Skip to main content Accessibility help
×
Home

Emission mechanisms in X-ray sources: (Invited discourse)

  • L. Woltjer (a1)

Extract

A large body of spectral information on X-ray sources has now become available, but the interpretation remains ambiguous. If temperature variations and finite optical depth effects are taken into account, almost any spectrum can be fitted to a model of thermal bremsstrahlung. If a suitable energy spectrum is adopted for the relativistic electrons, a wide variety of synchrotron spectra becomes possible. Although one or the other interpretation may seem artificial in some cases, it nevertheless should be pointed out that a strictly isothermal source would be a miracle and that power-law type energy spectra of the relativistic particles can apply over only a limited range of energies. More satisfactory progress can be made when the spectral data are augmented with structural information, when emission lines can be studied and polarization can be measured. Not only do the intensities of emission lines give much more detailed information on the temperature and density in a hot gas than can be derived from the continuum, but at sufficient resolution velocity fields can also be studied. Useful structural information probably can be obtained only if spatial resolution of 1 arc-min or better is achieved. But one has only to look at the situation in radio astronomy to see how essential this information is for the building of quantitative models.

    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Emission mechanisms in X-ray sources: (Invited discourse)
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Emission mechanisms in X-ray sources: (Invited discourse)
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Emission mechanisms in X-ray sources: (Invited discourse)
      Available formats
      ×

Copyright

References

Hide All
Angel, J. R. P.: 1969, to be published.
Burbidge, G. R. and Prendergast, K. H.: 1968, Astrophys. J. (Letters) 151, L83.
Ginzburg, V. L.: 1969, Nature, to be published.
Goldreich, P. and Julian, W. H.: 1969, Astrophys. J., to be published.
Gunn, J. E. and Ostriker, J. P.: 1969, Nature 221, 454.
Heiles, C.: 1964, Astrophys. J. 140, 470.
Neugebauer, G., Oke, J. B., Becklin, E., and Garmire, G.: 1969, Astrophys. J. 155, 1.
Pacini, F.: 1967, Nature 216, 567.
Sartori, L. and Morrison, P.: 1967, Astrophys. J. 150, 385.
Scargle, J. D.: 1969, Astrophys. J. 156, 401.
Shklovsky, I. S.: 1967, Astrophys. J. (Letters) 148, L1.
Trimble, V. L.: 1968, Astron. J. 73, 535.
Woltjer, L.: 1958, Bull. Astron. Inst. Neth. 14, 39.

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed