Hostname: page-component-5c6d5d7d68-xq9c7 Total loading time: 0 Render date: 2024-08-17T00:13:05.123Z Has data issue: false hasContentIssue false
  • English
  • Français

Theories of discrete X-ray and γ-ray sources: (Invited discourse)

Published online by Cambridge University Press:  14 August 2015

James E. Felten
James E. Felten*
Affiliation:
Institute of Theoretical Astronomy, University of Cambridge, England

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

This is a critical review of theories of known discrete X-ray sources. The Crab is omitted, having been dealt with in Woltjer's review. Two of the identified sources, Sco X-1 and Cyg X-2, seem to be of the same sort. A binary or gas-stream model like that of Prendergast and Burbidge, with dimension R ∼ 109 cm and density n ∼ 1016 cm−3, appears reconcilable with the observed features of these sources, though much detailed work remains to be done. Neither object is yet known to be binary. Theoretical work becomes more difficult if, as appears to be the case at least for Sco X-1, the objects are optically thick due to electron scattering; this may affect the optical and X-ray spectra.

The recent searches for iron lines in the X-ray spectrum of Sco X-1 are reviewed briefly. The calculations and the energy resolution are not yet good enough to make this a dependable test of models.

Several possibilities are offered for explaining the excess radio flux from Sco X-1.

Other theories of Sco X-1-type sources are discussed briefly. The theory of Manley and Olbert seems a little superfluous when the gas-stream theory is still in a strong position.

There are serious discrepancies between X-ray and optical estimates of the distance to Sco X-1. 21-cm measurements must also be considered. The situation is reviewed, and ways out of the difficulty are discussed.

Cen X-2 seems to be like Sco X-1, but several other unidentified sources have hard spectra like the Crab. It is tempting to speculate that most of the galactic sources are supernova remnants.

The extended γ-ray source in the galactic plane may be the extrapolated unresolved sum of galactic X-ray sources, as suggested by Ogelman. There are several other possibilities.

M87 is the only established extragalactic source. Radio, optical and X-ray observations are summarized and graphed. A power-law extrapolation to the X-ray band is far from mandatory; nevertheless the optical flux from the jet is known to be synchrotron radiation. The time-scale difficulties in the jet are described, and several theories of the survival of the optical electrons are reviewed.

Processes for producing X-rays other than thermal bremsstrahlung and synchrotron radiation are listed. These other processes are characterized by low efficiency, and are likely to be unimportant in discrete sources, though several have attracted attention with reference to the diffuse background.

Type
Research Article
Information
Symposium - International Astronomical Union , Volume 37: Non-Solar X- and Gamma-Ray Astronomy , 1970 , pp. 216 - 237
Copyright
Copyright © Reidel 1970 

References

Ables, J. G.: 1969, Astrophys. J. (Lett.) 155, L27.Google Scholar
Adams, D. J., Cooke, B. A., Evans, K., and Pounds, K. A.: 1969, Nature 222, 757.Google Scholar
Aller, L. H.: 1961, Abundance of the Elements, Interscience Publishers, New York, pp. 179ff.Google Scholar
Angel, J. R. P.: 1969, Nature 224, 160.Google Scholar
Apparao, M. V. K.: 1967, Proc. Ind. Acad. Sci. A66, 55.Google Scholar
Arp, H. C.: 1967, Astrophys. Lett. 1, 1.Google Scholar
Bell, K. L. and Kingston, A. E.: 1967, Monthly Notices Roy. Astron. Soc. 136, 241.Google Scholar
Biermann, L.: 1969, Proc. Roy. Soc. A 313, 357.Google Scholar
Boldt, E. A. and Serlemitsos, P. A.: 1969, Astrophys. J. 157, 557.Google Scholar
Bradt, H., Mayer, W., Naranan, S., Rappaport, S., and Spada, G.: 1967, Astrophys. J. (Lett.) 150, L199.CrossRefGoogle Scholar
Burbidge, G. R.: 1956, Astrophys. J. 124, 416.Google Scholar
Burbidge, G.: 1967a, Nature 216, 1287.Google Scholar
Burbidge, G. R.: 1967b, in IAU Symposium No. 31, Radio Astronomy and the Galactic System (ed. by van Woerden, H.), Academic Press, London, p. 463.Google Scholar
Burbidge, G.: 1968, paper read at Royal Society. Proc. Roy. Soc. A313, 331 (1969).Google Scholar
Burbidge, G. and Hoyle, F.: 1969, Nature 221, 847.Google Scholar
Buselli, G., Clancy, M. C., Davison, P. J. N., Edwards, P. J., McCracken, K. G., and Thomas, R. M.: 1968, Nature 219, 1124.CrossRefGoogle Scholar
Byram, E. T., Chubb, T. A., and Friedman, H.: 1966, Science 152, 66.Google Scholar
Cameron, A. G. W.: 1969, Astrophys. Lett. 3, 171.Google Scholar
Cameron, A. G. W. and Mock, M.: 1967, Nature 215, 464.Google Scholar
Charman, W. N., Jelley, J. V., Orman, P. R., Drever, R. W. P., and McBreen, B.: 1968, Nature 220, 565.Google Scholar
Chodil, G., Mark, H., Rodrigues, R., Seward, F. D., Swift, C. D., Turiel, I., Hiltner, W. A., Wallerstein, G., and Mannery, E. J.: 1968, Astrophys. J. 154, 645.Google Scholar
Clark, G. W., Garmire, G. P., and Kraushaar, W. L.: 1968, Astrophys. J. (Lett.) 153, L203.CrossRefGoogle Scholar
Cowsik, R. and Pal, Y.: 1969, Phys. Rev. Lett. 22, 550.Google Scholar
De Vaucouleurs, G., Angione, R., and Fraser, C. W.: 1968, Astrophys. Lett. 2, 141.Google Scholar
Eggen, O. J., Freeman, K. C., and Sandage, A.: 1968, Astrophys. J. (Lett.) 154, L27.Google Scholar
Fegan, D. J., McBreen, B., O'Mongain, E. P., Porter, N. A., and Slevin, P. J.: 1968, Canadian J. Phys. 46, S433.Google Scholar
Feldman, P. A. and Silk, J. I.: 1970, this volume, p. 257.Google Scholar
Felten, J. E.: 1968, Astrophys. J. 151, 861.CrossRefGoogle Scholar
Felten, J. E. and Gould, R. J.: 1966, Phys. Rev. Lett. 17, 401.Google Scholar
Felten, J. E. and Rees, M. J.: 1969, Nature 221, 924.Google Scholar
Felten, J. E., Arp, H. C., and Lynds, C. R.: 1970, Astrophys. J. (in press).Google Scholar
Friedlander, M. W.: c. 1962, unpublished work.Google Scholar
Friedman, H. and Byram, E. T.: 1967, Science 158, 257.Google Scholar
Fritz, G., Meekins, J. F., Henry, R. C., Byram, E. T., and Friedman, H.: 1968, Astrophys. J. (Lett.) 153, L199.Google Scholar
Fritz, G., Meekins, J. F., Henry, R. C., and Friedman, H.: 1969, Astrophys. J. (Lett.) 156, L33.Google Scholar
Frye, G. M. and Wang, C. P.: 1968, Canadian J. Phys. 46, S448.Google Scholar
Frye, G. M., Staib, J. A., Zych, A. D., Hopper, V. D., Rawlinson, W. R., and Thomas, J. A.: 1969, Nature 223, 1320.Google Scholar
Giacconi, R., Gursky, H., and Waters, J. R.: 1965, Nature 207, 572.Google Scholar
Gorenstein, P., Giacconi, R., and Gursky, H.: 1967, Astrophys. J. (Lett.) 150, L85.Google Scholar
Gorenstein, P., Gursky, H., and Garmire, G.: 1968, Astrophys. J. 153, 885.Google Scholar
Gould, R. J.: 1965, Phys. Rev. Lett. 15, 577.Google Scholar
Grader, R. J., Hill, R. W., and Seward, F. D.: 1969, Sky and Telescope 37, 79.Google Scholar
Grader, R. J., Hill, R. W., Seward, F. D., and Hiltner, W. A.: 1970, Astrophys. J. 159, 201.CrossRefGoogle Scholar
Greisen, K. I.: 1968, Brandeis Summer Institute lectures.Google Scholar
Gursky, H., Gorenstein, P., and Giacconi, R.: 1967, Astrophys. J. (Lett.) 150, L75.Google Scholar
Harries, J. R., McCracken, K. G., Francey, R. J., and Fenton, A. G.: 1967, Nature 215, 38.Google Scholar
Hayakawa, S. and Matsuoka, M.: 1964, Prog. Theor. Phys. Suppl. 30, 204.Google Scholar
Haymes, R. C., Ellis, D. V., Fishman, G. J., Glenn, S. W., and Kurfess, J. D.: 1968, Astrophys. J. (Lett.) 151, L131.CrossRefGoogle Scholar
Haymes, R. C., Ellis, D. V., Fishman, G. J., Glenn, S. W., and Kurfess, J. D.: 1969, Astrophys. J. (Lett.) 155, L31.Google Scholar
Hill, R. W., Grader, R. J., and Seward, F. D.: 1968, Astrophys. J. 154, 655.Google Scholar
Hiltner, W. A., Mook, D. E., Ludden, D. J., and Graham, D.: 1967, Astrophys. J. (Lett.) 148, L47.Google Scholar
Hobbs, R. W., Corbett, H. H., and Santini, N. J.: 1968, Astrophys. J. 152, 43.Google Scholar
Holt, S. S. and Ramaty, R.: 1969, Solar Phys. 8, 119.Google Scholar
Holt, S. S., Boldt, E. A., and Serlemitsos, P. J.: 1968, Astrophys. J. (Lett.) 154, L137.Google Scholar
Holt, S. S., Boldt, E. A., and Serlemitsos, P. J.: 1969, Astrophys. J. (Lett.) 158, L155.Google Scholar
Hudson, H. S., Peterson, L. E., and Schwartz, D. A.: 1969, Solar Phys. 6, 205.Google Scholar
Jenkins, E. B. and Morton, D. C.: 1967, Nature 215, 1257.CrossRefGoogle Scholar
Johnson, H. M.: 1966, Astrophys. J. 146, 960.Google Scholar
Johnson, H. M.: 1968, Astrophys. J. 154, 1139.Google Scholar
Johnson, H. M., Spinrad, H., Taylor, B. J., and Peimbert, M.: 1967, Astrophys. J. (Lett.) 149, L45.Google Scholar
Kerr, F. J.: 1969, Ann. Rev. Astron. Astrophys. 7, 39.CrossRefGoogle Scholar
Kraft, R. P. and Demoulin, M.H.: 1967, Astrophys. J. (Lett.) 150, L183.Google Scholar
Kraft, R. P. and Miller, J. S.: 1969, Astrophys. J. (Lett.) 155, L159.CrossRefGoogle Scholar
Lequeux, J.: 1962, Ann. Astrophys. 25, 221.Google Scholar
Lewin, W. H. G., Clark, G. W., and Smith, W. B.: 1968a, Astrophys. J. (Lett.) 152, L55.Google Scholar
Lewin, W. H. G., Clark, G. W., and Smith, W. B.: 1968b, Nature 219, 1235.Google Scholar
Macdonald, G. H., Kenderdine, S., and Neville, A. C.: 1968, Monthly Notices Roy. Astron. Soc. 138, 259.Google Scholar
Manley, O. P. and Olbert, S.: 1969, Astrophys. J. 157, 223.Google Scholar
Mark, H., Price, R., Rodrigues, R., Seward, F. D., and Swift, C. D.: 1969, Astrophys. J. (Lett.) 155, L143.Google Scholar
McClintock, J. E., Lewin, W. H. G., Sullivan, R. J., and Clark, G. W.: 1969, Nature 223, 162.Google Scholar
McGee, R. X., Milton, J. A., and Wolfe, W.: 1966, Australian J. Phys. Suppl. 1.Google Scholar
Moffet, A. T. and Berge, G. L.: 1968, Astrophys. J. 153, 997.Google Scholar
Neugebauer, G., Oke, J. B., Becklin, E., and Garmire, G.: 1969, Astrophys. J. 155, 1.Google Scholar
Ogelman, H.: 1969, Nature 221, 753.Google Scholar
O'Mongain, E. P., Porter, N. A., White, J., Fegan, D. J., Jennings, D. M., and Lawless, B. G.: 1968, Nature 219, 1348.Google Scholar
Overbeck, J. W. and Tananbaum, H. D.: 1968, Astrophys. J. 153, 899.Google Scholar
Peterson, L. E. and Jacobson, A. S.: 1966, Astrophys. J. 145, 962.Google Scholar
Peterson, L. E., Jacobson, A. S., Pelling, R. M., and Schwartz, D. A.: 1968, Canadian J. Phys. 46, S437.Google Scholar
Poveda, A. and Woltjer, L.: 1968, Astron. J. 73, 65.Google Scholar
Prendergast, K. H. and Burbidge, G. R.: 1968, Astrophys. J. (Lett.) 151, L83.Google Scholar
Pronik, V. I., Pronik, I. I., and Chuvaev, K. K.: 1967, Astr. Zu. 44, 965; trans. Soviet Astr. 11, 777 (1968).Google Scholar
Purton, C. R. and Andrew, B. H.: 1969, Nature 222, 863.Google Scholar
Rappaport, S., Bradt, H. V., Naranan, S., and Spada, G.: 1969, Nature 221, 428.Google Scholar
Rees, M. J.: 1968, Astrophys. Lett. 2, 1.Google Scholar
Riegler, G. R.: 1969, dissertation, University of Maryland; Goddard Space Flight Center preprint no. X-611-69-1.Google Scholar
Riegler, G. R. and Ramaty, R.: 1969, Astrophys. Lett. 4, 27.Google Scholar
Rieke, G. H. and Weekes, T. C.: 1969, Astrophys. J. 155, 429.Google Scholar
Rocchia, R., Rothenflug, R., Boclet, D., and Durouchoux, P.: 1969, Astron. Astrophys. 1, 48.Google Scholar
Sandage, A.: 1968, Astrophys. J. (Lett.) 152, L149.Google Scholar
Sandage, A., Osmer, P., Giacconi, R., Gorenstein, P., Gursky, H., Waters, J., Bradt, H., Garmire, G., Sreekantan, B. V., Oda, M., Osawa, K., and Jugaku, J.: 1966, Astrophys. J. 146, 316.Google Scholar
Sartori, L. and Morrison, P.: 1967, Astrophys. J. 150, 385.Google Scholar
Schorn, R. A., Epstein, E. E., Oliver, J. P., Soter, S. L., and Wilson, W. J.: 1968, Astrophys. J. (Lett.) 151, L27.Google Scholar
Shen, C. S.: 1969, Phys. Rev. Lett. 22, 568.CrossRefGoogle Scholar
Shivanandan, K., Houck, J. R., and Harwit, M. O.: 1968, Phys. Rev. Lett. 21, 1460.Google Scholar
Shklovsky, I. S.: 1967, Astrophys. J. (Lett.) 148, L1.Google Scholar
Silk, J. and McCray, R.: 1969, Astrophys. Lett. 3, 59.Google Scholar
Sofia, S., Eichhorn, H., and Gatewood, G.: 1969, Astron. J. 74, 20.Google Scholar
Sturrock, P. A.: 1967, in Plasma Astrophysics, Varenna lectures (ed. by Sturrock, P. A.), Academic Press, New York, p. 338.Google Scholar
Sturrock, P. A.: 1969, in Plasma Instabilities in Astrophysics (ed. by Wentzel, D. G. and Tidman, D. A.), Gordon and Breach, New York.Google Scholar
Tucker, W.: 1967, Astrophys. J. 148, 745.Google Scholar
Verma, S. D.: 1968, Astrophys. J. 152, 537.Google Scholar
Wallerstein, G.: 1967, Astrophys. Lett. 1, 31.Google Scholar
Westphal, J. A., Sandage, A., and Kristian, J.: 1968, Astrophys. J. 154, 139.Google Scholar
Wisniewski, W. and Kleinmann, D. E.: 1968, Astron. J. 73, 866.Google Scholar