scholarly journals Pulsar Science with the SKA

2017 ◽  
Vol 13 (S337) ◽  
pp. 158-164 ◽  
Author(s):  
Evan F. Keane
Keyword(s):  
Milky Way ◽  
Phase 1 ◽  
Square Kilometre Array

AbstractThe Square Kilometre Array (SKA) will be sensitive enough to discover all of the pulsars in the Milky Way that are beamed towards Earth. Already in the initial deployment, SKA Phase 1, it will make significant advances in pulsar science. In these proceedings I briefly overview what the SKA is, and describe its pulsar search and timing capabilities.

scholarly journals A search for radio afterglows from gamma-ray bursts with the Australian Square Kilometre Array Pathfinder

2021 ◽  
Vol 503 (2) ◽  
pp. 1847-1863
Author(s):  
James K Leung ◽  
Tara Murphy ◽  
Giancarlo Ghirlanda ◽  
David L Kaplan ◽  
Emil Lenc ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Phase 1 ◽  
Spectral Energy Distribution ◽  
Early Time ◽  
Gamma Ray Bursts ◽  
Spectral Energy ◽  
Density Parameter ◽  
Square Kilometre Array ◽  
Optical Images ◽  
Celestial Sphere

ABSTRACT We present a search for radio afterglows from long gamma-ray bursts using the Australian Square Kilometre Array Pathfinder (ASKAP). Our search used the Rapid ASKAP Continuum Survey, covering the entire celestial sphere south of declination +41○, and three epochs of the Variables and Slow Transients Pilot Survey (Phase 1), covering ∼5000 square degrees per epoch. The observations we used from these surveys spanned a nine-month period from 2019 April 21 to 2020 January 11. We cross-matched radio sources found in these surveys with 779 well-localized (to ≤15 arcsec) long gamma-ray bursts occurring after 2004 and determined whether the associations were more likely afterglow- or host-related through the analysis of optical images. In our search, we detected one radio afterglow candidate associated with GRB 171205A, a local low-luminosity gamma-ray burst with a supernova counterpart SN 2017iuk, in an ASKAP observation 511 d post-burst. We confirmed this detection with further observations of the radio afterglow using the Australia Telescope Compact Array at 859 and 884 d post-burst. Combining this data with archival data from early-time radio observations, we showed the evolution of the radio spectral energy distribution alone could reveal clear signatures of a wind-like circumburst medium for the burst. Finally, we derived semi-analytical estimates for the microphysical shock parameters of the burst: electron power-law index p = 2.84, normalized wind-density parameter A* = 3, fractional energy in electrons ϵe = 0.3, and fractional energy in magnetic fields ϵB = 0.0002.

scholarly journals Can Square Kilometre Array phase 1 go much beyond the LHC in supersymmetry search?

2019 ◽  
Vol 99 (2) ◽  
Author(s):  
Arpan Kar ◽  
Sourav Mitra ◽  
Biswarup Mukhopadhyaya ◽  
Tirthankar Roy Choudhury
Keyword(s):  
Phase 1 ◽  
Square Kilometre Array

scholarly journals Measuring magnetism in the Milky Way with the Square Kilometre Array

2015 ◽  
Author(s):  
Marijke Haverkorn ◽  
Takuya Akahori ◽  
Ettore Carretti ◽  
Katia Ferrière ◽  
Peter Frick ◽  
...  
Keyword(s):  
Milky Way ◽  
Square Kilometre Array

Novel RFI Mitigation Methods in the Square Kilometre Array 1 Mid Correlator Beamformer

2019 ◽  
Vol 08 (01) ◽  
pp. 1940011 ◽  
Author(s):  
Thushara Gunaratne ◽  
Brent Carlson ◽  
Gianni Comoretto
Keyword(s):  
Radio Frequency ◽  
Radio Telescope ◽  
Phase 1 ◽  
Empirical Studies ◽  
Radio Frequency Interference ◽  
Clock Frequency ◽  
Square Kilometre Array ◽  
Cross Correlations ◽  
Mitigation Methods ◽  
The Impact

The Square Kilometre Array (SKA) Phase 1 Mid Correlator Beamformer (Mid.CBF) adopts two novel methods to mitigate radio frequency interference (RFI) at the various stages of its signal chains. First, the pioneering Sample Clock Frequency Offset (SCFO) sampling suppresses interference which leaks into individual ‘Frequency-Slice’ (FS) (sub-bands) in the cross-correlations. Second, the ‘Shift-Resample-Shift-Back’ method minimizes the addition of noise due to strong clustered RFI. Empirical studies conducted with simulation of the systems confirm that the proposed methods significantly reduce the impact of RFI on the output of the radio telescope.

scholarly journals Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018: Technical specifications and performance forecasts

2020 ◽  
Vol 37 ◽  
Author(s):  
◽  
David J. Bacon ◽  
Richard A. Battye ◽  
Philip Bull ◽  
Stefano Camera ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Redshift ◽  
Phase 1 ◽  
Percent Level ◽  
Weak Lensing ◽  
Square Kilometre Array ◽  
Intensity Mapping ◽  
Systematic Effects ◽  
Technical Specifications ◽  
Run Up

Abstract We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5 000 deg2; a wide and deep continuum galaxy and HI intensity mapping (IM) survey over 20 000 deg2 from $z = 0.35$ to 3; and a deep, high-redshift HI IM survey over 100 deg2 from $z = 3$ to 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to $z \sim 3$ with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to $z = 6$ . These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical and near-infrared (NIR) surveys like Euclid, LSST, and WFIRST leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.

scholarly journals Cosmic magnetism with the Square Kilometre Array and its pathfinders

2008 ◽  
Vol 4 (S259) ◽  
pp. 645-652 ◽  
Author(s):  
Bryan M. Gaensler
Keyword(s):  
Magnetic Fields ◽  
Faraday Rotation ◽  
Milky Way ◽  
High Redshift ◽  
Wide Field ◽  
Square Kilometre Array ◽  
Origin And Evolution ◽  
Science Projects ◽  
Nearby Galaxies ◽  
High Redshift Universe

AbstractOne of the five key science projects for the Square Kilometre Array (SKA) is “The Origin and Evolution of Cosmic Magnetism”, in which radio polarimetry will be used to reveal what cosmic magnets look like and what role they have played in the evolving Universe. Many of the SKA prototypes now being built are also targeting magnetic fields and polarimetry as key science areas. Here I review the prospects for innovative new polarimetry and Faraday rotation experiments with forthcoming facilities such as ASKAP, LOFAR, the ATA, the EVLA, and ultimately the SKA. Sensitive wide-field polarisation surveys with these telescopes will provide a dramatic new view of magnetic fields in the Milky Way, in nearby galaxies and clusters, and in the high-redshift Universe.

scholarly journals A Census of Southern Pulsars at 185 MHz

2017 ◽  
Vol 34 ◽  
Author(s):  
Mengyao Xue ◽  
N. D. R. Bhat ◽  
S. E. Tremblay ◽  
S. M. Ord ◽  
C. Sobey ◽  
...  
Keyword(s):  
Phase 1 ◽  
Low Frequency ◽  
Frequency Component ◽  
Frequency Resolution ◽  
Large Field ◽  
Initial Time ◽  
Wide Field ◽  
Processing Load ◽  
Square Kilometre Array ◽  
Murchison Widefield Array

AbstractThe Murchison Widefield Array, and its recently developed Voltage Capture System, facilitates extending the low-frequency range of pulsar observations at high-time and -frequency resolution in the Southern Hemisphere, providing further information about pulsars and the ISM. We present the results of an initial time-resolved census of known pulsars using the Murchison Widefield Array. To significantly reduce the processing load, we incoherently sum the detected powers from the 128 Murchison Widefield Array tiles, which yields ~10% of the attainable sensitivity of the coherent sum. This preserves the large field-of-view (~450 deg2 at 185 MHz), allowing multiple pulsars to be observed simultaneously. We developed a WIde-field Pulsar Pipeline that processes the data from each observation and automatically folds every known pulsar located within the beam. We have detected 50 pulsars to date, 6 of which are millisecond pulsars. This is consistent with our expectation, given the telescope sensitivity and the sky coverage of the processed data (~17 000 deg2). For 10 pulsars, we present the lowest frequency detections published. For a subset of the pulsars, we present multi-frequency pulse profiles by combining our data with published profiles from other telescopes. Since the Murchison Widefield Array is a low-frequency precursor to the Square Kilometre Array, we use our census results to forecast that a survey using the low-frequency component of the Square Kilometre Array Phase 1 can potentially detect around 9 400 pulsars.

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