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Milliarcsecond Structure of Microarcsecond Sources: Comparison of Scintillating and Nonscintillating Extragalactic Radio Sources

journal contribution
posted on 2023-05-16, 19:30 authored by Ojha, R, Fey, AL, Jauncey, DL, James LovellJames Lovell, Johnston, KJ
We compare the milliarcsecond-scale morphology of scintillating and nonscintillating sources. The scintillating sources are drawn from those flat-spectrum extragalactic radio sources discovered, by the Micro-Arcsecond Scintillation-Induced Variability Survey, to have flux density variability at 5 GHz on timescales from hours to days. Intrinsic source structure information is obtained from previously published and/or publicly available 8.4 GHz Very Long Baseline Array images. A sample of low flux density (Sv=5 GHz. < 0.3 Jy) scintillating sources was compared with a sample of high flux density (Sv=5GHz ∼ 1 Jy) scintillators, as well as a sample of high flux density nonscintillators. All source samples meet the selection criteria of the Micro-Arcsecond Scintillation-Induced Variability Survey, thus ensuring that all three source samples are suitable for comparative study. We find that all scintillating sources (both low and high flux density samples) are significantly more core dominated than nonscintillating sources. Further, the overall source size of the scintillating sources is significantly smaller than that of nonscintillators. There does not appear to be any significant difference between the milliarcsecond-scale morphologies of low and high flux density scintillators. These results demonstrate that it is the core of the radio source that is scintillating.

History

Publication title

The Astrophysical Journal

Volume

614

Issue

2 I

Pagination

607-614

ISSN

0004-637X

Department/School

School of Natural Sciences

Publisher

University of Chicago Press

Place of publication

Chicago, USA

Repository Status

  • Restricted

Socio-economic Objectives

Expanding knowledge in the physical sciences

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