Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-26T03:59:22.717Z Has data issue: false hasContentIssue false
  • English
  • Français

Radio Frequency Observations of the Nuclei of Galaxies

Published online by Cambridge University Press:  14 August 2015

R. D. Ekers
R. D. Ekers*
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, The Netherlands

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.

For spiral galaxies the nuclear radio emission is usually dominated by a complex distribution of emission with median diameter of 200 pc and median power of 1019 W Hz−1 sr−1 at 1400 MHz. There is a large range in both power and diameter. The power is independent of morphological type for the normal spirals but is correlated with the absolute optical magnitude and with the infrared emission. For Seyfert galaxies the emission is generally stronger, in some cases by several orders of magnitude (e.g. NGC 1275, 3C 120).

Elliptical galaxies have been found with very compact radio sources, some less than a parsec in diameter. These are as powerful as the strongest spirals (~ 1021 W Hz−1 sr−1). Even stronger compact nuclear sources are now being found in the nuclei of those elliptical galaxies which also have extended radio sources (the radio galaxies). The presence of nuclear sources of this strength is so highly correlated with the presence of extended sources that this suggests a continuing involvement of the nucleus.

Type
Research Article
Information
Symposium - International Astronomical Union , Volume 58: The Formation and Dynamics of Galaxies , 1974 , pp. 257 - 277
Copyright
Copyright © Reidel 1974 

References

Allen, R. J., Ekers, R. D., Burke, B. F., and Miley, G. K.: 1973, Nature 241, 260.Google Scholar
Baldwin, J. E. and Pooley, G. G.: 1973, Monthly Notices Roy. Astron. Soc. 161, 127.Google Scholar
Becklin, E. E., Fomalont, E. B., and Neugebauer, G.: 1973, Astrophys. J. Letters 181, L27.Google Scholar
Branson, N. J. B. A., Elsmore, B., Pooley, G. G., and Ryle, M.: 1972, Monthly Notices Roy. Astron. Soc. 156, 377.Google Scholar
Broderick, J. J., Kellermann, K. I., Shaffer, D. B., and Jauncey, D. L.: 1972, Astrophys. J. 172, 299.Google Scholar
Clark, B. G., Kellermann, K. I., Cohen, M. H., Shaffer, D. B., Jauncey, D. L., Matveyenko, L. I., and Moiseev, I. G.: 1973, Astrophys. J. Letters 182, L57.Google Scholar
Cohen, M. H., Moffet, A. T., Shaffer, D. B., Clark, B. G., Kellermann, K. I., Jauncey, D. L., and Gulkis, S.: 1969, Astrophys. J. Letters 158, L83.Google Scholar
Cohen, M. H., Cannon, W., Purcell, G. H., Shaffer, D. B., Broderick, J. J., Kellermann, K. I., and Jauncey, D. L.: 1971, Astrophys. J. 170, 207.CrossRefGoogle Scholar
Dent, W.: 1971, Science 175, 1105.Google Scholar
De Young, D. S., Roberts, M. S., and Saslaw, W. C.: 1973, Astrophys. J. 185, 809.Google Scholar
Downes, D. and Maxwell, A.: 1966, Astrophys. J. 146, 653.Google Scholar
Ekers, R. D.: 1972, in Evans, D. S. (ed.) ‘External Galaxies and Quasi-Stellar Objects’, IAU Symp. 44, 222.Google Scholar
Ekers, R. D.: 1974, in preparation.Google Scholar
Ekers, R. D. and Ekers, J. A.: 1973, Astron. Astrophys. 24, 247.Google Scholar
Gordon, M. A.: 1974, IAU Symp. 60, in preparation.Google Scholar
Harris, A.: 1972, Monthly Notices Roy. Astron. Soc. 158, 1.Google Scholar
Heeschen, D. S.: 1968, Astrophys. J. Letters 151, L135.CrossRefGoogle Scholar
Heeschen, D. S.: 1970a, Astron. J. 75, 523.Google Scholar
Heeschen, D. S.: 1970b, Astrophys. Letters 6, 49.Google Scholar
Hill, J. M. and Longair, M. S.: 1971, Monthly Notices Roy. Astron. Soc. 154, 125.Google Scholar
Holmberg, E.: 1958, Medd. Lund. Ser II, No. 136.Google Scholar
Kellermann, K. I.: 1971, in O'Connell, D. J. K. (ed.), Nuclei of Galaxies, North-Holland Publ. Co., Amsterdam, p. 217.Google Scholar
Kellermann, K. I.: 1972, in Evans, D. S. (ed.), ‘External Galaxies and Quasi-Stellar Objects’, IAU Symp. 44, 190.Google Scholar
Kellermann, K. I. and Pauliny-Toth, I. I. K.: 1968, Ann. Rev. Astron. Astrophys. 6, 417.Google Scholar
Kellermann, K. I., Clark, B. G., Shaffer, D. B., Cohen, M. H., Jauncey, D. L., Broderick, J. J., and Niell, A. E.: 1973, Astrophys. J. Letters 183, L51.Google Scholar
Klienmann, D. E. and Low, F. J.: 1970, Astrophys. J. Letters 161, L203.Google Scholar
Kronberg, P. P., Pritchet, C. J., and van den Bergh, S.: 1972, Astrophys. J. Letters 173, L47.CrossRefGoogle Scholar
Legg, T. H., Broten, N. W., Fort, D. N., Yen, J. L., Bale, F. V., Barber, P. C., and Quigley, M. J. S.: 1973, Nature 244, 18.Google Scholar
Le Squéren, A. M. and Crovisier, J.: 1974, Astron. Astrophys. 31, 447.Google Scholar
Little, A. G.: 1974, IAU Symp. 60, in preparation.Google Scholar
Macdonald, G. H., Kenderdine, S., and Neville, Ann C.: 1968, Monthly Notices Roy. Astron. Soc. 138, 259.CrossRefGoogle Scholar
Mathewson, D. S., van der Kruit, P. C., and Brouw, W. N.: 1972, Astron. Astrophys. 17, 468.Google Scholar
Miley, G. K. and van der Laan, H.: 1973, Astron. Astrophys. 28, 359.Google Scholar
Northover, K. J. E.: 1973, Monthly Notices Roy. Astron. Soc. 165, 369.CrossRefGoogle Scholar
Oort, J. H.: 1974, IAU Symp. 60, in preparation.Google Scholar
Pooley, G. G.: 1969a, Monthly Notices Roy. Astron. Soc. 144, 101.Google Scholar
Pooley, G. G.: 1969b, Monthly Notices Roy. Astron. Soc. 144, 143.Google Scholar
Riley, J. M.: 1973, Monthly Notices Roy. Astron. Soc. 161, 167.Google Scholar
Riley, J. M. and Branson, N. J. B. A.: Monthly Notices Roy. Astron. Soc. 164, 271.Google Scholar
Robertson, D. S., Gubbay, J. S., and Legg, A. T.: 1973, Proc. Astron. Soc. Australia 2, 184.Google Scholar
Sandage, A. R.: 1972, Quart. J. Roy. Astron. Soc. 13, 282.Google Scholar
Sandage, A. R.: 1972, Astrophys. J. 178, 25.Google Scholar
Sandage, A. R.: 1973, Astrophys. J. 183, 731.Google Scholar
Spencer, J. H.: 1973, , MIT, Cambridge, Mass. Google Scholar
Spencer, J. H. and Burke, B. F.: 1972, Astrophys. J. Letters 176, L101.Google Scholar
van der Kruit, P. C.: 1972, Astron. Astrophys. 15, 110.Google Scholar
van der Kruit, P. C.: 1972, Astrophys. Letters 11, 173.Google Scholar
van der Kruit, P. C.: 1973a, Astron. Astrophys. 29, 231.Google Scholar
van der Kruit, P. C.: 1973b, Astron. Astrophys. 29, 249.Google Scholar
van der Kruit, P. C.: 1973c, Astron. Astrophys. 29, 263.Google Scholar
van der Kruit, P. C., Oort, J. H., and Mathewson, D. S.: 1972, Astron. Astrophys. 21, 169.Google Scholar
Wade, C. M.: 1968, Astron. J. 73, 876.Google Scholar
Wade, C. M., Hjellming, R. M., Kellermann, K. I., and Wardle, J. F. C.: 1971, Astrophys. J. Letters 170, L11.Google Scholar
Whitney, A. R., Shapiro, I. I., Rogers, A. E. E., Robertson, D. S., Knight, C. A., Clark, T. A., Goldstein, R. M., Marandino, G. E., and Vandenberg, N. R.: 1971, Science 173, 225.Google Scholar