1,980 research outputs found
Twenty Years of Searching for (and Finding) Globular Cluster Pulsars
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
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
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
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
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 7500 m), system temperature
(K), high slew speeds (1-2 deg/s), large bandwidths (770 MHz at 20cm
wavelengths), southern hemisphere location (latitude ) 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. 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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