Colin J. Clark

THE EINSTEIN@HOME GAMMA-RAY PULSAR SURVEY. I. SEARCH METHODS, SENSITIVITY, and DISCOVERY of NEW YOUNG GAMMA-RAY PULSARS

We report on the results of a recent blind search survey for gamma-ray pulsars in Fermi Large Area Telescope (LAT) data being carried out on the distributed volunteer computing system, Ein-stein@Home. The survey has searched for pulsations in 118 unidentified pulsar-like sources, requiring about 10, 000 years of CPU core time. In total, this survey has resulted in the discovery of 17 new gamma-ray pulsars, of which 13 are newly reported in this work, and an accompanying paper. These pulsars are all young, isolated pulsars with characteristic ages between 12 kyr and 2 Myr, and spin-down powers between 10 34 and 4 × 10 36 erg s −1. Two of these are the slowest spinning gamma-ray pulsars yet known. One pulsar experienced a very large glitch ∆f /f ≈ 3.5 × 10 −6 during the Fermi mission. In this, the first of two associated papers, we describe the search scheme used in this survey, and estimate the sensitivity of our search to pulsations in unidentified Fermi-LAT sources. One such estimate results in an upper limit of 57% for the fraction of pulsed emission from the gamma-ray source associated with the Cas A supernova remnant, constraining the pulsed gamma-ray photon flux that can be produced by the neutron star at its center. We also present the results of precise timing analyses for each of the newly detected pulsars.

The Braking Index of a Radio-quiet Gamma-ray Pulsar

We report the discovery and timing measurements of PSR J1208-6238, a young and highly magnetized gamma-ray pulsar, with a spin period of 440 ms. The pulsar was discovered in gamma-ray photon data from the Fermi Large Area Telescope (LAT) during a blind-search survey of unidentified LAT sources, running on the distributed volunteer computing system Einstein@Home. No radio pulsations were detected in dedicated follow-up searches with the Parkes radio telescope, with a flux density upper limit at 1369 MHz of 30 μJy. By timing this pulsars gamma-ray pulsations, we measure its braking index over five years of LAT observations to be n=2.598±0.001±0.1, where the first uncertainty is statistical and the second estimates the bias due to timing noise. Assuming its braking index has been similar since birth, the pulsar has an estimated age of around 2,700 yr, making it the youngest pulsar to be found in a blind search of gamma-ray data and the youngest known radio-quiet gamma-ray pulsar. Despite its young age the pulsar is not associated with any known supernova remnant or pulsar wind nebula. The pulsars inferred dipolar surface magnetic field strength is 3.8×1013 G, almost 90% of the quantum-critical level. We investigate some potential physical causes of the braking index deviating from the simple dipole model but find that LAT data covering a longer time interval will be necessary to distinguish between these.

LOFAR Discovery of the Fastest-spinning Millisecond Pulsar in the Galactic Field

We report the discovery of PSR J0952

The Einstein@Home Gamma-ray Pulsar Survey. II. Source Selection, Spectral Analysis, and Multiwavelength Follow-up

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High-energy Variability of PSR J1311-3430

0607, a 707-Hz binary millisecond pulsar which is now the fastest-spinning neutron star known in the Galactic field (i.e., outside of a globular cluster). PSR J0952

On the highest energy emission from millisecond pulsars

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GAMMA-RAY TIMING OF REDBACK PSR J2339–0533: HINTS FOR GRAVITATIONAL QUADRUPOLE MOMENT CHANGES

0607 was found using LOFAR at a central observing frequency of 135 MHz, well below the 300 MHz to 3 GHz frequencies typically used in pulsar searches. The discovery is part of an ongoing LOFAR survey targeting unassociated Fermi Large Area Telescope

Optimized Blind Gamma-ray Pulsar Searches at Fixed Computing Budget

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Kepler K2 observations of the transitional millisecond pulsar PSR J1023+0038

-ray sources. PSR J0952

Blind Search Methods for Binary Gamma-ray Pulsars

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