The 69 ms Radio Pulsar Near the Supernova Remnant RCW 103

We report the detection of the radio pulsar counterpart to the 69 ms X-ray pulsar discovered near the supernova remnant RCW 103 (G332.4-0.4). Our detection confirms that the pulsations arise from a rotation-powered neutron star, which we name PSR J1617-5055. The observed barycentric period derivative confirms that the pulsar has a characteristic age of only 8 kyr, the sixth smallest of all known pulsars. The unusual apparent youth of the pulsar and its proximity to a young remnant requires that an association be considered. Although the respective ages and distances are consistent within substantial uncertainties, the large inferred pulsar transverse velocity is difficult to explain given the observed pulsar velocity distribution, the absence of evidence for a pulsar wind nebula, and the symmetry of the remnant. Rather, we argue that the objects are likely superposed on the sky; this is reasonable given the complex area. Without an association, the question of where is the supernova remnant left behind following the birth of PSR J1617-5055 remains open. We also discuss a possible association between PSR J1617-5055 and the gamma-ray source 2CG 333+01. Though an association is energetically plausible, it is unlikely given that EGRET did not detect 2CG 333+01.Comment: 18 pages, 2 encapsulated Postscript figures, uses AAS LaTeX style files. Accepted for publication in The Astrophysical Journal Letter

A Double-Pulsar System - A Rare Laboratory for Relativistic Gravity and Plasma Physics

The clock-like properties of pulsars moving in the gravitational fields of their unseen neutron-star companions have allowed unique tests of general relativity and provided evidence for gravitational radiation. We report here the detection of the 2.8-sec pulsar J0737-3039B as the companion to the 23-ms pulsar J0737-3039A in a highly-relativistic double-neutron-star system, allowing unprecedented tests of fundamental gravitational physics. We observe a short eclipse of J0737-3039A by J0737-3039B and orbital modulation of the flux density and pulse shape of J0737-3039B, probably due to the influence of J0737-3039A's energy flux upon its magnetosphere. These effects will allow us to probe magneto-ionic properties of a pulsar magnetosphere.Comment: 21 pages, 5 figures, Science, in pres

The Double Pulsar System J0737-3039: Modulation of the radio emission from B by radiation from A

We have analyzed single pulses from PSR J0737-3039B, the 2.8-s pulsar in the recently discovered double pulsar system, using data taken with the Green Bank Telescope at 820 and 1400 MHz. We report the detection of features similar to drifting subpulses, detectable over only a fraction of the pulse window, with a fluctuation frequency of 0.196 cycles/period. This is exactly the beat frequency between the periods of the two pulsars. In addition, the drifting features have a separation within a given pulse of 23 ms, equal to the pulse period of A. These features are therefore due to the direct influence of PSR J0737-3039A's 44-Hz electromagnetic radiation on PSR J0737-3039B's magnetosphere. We only detect them over a small range of orbital phases, when the radiation from the recycled pulsar PSR J0737-3039A meets our line of sight to PSR J0737-3039B from the side.Comment: 4 pages, 5 figures, Accepted by ApJ Letters 11 August 200

The High Time Resolution Universe Survey - V: Single-pulse energetics and modulation properties of 315 pulsars

We report on the pulse-to-pulse energy distributions and phase-resolved modulation properties for catalogued pulsars in the southern High Time Resolution Universe intermediate-latitude survey. We selected the 315 pulsars detected in a single-pulse search of this survey, allowing a large sample unbiased regarding any rotational parameters of neutron stars. We found that the energy distribution of many pulsars is well-described by a log-normal distribution, with few deviating from a small range in log-normal scale and location parameters. Some pulsars exhibited multiple energy states corresponding to mode changes, and implying that some observed "nulling" may actually be a mode-change effect. PSRJ1900-2600 was found to emit weakly in its previously-identified "null" state. We found evidence for another state-change effect in two pulsars, which show bimodality in their nulling time scales; that is, they switch between a continuous-emission state and a single-pulse-emitting state. Large modulation occurs in many pulsars across the full integrated profile, with increased sporadic bursts at leading and trailing sub-beam edges. Some of these high-energy outbursts may indicate the presence of "giant pulse" phenomena. We found no correlation with modulation and pulsar period, age, or other parameters. Finally, the deviation of integrated pulse energy from its average value was generally quite small, despite the significant phase-resolved modulation in some pulsars; we interpret this as tenuous evidence of energy regulation between distinct pulsar sub-beams.Comment: Before full MNRAS publication, supplementary material is available temporarily at http://dl.dropbox.com/u/22076931/supplementary_material.pd

Age constraints in the double pulsar system J0737-3039

We investigate the age constraints that can be placed on the double pulsar system using models for the spin-down of the first-born 22.7-ms pulsar A and the 2.77-s pulsar B with characteristic ages of 210 and 50 Myr respectively. Standard models assuming dipolar spin-down of both pulsars suggest that the time since the formation of B is ~50 Myr, i.e. close to B's characteristic age. However, adopting models which account for the impact of A's relativistic wind on B's spin-down we find that the formation of B took place either 80 or 180 Myr ago, depending the interaction mechanism. Formation 80 Myr ago, closer to B's characteristic age, would result in the contribution from J0737-3039 to the inferred coalescence rates for double neutron star binaries increasing by 40%. The 180 Myr age is closer to A's characteristic age and would be consistent with the most recent estimates of the coalescence rate. The new age constraints do not significantly impact recent estimates of the kick velocity, tilt angle between pre and post-supernova orbital planes or pre-supernova mass of B's progenitor.Comment: 5 pages, 2 figures, 1 table, accepted for publication by MNRA

Transformation of a Star into a Planet in a Millisecond Pulsar Binary

Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719-1438, a 5.7 ms pulsar, was detected in a recent survey with the Parkes 64m radio telescope. We show that it is in a binary system with an orbital period of 2.2 h. Its companion's mass is near that of Jupiter, but its minimum density of 23 g cm$^{-3}$ suggests that it may be an ultra-low mass carbon white dwarf. This system may thus have once been an Ultra Compact Low-Mass X-ray Binary, where the companion narrowly avoided complete destruction.Comment: 16 pages, 3 figures. Science Express, in pres

An Improved Calculation of the Non-Gaussian Halo Mass Function

The abundance of collapsed objects in the universe, or halo mass function, is an important theoretical tool in studying the effects of primordially generated non-Gaussianities on the large scale structure. The non-Gaussian mass function has been calculated by several authors in different ways, typically by exploiting the smallness of certain parameters which naturally appear in the calculation, to set up a perturbative expansion. We improve upon the existing results for the mass function by combining path integral methods and saddle point techniques (which have been separately applied in previous approaches). Additionally, we carefully account for the various scale dependent combinations of small parameters which appear. Some of these combinations in fact become of order unity for large mass scales and at high redshifts, and must therefore be treated non-perturbatively. Our approach allows us to do this, and to also account for multi-scale density correlations which appear in the calculation. We thus derive an accurate expression for the mass function which is based on approximations that are valid over a larger range of mass scales and redshifts than those of other authors. By tracking the terms ignored in the analysis, we estimate theoretical errors for our result and also for the results of others. We also discuss the complications introduced by the choice of smoothing filter function, which we take to be a top-hat in real space, and which leads to the dominant errors in our expression. Finally, we present a detailed comparison between the various expressions for the mass functions, exploring the accuracy and range of validity of each.Comment: 28 pages, 13 figures; v2: text reorganized and some figured modified for clarity, results unchanged, references added. Matches version published in JCA

The Parkes multibeam pulsar survey: IV. Discovery of 180 pulsars and parameters for 281 previously known pulsars

The Parkes multibeam pulsar survey has led to the discovery of more than 700 pulsars. In this paper, we provide timing solutions, flux densities and pulse profiles for 180 of these new discoveries. Two pulsars, PSRs J1736-2843 and J1847-0130 have rotational periods P > 6s and are therefore among the slowest rotating radio pulsars known. Conversely, with P = 1.8ms, PSR J1843-1113 has the third shortest period of pulsars currently known. This pulsar and PSR J1905+0400 (P = 3.8ms) are both solitary. We also provide orbital parameters for a new binary system, PSR J1420-5625, which has P = 34ms, an orbital period of 40 days and a minimum companion mass of 0.4 solar masses. The 10 degree-wide strip along the Galactic plane that was surveyed is known to contain 264 radio pulsars that were discovered prior to the multibeam pulsar survey. We have redetected almost all of these pulsars and provide new dispersion measure values and flux densities at 20cm for the redetected pulsars.Comment: 35 pages, accepted for publication in MNRAS, a high quality image of the figure on page 32 is available from http://www.atnf.csiro.au/research/pulsar/images/pmsurvey_fig.p