ABSTRACT: Results of an HF survey designed to detect young, distant, and short-period pulsars are presented. The survey detected a total of 100 pulsars, 46 of which were previously unknown. The periods of the newly discovered pulsars range between 47 ms and 2.5 ms. One of the new discoveries, PSR 1259-63, is a member of a long-period binary system. At least three of the pulsars have ages less than 30,000 yr, bringing the total number of such pulsars to 12. The majority of the new discoveries are distant objects with high dispersion measures, which are difficult to detect at low frequencies. This demonstrates that the survey has reduced the severe selection effects of pulse scattering, high Galactic background temperature, and dispersion broadening, which hamper the detection of such pulsars at low radio frequencies. The pulsar distribution in the southern Galaxy is found to extend much further from the Galactic center than that in the north, probably due to two prominent spiral arms in the southern Galaxy.
ABSTRACT: A survey is performed for radar pulsars along the northern galactic
plane at 1400 MHz. Utilizing a fast sampling rate and relatively high
radio frequency, this study minimized the selection effects connected
with high galactic background emission, multipath scattering and
interstellar dispersion, all of which had seriously affected previous
major surveys. The timing data and pulse periods show that the detected
sample is almost an order of magnitude younger than those objects
discovered in previous all-sky surveys.
Monthly Notices of the Royal Astronomical Society 12/1991; 254:177-184. · 4.90 Impact Factor
ABSTRACT: We report the discovery of an 11-ms pulsar, PSR162026, in the closest globular cluster, M4 (NGC6121). It is the fifth millisecond pulsar to be found, and the second in a globular cluster. Unlike the other cluster pulsar, PSR1821 24 in M28 (ref. 1), PSR1620 26 is in a low-mass binary system. This provides strong support for formation mechanisms in which an old neutron star is spun up to millisecond periods by accretion during an X-ray binary phase. The orbit's small eccentricity is likely to have significant implica-tions for both the age of the millisecond pulsar and its surface magnetic field. We conclude that the pulsar's current companion is, in fact, the star which was responsible for the spin-up.
ABSTRACT: An investigation of nulling and subpulse drifting in the two pulsars
PSRs 0809+74 and 0818-13 is presented from data recorded at 408 MHz.
Upper limits are placed, in the case of PSR 0809+74, on the time
constants of the decay and rise of pulse energy at nulls of 0.065 and
0.26 s respectively. Significant drifting is found to occur during nulls
in this pulsar. Its behavior is best described by a sudden change of
drift rate at the start of the null, followed by an exponential
relaxation to the normal drift rate, with emission restarting when a
fixed fraction of the recovery has taken place. A similar phenomenon is
observed for PSR 0818-13. For both pulsars the magnitude of these events
appears to be proportional to the null strength. These observations are
taken as evidence that the entity that is drifting survives in some form
during nulls. An attempt is made to interpret this in terms of current
Monthly Notices of the Royal Astronomical Society 07/1983; 204:519-536. · 4.90 Impact Factor
ABSTRACT: Improved parameters for a sample of 80 newly discovered pulsars have
been obtained at Jodrell Bank. Period derivatives were obtained from
three sets of observations separated by yearly intervals. Improved
dispersion measures and pulse widths are also presented.
Monthly Notices of the Royal Astronomical Society 04/1981; 195:517-522. · 4.90 Impact Factor