RT Journal Article
SR Electronic
T1 Interstellar Scattering of Pulsar Radiation and Its Effect on the Spectrum of NP0532
JF Science
JO Science
FD American Association for the Advancement of Science
SP 1453
OP 1455
DO 10.1126/science.168.3938.1453
VO 168
IS 3938
A1 Cronyn, Willard M.
YR 1970
UL http://science.sciencemag.org/content/168/3938/1453.abstract
AB Angular scattering in the interstellar medium results in multipath dispersion which can amount to more than one pulse period for pulsars of short period and high dispersion measure. The dispersion, if operative, imposes on the pulsation flux a cutoff inversely proportional to the fourth power of the observing wavelength. The low-frequency pulse shape of pulsar NP0532 suggests that this pulsar is subject to such scattering and that the observed low-frequency cutoff in the apparent spectrum is not an intrinsic property of the pulsar. In fact, there is evidence that NP0532 may be identified as the compact, low-frequency source in the Crab Nebula and that the pulsar may radiate in accordance with its high-frequency spectrum down to frequencies as low as 10 megahertz, although the periodic time variations are suppressed by the scattering below 100 megahertz.