D. W.: 1968, Nature 217, 1237.Google Scholar
Sunyaev, R. A.: 1969, Astrophys. Letters 3, 33.Google Scholar
Turtle, A. J. and Baldwin, J. E.: 1962, Monthly Notices Roy. Astron. Soc. 124, 459.Google Scholar
Varshalovich, D. A.: 1967, Soviet Phys. - JETP 25, 157.Google Scholar
Van Bueren, H. G. and Oort, J. H.: 1968, Bull. Astron. Inst. Netherl. 19, 414.Google Scholar
Van Woerden, H.: 1967, in Radio Astronomy and the Galactic System, I.A.U. Symp. No. 31 (ed. by Van Woerden, H.), p. 3.Google Scholar
Véron, P.: 1966a, Nature 211, 724.Google Scholar
Véron, P.: 1966b, Ann. Astrophys. 29, 231.Google Scholar
Weymann, R. J.: 1967, Astrophys. J. 147, 887.Google Scholar
Weymann, R. J.: 1968, in Highlights of Astronomy, I.A.U. Publication (ed. by Perek, L.), Reidel Publ. Comp., Dordrecht, Holland, p. 220.Google Scholar
Williams, P. J. S.: 1966, Nature 210, 285.CrossRefGoogle Scholar