scholarly journals Discovery of H i gas in a young radio galaxy at z = 0.44 using the Australian Square Kilometre Array Pathfinder

2015 ◽  
Vol 453 (2) ◽  
pp. 1249-1267 ◽  
Author(s):  
J. R. Allison ◽  
E. M. Sadler ◽  
V. A. Moss ◽  
M. T. Whiting ◽  
R. W. Hunstead ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
Square Kilometre Array

scholarly journals Erratum: Discovery of H i gas in a young radio galaxy at $\boldsymbol {z = 0.44}$ using the Australian Square Kilometre Array Pathfinder

2015 ◽  
Vol 456 (3) ◽  
pp. 3030-3031 ◽  
Author(s):  
J. R. Allison ◽  
E. M. Sadler ◽  
V. A. Moss ◽  
M. T. Whiting ◽  
R. W. Hunstead ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
Square Kilometre Array

scholarly journals Discovery of a new extragalactic circular radio source with ASKAP: ORC J0102–2450

2021 ◽  
Author(s):  
Bärbel S Koribalski ◽  
Ray P Norris ◽  
Heinz Andernach ◽  
Lawrence Rudnick ◽  
Stanislav Shabala ◽  
...  
Keyword(s):  
Radio Source ◽  
Blast Wave ◽  
Radio Galaxy ◽  
Elliptical Galaxy ◽  
Circular Ring ◽  
The South ◽  
Square Kilometre Array ◽  
South Eastern ◽  
Companion Galaxy

Abstract We present the discovery of another Odd Radio Circle (ORC) with the Australian Square Kilometre Array Pathfinder (ASKAP) at 944 MHz. The observed radio ring, ORC J0102–2450, has a diameter of ∼70 arcsec or 300 kpc, if associated with the central elliptical galaxy DES J010224.33–245039.5 (z ∼ 0.27). Considering the overall radio morphology (circular ring and core) and lack of ring emission at non-radio wavelengths, we investigate if ORC J0102–2450 could be the relic lobe of a giant radio galaxy seen end-on or the result of a giant blast wave. We also explore possible interaction scenarios, for example, with the companion galaxy, DES J010226.15–245104.9, located in or projected onto the south-eastern part of the ring. We encourage the search for further ORCs in radio surveys to study their properties and origin.

Evidence of Energy Nonequipartition between Particles and Fields in Lobes of the Radio Galaxy PKS 1343−601 (Centaurus B)

1998 ◽  
Vol 499 (2) ◽  
pp. 713-718 ◽  
Author(s):  
M. Tashiro ◽  
H. Kaneda ◽  
K. Makishima ◽  
N. Iyomoto ◽  
E. Idesawa ◽  
...  
Keyword(s):  
Radio Galaxy

ASCAObservations of the Broad‐Line Radio Galaxy 3C 445

1998 ◽  
Vol 495 (2) ◽  
pp. 749-756 ◽  
Author(s):  
Rita M. Sambruna ◽  
I. M. George ◽  
R. F. Mushotzky ◽  
K. Nandra ◽  
T. J. Turner
Keyword(s):  
Radio Galaxy ◽  
Broad Line

Evidence of Fermi Acceleration of Lyα in the Radio Galaxy 1243+036

1998 ◽  
Vol 505 (2) ◽  
pp. 634-638 ◽  
Author(s):  
Luc Binette ◽  
Benoit Joguet ◽  
John C. L. Wang
Keyword(s):  
Radio Galaxy ◽  
Fermi Acceleration

scholarly journals A circular polarization survey for radio stars with the Australian SKA Pathfinder

2021 ◽  
Vol 502 (4) ◽  
pp. 5438-5454
Author(s):  
Joshua Pritchard ◽  
Tara Murphy ◽  
Andrew Zic ◽  
Christene Lynch ◽  
George Heald ◽  
...  
Keyword(s):  
Radio Emission ◽  
Brightness Temperature ◽  
Circular Polarization ◽  
Flux Density ◽  
Wide Band ◽  
M Dwarfs ◽  
Square Kilometre Array ◽  
Population Statistics ◽  
Chemically Peculiar ◽  
Radio Stars

ABSTRACT We present results from a circular polarization survey for radio stars in the Rapid ASKAP Continuum Survey (RACS). RACS is a survey of the entire sky south of δ = +41○ being conducted with the Australian Square Kilometre Array Pathfinder telescope (ASKAP) over a 288 MHz wide band centred on 887.5 MHz. The data we analyse include Stokes I and V polarization products to an RMS sensitivity of 250 μJy PSF−1. We searched RACS for sources with fractional circular polarization above 6 per cent, and after excluding imaging artefacts, polarization leakage, and known pulsars we identified radio emission coincident with 33 known stars. These range from M-dwarfs through to magnetic, chemically peculiar A- and B-type stars. Some of these are well-known radio stars such as YZ CMi and CU Vir, but 23 have no previous radio detections. We report the flux density and derived brightness temperature of these detections and discuss the nature of the radio emission. We also discuss the implications of our results for the population statistics of radio stars in the context of future ASKAP and Square Kilometre Array surveys.

scholarly journals Unexpected circular radio objects at high Galactic latitude

2021 ◽  
Vol 38 ◽  
Author(s):  
Ray P. Norris ◽  
Huib T. Intema ◽  
Anna D. Kapińska ◽  
Bärbel S. Koribalski ◽  
Emil Lenc ◽  
...  
Keyword(s):  
Galactic Latitude ◽  
High Galactic Latitude ◽  
Square Kilometre Array ◽  
Pilot Survey ◽  
The Universe

Abstract We have found a class of circular radio objects in the Evolutionary Map of the Universe Pilot Survey, using the Australian Square Kilometre Array Pathfinder telescope. The objects appear in radio images as circular edge-brightened discs, about one arcmin diameter, that are unlike other objects previously reported in the literature. We explore several possible mechanisms that might cause these objects, but none seems to be a compelling explanation.

scholarly journals CNN architecture comparison for radio galaxy classification

2021 ◽  
Vol 503 (2) ◽  
pp. 1828-1846
Author(s):  
Burger Becker ◽  
Mattia Vaccari ◽  
Matthew Prescott ◽  
Trienko Grobler
Keyword(s):  
Comparative Study ◽  
Galaxy Evolution ◽  
Radio Galaxy ◽  
Recognition Performance ◽  
Model Complexity ◽  
Great Promise ◽  
Radio Sources ◽  
Morphological Classification ◽  
Computational Performance

ABSTRACT The morphological classification of radio sources is important to gain a full understanding of galaxy evolution processes and their relation with local environmental properties. Furthermore, the complex nature of the problem, its appeal for citizen scientists, and the large data rates generated by existing and upcoming radio telescopes combine to make the morphological classification of radio sources an ideal test case for the application of machine learning techniques. One approach that has shown great promise recently is convolutional neural networks (CNNs). Literature, however, lacks two major things when it comes to CNNs and radio galaxy morphological classification. First, a proper analysis of whether overfitting occurs when training CNNs to perform radio galaxy morphological classification using a small curated training set is needed. Secondly, a good comparative study regarding the practical applicability of the CNN architectures in literature is required. Both of these shortcomings are addressed in this paper. Multiple performance metrics are used for the latter comparative study, such as inference time, model complexity, computational complexity, and mean per class accuracy. As part of this study, we also investigate the effect that receptive field, stride length, and coverage have on recognition performance. For the sake of completeness, we also investigate the recognition performance gains that we can obtain by employing classification ensembles. A ranking system based upon recognition and computational performance is proposed. MCRGNet, Radio Galaxy Zoo, and ConvXpress (novel classifier) are the architectures that best balance computational requirements with recognition performance.

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