N. P. F. McKay

The Parkes multi-beam pulsar survey - I. Observing and data analysis systems, discovery and timing of 100 pulsars

limiting flux density of the survey is about 0.2 mJy. At shorter or longer periods or higher dispersions, the sensitivity is reduced. Timing observations are carried out for pulsars discovered in the survey for 12‐18 months after confirmation to obtain accurate positions, spin parameters, dispersion measures, pulse shapes and mean flux densities. The survey is proving to be extremely successful, with more than 600 pulsars discovered so far. We expect that, when complete, this one survey will come close to finding as many pulsars as all previous pulsar surveys put together. The newly discovered pulsars tend to be young, distant and of high radio luminosity. They will form a valuable sample for studies of pulsar emission properties, the Galactic distribution and evolution of pulsars, and as probes of interstellar medium properties. This paper reports the timing and pulse shape parameters for the first 100 pulsars timed at Parkes, including three pulsars with periods of less than 100 ms which are members of binary systems. These results are briefly compared with the parameters of the previously known population.

The Parkes Multibeam Pulsar Survey – II. Discovery and timing of 120 pulsars

The Parkes Multibeam Pulsar Survey is a sensitive survey of a strip of the Galactic plane with |b| < 5 ◦ and 260 ◦ < l < 50 ◦ at 1374 MHz. Here we report the discovery of 120 new pulsars and subsequent timing observations, primarily using the 76-m Lovell radio telescope at Jodrell Bank. The main features of the sample of 370 published pulsars discovered during the multibeam survey are described. Furthermore, we highlight two pulsars: PSR J1734−3333, a young pulsar with the second highest surface magnetic field strength among the known radio pulsars, Bs = 5.4 × 10 13 G, and PSR J1830−1135, the second slowest radio pulsar known,

Discovery of a Young Radio Pulsar in a Relativistic Binary Orbit

We report on the discovery of PSR J1141-6545, a radio pulsar in an eccentric, relativistic 5 hr binary orbit. The pulsar shows no evidence of being recycled, having a pulse period P = 394 ms, a characteristic age τc = 1.4 × 106 yr, and an inferred surface magnetic dipole field strength B = 1.3 × 1012 G. From the mass function and measured rate of periastron advance, we determine the total mass in the system to be 2.300 ± 0.012 M☉, assuming that the periastron advance is purely relativistic. Under the same assumption we constrain the pulsars mass to be Mp ≤ 1.348 M☉, and the companions mass to be Mc > 0.968 M☉ (both with 99% confidence). Given the total system mass and the distribution of measured neutron star masses, the companion is probably a massive white dwarf that formed prior to the birth of the pulsar. Optical observations can test this hypothesis.

Discovery of Five Binary Radio Pulsars

We report on five binary pulsars discovered in the Parkes multibeam Galactic plane survey. All of the pulsars are old, with characteristic ages (1-11) × 109 yr, and have relatively small inferred magnetic fields, (5-90) × 108 G. The orbital periods range from 1.3 to 15 days. As a group these objects differ from the usual low-mass binary pulsars (LMBPs): their spin periods of 9-88 ms are relatively long; their companion masses, 0.2-1.1 M☉, are, in at least some cases, suggestive of CO or more massive white dwarfs; and some of the orbital eccentricities, 10-5 e 0.002, are unexpectedly large. We argue that these observed characteristics reflect binary evolution that is significantly different from that of LMBPs. We also note that intermediate-mass binary pulsars apparently have a smaller scale height than LMBPs.

Two Young Radio Pulsars Coincident with EGRET Sources

We report the discovery and follow-up timing observations of two young energetic radio pulsars. PSR J1420-6048 has a period P = 68 ms and period derivative = 83 × 10-15, implying a characteristic age τc = 13 kyr and a surface dipole magnetic field strength B = 2.4 × 1012 G. PSR J1837-0604 has P = 96 ms and = 45 × 10-15, implying τc = 34 kyr and B = 2.1 × 1012 G. The two objects have large spin-down luminosities, and, on the basis of an empirical comparison of their properties with those of other young radio pulsars, they are expected to be observable as pulsed γ-ray sources. In fact, they lie within the error circles of γ-ray sources detected by the EGRET instrument on the Gamma Ray Observatory. We show that the pulsars are plausibly associated with the EGRET sources.

The Parkes Multibeam Pulsar Survey

The Parkes multibeam pulsar survey uses a 13-element receiver operating at a wavelength of 20 cm to survey the inner Galactic plane with remarkable sensitivity. To date we have collected and analyzed data from 45% of the survey region (|b| < 5 deg.; 260 deg. < l < 50 deg.), and have discovered 440 pulsars, in addition to re-detecting 190 previously known ones. Most of the newly discovered pulsars are at great distances, as inferred from a median dispersion measure (DM) of 400 pc/cm^3.

Discovery of two high-magnetic-field radio pulsars

We report the discovery of two isolated radio pulsars having the largest inferred surface dipole magnetic fields yet seen in the population: 4.1×1013 G and 5.5×1013 G. These pulsars show apparently normal radio emission in a regime of magnetic field strength where some models predict no emission should occur. They have spin parameters and magnetic fields similar to those of some magnetar candidates, but exhibit very different radiative properties. This demonstrates that if the putative magnetars are indeed isolated neutron stars, their unusual attributes cannot be only a consequence of their large inferred magnetic fields.

The Parkes Multibeam Pulsar Survey Data Release

The Parkes multibeam pulsar survey began in 1997 and is now about 50% complete. It has discovered more than 400 new pulsars so far, including a number of young, high magnetic field, and relativistic binary pulsars. Early results, descriptions of the survey and follow up timing programs can be found in papers by Lyne et al. (1999 MNRAS in press, astro-ph/9911313), Camilo et al. (astro-ph/9911185), and Manchester et al. (astro-ph/9911319). This paper describes the data release policy and how you can gain access to the raw data and details on the pulsars discovered.