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Changing modality behaviour in the radio light curve of blazar PKS B1144 - 379

Citation

Said, NMM and Ellingsen, SP and Liu, J and McCallum, JN and Bignall, HE and Shabala, SS and Reynolds, C, Changing modality behaviour in the radio light curve of blazar PKS B1144 - 379, Monthly Notices of the Royal Astronomical Society, 506, (1) pp. 288-297. ISSN 0035-8711 (2021) [Refereed Article]


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Copyright Statement

This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2021 the authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

DOI: doi:10.1093/mnras/stab1651

Abstract

The highly variable BL Lac object PKS B1144 - 379 was monitored at 6.7 GHz using the Ceduna Radio Telescope with high cadence from 2003 to 2011. Intraday variations due to interstellar scintillation (ISS) were observed throughout the period. To complement our earlier analysis of the ISS and variability of this object, we have investigated the physical origin of changes in the modality of flux density distributions, calculated for ∼14 d observing blocks. Our analysis shows that the flux density distribution is primarily bimodal, but it changes to unimodal during the core brightening and jet expansion phases of the source. The presence of unimodal flux density distributions during these two phases is most likely due to the compactness of the scintillating component and the intrinsic evolution of the source. The existence of unimodality in the flux density distributions associated with specific phases of the source evolution also suggests that changes in the modality are unlikely due to multiple scattering screens. We propose that the physical origin of changes in the modality of the flux density distribution for PKS B1144 - 379 is most likely due to the combination of multiple bright jet features with interstellar scintillation along the line of sight between observer and source. This new approach complements our previous investigations of the temporal evolution of PKS B1144 - 379 that used interstellar scintillation and very long baseline interferometry, and the combination of these techniques provides a crucial starting point for understanding the system.

Item Details

Item Type:Refereed Article
Keywords:methods: statistical – quasars: individual: PKS B1144-379
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Said, NMM (Miss Noor Said)
UTAS Author:Ellingsen, SP (Professor Simon Ellingsen)
UTAS Author:McCallum, JN (Dr Jamie McCallum)
UTAS Author:Shabala, SS (Associate Professor Stas Shabala)
ID Code:145550
Year Published:2021
Deposited By:Physics
Deposited On:2021-07-26
Last Modified:2021-09-22
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