Pulsar Search at the Molonglo Radio Observatory

The efficiency of a light-emitting diode (LED) is limited because a large amount of generated light is confined inside due to total internal reflection. It is well known that light extraction from LEDs can be enhanced by using photonic crystal. However, the underlying physical mechanisms for increased emission are still largely unknown. In this work, we used the finite difference time domain method to analyze the photonic crystal (PC) LED with disordered air holes. The light extraction efficiency of disordered PC was nearly equivalent to that of ordered PC with the same pattern periodicity. This result supported the idea that the increased light extraction of PC LED was mainly due to the scattering, which is irrelevant to photonic band structure.

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“…East-west array of Mills Cross. Direct pen records, with special means for detecting pulsars with high dispersion (Large and Vaughan 1971).…”

Section: T H E Character Of the Signalsmentioning

confidence: 99%

Analysis of Disordered Photonic Crystal Implemented in Light-Emitting Diode for High Light Extraction Efficiency

Long

Hwang

Ryu

2008

jjap

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“…PSR J0837−4135 (B0835−41). This pulsar was discovered at 408 MHz by Large et al (1968) and Wang et al (2001) used the Nanshan radio telescope at Xinjiang Astronomical Observatory to update the period and period derivative. The 8.6 GHz profile for this pulsar ( Fig.…”

Section: Psr J0659+1414 (B0656+14)mentioning

confidence: 99%

TMRT Observations of 26 Pulsars at 8.6 GHz

Zhao

Yan

et al. 2017

ApJ

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Integrated pulse profiles at 8.6 GHz obtained with the Shanghai Tian Ma Radio Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities and pulse width parameters of these pulsars are estimated. For eleven pulsars these are the first high-frequency observations and for a further four, our observations have a better signal-to-noise ratio than previous observations. For one (PSRs J0742−2822) the 8.6 GHz profiles differs from previously observed profiles. A comparison of 19 profiles with those at other frequencies shows that in nine cases the separation between the outmost leading and trailing components decreases with frequency, roughly in agreement with radius-to-frequency mapping, whereas in the other ten the separation is nearly constant. Different

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“…During the earliest surveys, manual selection involved the inspection of analogue pen chart records for periodic signals (Large et al 1968;Manchester et al 1978). This process was subsequently replaced by digital data inspection, with the adoption of early computer systems.…”

Section: Manual Selectionmentioning

confidence: 99%

Fifty years of pulsar candidate selection: from simple filters to a new principled real-time classification approach

Lyon

Stappers

Cooper

et al. 2016

Mon. Not. R. Astron. Soc.

190

174

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Improving survey specifications are causing an exponential rise in pulsar candidate numbers and data volumes. We study the candidate filters used to mitigate these problems during the past fifty years. We find that some existing methods such as applying constraints on the total number of candidates collected per observation, may have detrimental effects on the success of pulsar searches. Those methods immune to such effects are found to be ill-equipped to deal with the problems associated with increasing data volumes and candidate numbers, motivating the development of new approaches. We therefore present a new method designed for on-line operation. It selects promising candidates using a purpose-built tree-based machine learning classifier, the Gaussian Hellinger Very Fast Decision Tree (GH-VFDT), and a new set of features for describing candidates. The features have been chosen so as to i) maximise the separation between candidates arising from noise and those of probable astrophysical origin, and ii) be as survey-independent as possible. Using these features our new approach can process millions of candidates in seconds (∼1 million every 15 seconds), with high levels of pulsar recall (90%+). This technique is therefore applicable to the large volumes of data expected to be produced by the Square Kilometre Array (SKA). Use of this approach has assisted in the discovery of 20 new pulsars in data obtained during the LOFAR Tied-Array All-Sky Survey (LOTAAS).

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Pulsar Search at the Molonglo Radio Observatory

Cited by 54 publications

References 12 publications

Analysis of Disordered Photonic Crystal Implemented in Light-Emitting Diode for High Light Extraction Efficiency

Analysis of Disordered Photonic Crystal Implemented in Light-Emitting Diode for High Light Extraction Efficiency

TMRT Observations of 26 Pulsars at 8.6 GHz

Fifty years of pulsar candidate selection: from simple filters to a new principled real-time classification approach

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