1,980 research outputs found

    Twenty Years of Searching for (and Finding) Globular Cluster Pulsars

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    Globular clusters produce orders of magnitude more millisecond pulsars per unit mass than the Galactic disk. Since the first cluster pulsar was uncovered twenty years ago, at least 138 have been identified - most of which are binary millisecond pulsars. Because of their origins involving stellar encounters, many of these systems are exotic objects that would never be observed in the Galactic disk. Examples include pulsar-main sequence binaries, extremely rapid rotators (including the current record holder), and millisecond pulsars in highly eccentric orbits. These systems are allowing new probes of the interstellar medium, the equation of state of material at supra-nuclear density, the mass distribution of neutron stars, and the dynamics of globular clusters.Comment: 9 pages, 6 figures. Submitted review for the "40 Years of Pulsars" conference in Montreal, Aug 2007. To be published by the AI

    Installation and Use of Pulsar Search Software

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    Searching for radio pulsars typically requires a bespoke software pipeline to efficiently make new discoveries. In this paper we describe the search process, provide a tool for installing pulsar software, and give an example of a pulsar search.Comment: Tutorial on tempo2 presented at the Beijing pulsar conference during 2011. To appear in "Astronomical Research and Technology" Vol.9, No.3, page 21

    Scalable Solutions for Automated Single Pulse Identification and Classification in Radio Astronomy

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    Data collection for scientific applications is increasing exponentially and is forecasted to soon reach peta- and exabyte scales. Applications which process and analyze scientific data must be scalable and focus on execution performance to keep pace. In the field of radio astronomy, in addition to increasingly large datasets, tasks such as the identification of transient radio signals from extrasolar sources are computationally expensive. We present a scalable approach to radio pulsar detection written in Scala that parallelizes candidate identification to take advantage of in-memory task processing using Apache Spark on a YARN distributed system. Furthermore, we introduce a novel automated multiclass supervised machine learning technique that we combine with feature selection to reduce the time required for candidate classification. Experimental testing on a Beowulf cluster with 15 data nodes shows that the parallel implementation of the identification algorithm offers a speedup of up to 5X that of a similar multithreaded implementation. Further, we show that the combination of automated multiclass classification and feature selection speeds up the execution performance of the RandomForest machine learning algorithm by an average of 54% with less than a 2% average reduction in the algorithm's ability to correctly classify pulsars. The generalizability of these results is demonstrated by using two real-world radio astronomy data sets.Comment: In Proceedings of the 47th International Conference on Parallel Processing (ICPP 2018). ACM, New York, NY, USA, Article 11, 11 page

    The Life and Times of the Parkes-Tidbinbilla Interferometer

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    The Parkes-Tidbinbilla took advantage of a real-time radio-link connecting the Parkes and Tidbinbilla antennas to form the world's longest real-time interferometer. Built on a minuscule budget, it was an extraordinarily successful instrument, generating some 24 journal papers including 3 Nature papers, as well as facilitating the early development of the Australia Telescope Compact Array. Here we describe its origins, construction, successes, and life cycle, and discuss the future use of single-baseline interferometers in the era of SKA and its pathfinders.Comment: Accepted by Journal of Astronomical History & Heritage. arXiv admin note: substantial text overlap with arXiv:1210.098

    MeerTime - the MeerKAT Key Science Program on Pulsar Timing

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    The MeerKAT telescope represents an outstanding opportunity for radio pulsar timing science with its unique combination of a large collecting area and aperture efficiency (effective area ∼\sim7500 m2^2), system temperature (T<20T<20K), high slew speeds (1-2 deg/s), large bandwidths (770 MHz at 20cm wavelengths), southern hemisphere location (latitude ∼−30∘\sim -30^\circ) and ability to form up to four sub-arrays. The MeerTime project is a five-year program on the MeerKAT array by an international consortium that will regularly time over 1000 radio pulsars to perform tests of relativistic gravity, search for the gravitational wave signature induced by supermassive black hole binaries in the timing residuals of millisecond pulsars, explore the interiors of neutron stars through a pulsar glitch monitoring programme, explore the origin and evolution of binary pulsars, monitor the swarms of pulsars that inhabit globular clusters and monitor radio magnetars. In addition to these primary programmes, over 1000 pulsars will have their arrival times monitored and the data made immediately public. The MeerTime pulsar backend comprises two server-class machines each of which possess four Graphics Processing Units. Up to four pulsars can be coherently dedispersed simultaneously up to dispersion measures of over 1000 pc cm−3^{-3}. All data will be provided in psrfits format. The MeerTime backend will be capable of producing coherently dedispersed filterbank data for timing multiple pulsars in the cores of globular clusters that is useful for pulsar searches of tied array beams. All MeerTime data will ultimately be made available for public use, and any published results will include the arrival times and profiles used in the results.Comment: 15 pages, MeerKAT Science: On the Pathway to the SKA, 25-27 May, 2016, Stellenbosch, South Africa, available at: https://pos.sissa.it/277/011/pd
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