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Pulsar Studies at High Radio Frequencies

Published online by Cambridge University Press:  12 April 2016

Richard Wielebinski
Richard Wielebinski*
Affiliation:
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

Abstract

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Pulsars were discovered at 81.5 MHz and a lot of the studies of these exciting objects have been made up to the present time at radio frequencies below 1.6 GHz. The reasons for this concentration on the low radio frequency characteristics of pulsars is the fact that the spectra are very steep and that very few radio telescopes exist that are capable of efficient operations at high radio frequencies. The Effelsberg 100-m radio telescope of the Max-Planck-Institut fur Radioastronomie operates regularly up to the frequency of 50 GHz and was used to study pulsars at cm/mm-wavelengths. In the southern skies the Parkes 64-m telescope has been used to study pulsars up to 8.4 GHz. One pulsar has been detected at 87 GHz with the 30-m Pico Veleta telescope of IRAM.

The studies of pulsars over the whole frequency range are of great importance because this is necessary for the elucidation of the mechanism that is responsible for the pulsar emission. The high polarization of pulsar radio emission at lower radio frequencies has supported the hypothesis of a coherent emission mechanism, which is required to generate the high luminosity. It has been known for some time that pulsars, unlike other radio sources, have a lower polarization at high radio frequencies. Recently a change of pulsar spectrum, a flattening or possibly an inversion has been observed at the highest radio frequencies. The inversion of the pulsar spectrum seems to coincide with a complete depolarization of some pulsars.

Millisecond pulsars are less luminous than normal pulsars. This makes them even more difficult to detect at higher radio frequencies. Recent observations have extended the spectra of ten millisecond pulsars up to 4.85 GHz. The results imply that millisecond pulsars have properties very similar to normal (slow) pulsars, which suggests similar emission mechanisms.

Type
Part 3. Studies of Radio Emission
Information
International Astronomical Union Colloquium , Volume 177: Pulsar Astronomy - 2000 and Beyond , 2000 , pp. 205 - 210
Copyright
Copyright © Astronomical Society of the Pacific 2000

References

Backer, D.C., Kulkarni, S.R., Heiles, C. et al. 1982, Nature, 300, 615 CrossRefGoogle Scholar
Bartel, N., Sieber, W., & Wielebinski, R. 1977, A&A, 55, 319 Google Scholar
Bartel, N., Sieber, W., & Wielebinski, R. 1978, A&A, 68, 361 Google Scholar
Hewish, A., Bell, S.J., Pilkington, J.D.H. et al. 1968, Nature, 217, 709 Google Scholar
von Hoensbroech, A., & Xilouris, K.M. 1997, A&AS, 126, 121 Google Scholar
von Hoensbroech, A., Kijak, J., & Krawczyk, A. 1998, A&A, 334, 571 Google Scholar
von Hoensbroech, A. 1999, PhD thesis, Bonn University Google Scholar
Kijak, J., Kramer, M., Wielebinski, R., & Jessner, A. 1997, A&A, 318, L63 Google Scholar
Kijak, J., Kramer, M., Wielebinski, R., & Jessner, A. 1998, A&AS, 127, 153 Google Scholar
Kramer, M., Xilouris, K.M., Jessner, A. et al. 1996, A&A, 306, 867 Google Scholar
Kramer, M., Jessner, A., Doroshenko, O., & Wielebinski, R. 1997, ApJ, 488, 364 Google Scholar
Kramer, M., Xilouris, K.M., Lorimer, D.R. et al. 1998, ApJ, 501, 270 Google Scholar
Kramer, M., Lange, C., Lorimer, D.R. et al. 1999, ApJ (in press)Google Scholar
Kuzmin, A.D., & Losovsky, B.Ya. 1996, A&A, 308, 91 Google Scholar
Lorimer, D.R., Yates, J.A., Lyne, A.G., & Gould, D.M. 1995, MNRAS, 273, 411 Google Scholar
Lyne, A.G., & Smith, F.G. 1968, Nature, 218, 124 Google Scholar
Malofeev, V., & Malov, I. 1980, Soviet Ast., 24 (10), 54 Google Scholar
Malofeev, V., Gil, J.A., Jessner, A. et al. 1994, A&A, 285, 201 Google Scholar
Manchester, R.N. 1971, ApJS, 23, 283 Google Scholar
Manchester, R.N., Taylor, J.H., & Huguenin, G.R. 1973, ApJ, 179, L7 Google Scholar
Moffet, D.A., & Hankins, T.H. 1999, ApJ, 522, 1046 CrossRefGoogle Scholar
Morris, D.A., Graham, D.A., Sieber, W. et al. 1981, A&AS, 46, 421 Google Scholar
Morris, D.A., Kramer, M., Thum, C. et al. 1997, A&A, 322, L17 Google Scholar
Radhakrishnan, V., & Cooke, D.J. 1969, Astrophys. Lett., 3, 225 Google Scholar
Robinson, B.J., Cooper, B.F.C., Gardner, F.F. et al. 1968, Nature, 218, 1143 CrossRefGoogle Scholar
Seiradakis, J.H., Gil, J., Graham, D.A. et al. 1995, A&AS, 111, 205 Google Scholar
Sieber, W. 1973, A&A, 28, 237 Google Scholar
Sieber, W., Reinecke, R., & Wielebinski, R. 1975, A&A, 38, 169 Google Scholar
Smith, F.G. 1977 in Pulsars (Cambridge: Cambridge University Press), 118 Google Scholar
Taylor, J.H., Manchester, R.N., & Lyne, A.G. 1993, ApJS, 88, 529 CrossRefGoogle Scholar
Wielebinski, R., Sieber, W., Graham, D.A. et al. 1972, Nature, 240, 131 Google Scholar
Wielebinski, R., Jessner, A., Kramer, M., & Gil, J. 1993, A&A, 272, L13 Google Scholar
Xilouris, K.M., Kramer, M., Jessner, A. et al. 1996, A&A, 309, 481 Google Scholar
Xilouris, K.M., Kramer, M., Jessner, A. et al. 1998, ApJ, 501, 286 CrossRefGoogle Scholar