Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Spectral variability of radio sources at low frequencies

    91603.pdf (1.893Mb)
    Access Status
    Open access
    Authors
    Ross, Kat
    Callingham, J.R.
    Hurley-Walker, Natasha
    Seymour, Nick
    Hancock, Paul
    Franzen, Thomas
    Morgan, John
    White, S.V.
    Bell, M.E.
    Patil, P.
    Date
    2021
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Ross, K. and Callingham, J.R. and Hurley-Walker, N. and Seymour, N. and Hancock, P. and Franzen, T.M.O. and Morgan, J. et al. 2021. Spectral variability of radio sources at low frequencies. Monthly Notices of the Royal Astronomical Society. 501 (4): pp. 6139-6155.
    Source Title
    Monthly Notices of the Royal Astronomical Society
    DOI
    10.1093/mnras/staa3795
    ISSN
    0035-8711
    Faculty
    Faculty of Science and Engineering
    School
    School of Elec Eng, Comp and Math Sci (EECMS)
    Department of Physics and Astronomy
    Funding and Sponsorship
    http://purl.org/au-research/grants/arc/FT190100231
    Remarks

    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

    URI
    http://hdl.handle.net/20.500.11937/91779
    Collection
    • Curtin Research Publications
    Abstract

    Spectral variability of radio sources encodes information about the conditions of intervening media, source structure, and emission processes. With new low-frequency radio interferometers observing over wide fractional bandwidths, studies of spectral variability for a large population of extragalactic radio sources are now possible. Using two epochs of observations from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey that were taken one year apart, we search for spectral variability across 100-230 MHz for 21 558 sources. We present methodologies for detecting variability in the spectrum between epochs and for classifying the type of variability: either as a change in spectral shape or as a uniform change in flux density across the bandwidth. We identify 323 sources with significant spectral variability over a year-long time-scale. Of the 323 variable sources, we classify 51 of these as showing a significant change in spectral shape. Variability is more prevalent in peaked-spectrum sources, analogous to gigahertz-peaked spectrum and compact steep-spectrum sources, compared to typical radio galaxies. We discuss the viability of several potential explanations of the observed spectral variability, such as interstellar scintillation and jet evolution. Our results suggest that the radio sky in the megahertz regime is more dynamic than previously suggested.

    Related items

    Showing items related by title, author, creator and subject.

    • Spectral properties and the effect on redshift cut-off of compact active galactic nuclei from the AT20G survey
      Chhetri, R.; Ekers, Ronald; Mahony, E.; Jones, P.; Massardi, M.; Ricci, R.; Sadler, E. (2012)
      Spectral index has been traditionally used to separate extragalactic radio sources into compact and extended populations, with the spectral transition placed variably between -0.4 and -0.6. We use high angular resolution ...
    • Wide-band spectral variability of peaked spectrum sources
      Ross, Kat ; Hurley-Walker, Natasha ; Seymour, Nick ; Callingham, J.R.; Galvin, Tim ; Johnston-Hollitt, Melanie (2022)
      Characterizing spectral variability of radio sources is a technique that offers the ability to determine the astrophysics of the intervening media, source structure, emission, and absorption processes. We present broadband ...
    • The spectral variability of the GHz-peaked spectrum radio source PKS 1718-649 and a comparison of absorption models
      Tingay, Steven; Macquart, Jean-Pierre; Collier, J.; Rees, G.; Callingham, J.; Stevens, J.; Carretti, E.; Wayth, Randall; Wong, G.; Trott, C.; McKinley, B.; Bernardi, G.; Bowman, J.; Briggs, F.; Cappallo, R.; Corey, B.; Deshpande, A.; Emrich, D.; Gaensler, B.; Goeke, R.; Greenhill, L.; Hazelton, B.; Johnston-Hollitt, M.; Kaplan, D.; Kasper, J.; Kratzenberg, E.; Lonsdale, C.; Lynch, Mervyn; McWhirter, S.; Mitchell, D.; Morales, M.; Morgan, E.; Oberoi, D.; Ord, Stephen; Prabu, T.; Rogers, A.; Roshi, A.; Shankar, N.; Srivani, K.; Subrahmanyan, R.; Waterson, M.; Webster, R.; Whitney, A.; Williams, A.; Williams, C. (2015)
      Using the new wideband capabilities of the ATCA, we obtain spectra for PKS 1718-649, a well-known gigahertzpeaked spectrum radio source. The observations, between approximately 1 and 10 GHz over 3 epochs spanning approximately ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.